evaluation of spinal kinematics
TRANSCRIPT
Evaluation of Spinal Kinematics Using the ~astrak""
During the Trunk Velocity Test
Marcio A. Marqal
A thesis submitted to the School of Physical and Hcalth
Education in partial fulfillment of the requirements for the
Degree of Doctor of Philosophy
Queen's University
Kingston, Ontario, Canada
August, 1999
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Abstract
Objective tests for low back pain have been used for clinical screening, as a
quantitative indicator of treatment progress, and even as an indicator of readiness to
return to work. (Triano & Schultz, 1987; Binkely, 1999). In 1988, Marras and Wongsanl
reported that the tnmk's angular wlocitp awing unloaded dynamic activity could bd i i 4
to discriminate between healthy and low back pain (LBP) subjects. In further studics.
using the Lumbar Motion Monitor (LMM), these findings were confirmed and. in
addition the trunk's angular acceleration was reported to be another important measure
(Marras et al., 1993; Marras et al., 1994).
The Polhemus ~ a s t r a k ~ ~ electro-magnetic motion tracking system is a device for
the measurement of the three-dimensional position and orientation of sensors in spacc. Its
use in understanding the kinematics of the spine has advantage over the LMM, since i t
allows the investigator to assess the thoracic, thoracolumbar, lumbar and sacral regions at
the same time. The aim of this thesis was to study the reliability and repeatability of thc
trunk velocity test using the ~ a s t r a k ' ~ and the applicability of this device in the
assessment of the spinal kinematics of healthy and low back pain subjects d u r i n ~ lhc
trunk velocity test.
The trunk velocity test using the ~ a s t r a k ~ ~ proved to be reliably, repeatable and
was also capable of measuring spinal motion statically in all planes and dynamically
motion in flexion. Kinematic values recorded using ~as t rak '~ ' showed excellent
agreement with the values published in the literature. A free test protocol was compared
to a restricted test protocol during the trunk velocity test. The former was suggested as a
standard since i t can be used with devices other than the LMM and allowcd thc subjects
perform the trunk velocity test using their total spinal range of motion.
The trunk velocity test was performed by 30 healthy and 44 LBP subjects, who
were divided into moderate low back pain (MLBP) and severe low back pain (SLBP)
subgroups. The results showed that the kinematic variables for the thoracic,
thoracolumbar, and lumbar segments, and sacral angle obtained through the trunk
velocity test were significantly different between the severe low back pain group and the
healthy and also between the severe low back pain and the moderate low back p u n
subgroups. The thoracic peak velocity and peak acceleration variables were significant
different between the two subgroups of LBP. The thoracic peak velocity was also the
only variable sensitive to identify differences in subjects who developed LBP in a
longitudinal study.
The present series of studies assessing spinal kinematics showed that the
~ a s t r a k ~ ~ devise and the trunk velocity test are promising in clinical and industnal
settings. The thoracic segment was responsible for important results suggesting that more
studies should be canied out to investigate potential informations that could be extracted
from this segment to better understand the complexity of the low back pain problem.
References
1. Binkely JM: Measurement of functional status,progress,and outcome in orthopaedic clinical practice. Orthopaedic Practice 1 1 : 14-2 1. 1999.
2. Marras WS, Wongsam PE: Flexibility and velocity of the normal and impaired lumbar spine. Archives of Physical Medicitre Reliabilitatiorl 6 7 2 13-2 17. 1986.
3. Marras WS, Parnianpour M, Ferguson SA, Kim JY, Crowell RR, Simon SR: Quantification and ilassifiiatiol~ of low back disorders based on trunk motion. European Jozrrnal of Physical Medicine Reabilitorio?l 3:2 1 8-235. 1 993.
I. Marras WS, Parnianpour M, Kim JY, Ferguson SA, Crowell RR, Simon SR: Thc effect of task asymmetry, age and gender on dynamic trunk motion characteristics during repetitive trunk motion characteristics during repetitive trunk flexion and extension in a large normal population. IEEE Trunsuctiorls or1 Rehabilitariori Erigineering 2 : 1 37- 1 46, 1 994.
5 . Triano JJ, Schultz AB: Correlation of objective measure of trunk motion and muscle function with low-back disability ratings. Spiw 1 2:56 1-565, 1987.
Acknowledgments
I wish to acknowledge the support and encouragement of my advisor. Dr. Joan
Stevenson, whose positive outlook made this project possible. I appreciate her friendship
and kindness during the years I have lived in Kingston.
I recognize the assistance of my co-supervisor, Dr. Pat Costigan, for his critical
input and hendly guidance, especially during the writing process of this thesis.
Endless thanks to my wife, Claudia, for her endless encouragement and time in
helping me accomplish this dissertation. Her constant love and support inspired me to
keep going. I also extend my appreciation to my children, Bruno and Julia. Despite their
young age. they were capable of understanding the demands on Daddy and showed
patience in dealing with the countless hours without Daddy's attention.
Appreciation is also extended to Dr. Bill Pearce, who developed the analysis
software used in this research project.
I would like to express my gratitude to Wayne Albert, whose constant friendship.
interest and available time helped me in the completion of this work.
I also acknowledge the volunteers, specifically the employees from Dupont
(Kingston) Inc. and members of the Kingston Community, who donated their time to
make this study possible.
A special thanks to my parents, who went above the call of duty to provide rnc
with the best in education and always showing their support for me in many ways.
My thanks to CAPES (Coordena~lo de Aperfei~oamento de Pessoal de Nivcl
Superior) for their financial support, without which this opportunity ro study abroad
would not have been possible.
Co- Authorship
It is the intent that, aside fiom the introduction, each chapter will be published as
3 paper in a refereed journal. The following is the list of the proposed papers to bc
published. Paper 4 makes use of data collected during the Dupont longitudinal back pain
study, which was ssupportcd by Satural Science d Enginrering Research Counc~i of
Canada.
1. Marqal MA, Costigan PA, Stevenson J. Reliability and repeatability of the trunk
velocity test using ~ a s t r a k ~ ~ . To be submitted to Spine.
2. Marqal MA, Costigan PA, Stevenson J . Trunk velocity test: comparative study
between ~astrak'~ and Lumbar Motion Monitor. To be submitted to Clinical
Biomechanics.
3. Marpl MA, Stevenson J, Costigan PA. The use of the trunk velocity test in healthy
and low back pain subjects. To be submitted to Journal of Physical Therapy.
3. Mar@ MA, Stevenson J, Costigan PA. The use of the trunk velocity test in an
industrial population. To be submitted to Spine
Table of Contents
Abstract .................................... .. ........................................................ 1
Acknowledgments ............................................................................... itr
Co- Authorship ................................. .. ..... vi
Table of Contents ................................................................................... vii
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . List of Tables ..., I
List of Figures ............................... .. ................................................... x i i
Chapter 1 : introduction ....................................................................... 1
............................................. Epidemiology and costs of low back pain problems 1
Contributing factors to LBP ........................................................................ 4
Individztnl risk factors ........................................................................... 4
....................................................................... Occtcpationui risk factors 7
........................................................ Clinical aspects of the low back pain 1 1
Rationale .......................................................................................... 13
Thesis outline and purpose ....................................................................... 1 5
References .......................................................................................... 16
Chapter 2: ~ a s t r a k ~ ~ Reliability and Repeatability of Kinematics Variables from
Spinal Segments During the Truo k Velocity Test ....................................... 24
Introduction ......................................................................................... 24
Methods ......................... .. ................................................................. 2 7
Equipment set-up ............................................................................... 27
Subjects ........................................................................................... 2 8
Test protocols ........................ .. ........................................................ - 3 0
Datu Analysis: .................................................................................... 31
Results .............................................................................................. 35
Descriptive data .............................................................................. 3 5
Repeatability .................... .. ............................................................ 3 6
vii
Refiu hilit! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -3 O
Discussion .............................. .... ..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -42
Descriptive data .,.............................................................................. .-I2
Repearabili~ ........................................ a 7
Refiahiliiy .................................................................................... A 8
Conclusion ......................................................................................... 52
References ...................................... .. 3
Chapter 3: Trunk velocity test: comparative study between ~astrak'" and
......................................................................... Lumbar Motion Monitor 58
Introduction .......................................................................................... 58
Mct hods ............................................................................................ -60
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Equipment set-up u~td attuchme)~r bo
.................................................................................. Testing protocol 62
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Strrlll, I : Compartsor~ of protocols usirlg LMM 64
........................................ Stl& 2: Conpvison between ~ostrak"' m d L MM 66
Data Analysis ...................................................................................... 66
............................................................................................. Results -68
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Study I : Comparison ofprotocols using LMM 68
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Study 2: ~orn~ar i son between FastrakrM and LMM 69
Discussion .......................................................................................... 73
.............................................. Stuctv I : Comparjson of protocols using L MM 73
...................................... Study 2: Comparisorr between FastrakTM a d LMM 51
Conclusion .................................... .. ................................................. 84
References ......................................................................................... -85
Chapter 4: The use of the trunk velocity test in healthy and low back
.................................................. pain subjects .................................. 87
........................................................................................ Introduction 87
............................................................................................ Methods -91
Strhjec~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Questionnaire and Pain Scale ...................................... 9 2
Trunk Velocity Test ............................................................................ 92
Duta Anolysis ................................................................................. 93
Results .............................................................................................. 94
Discussion ........................................................................................ 100
Conclusion ........................................................................................ 103
References ................................................................ 14U
Chapter 5:Queen's-Dupont study: the use of the trunk velocity test in a
longitudinal study .......................... .. ................................................ 108
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 !(I
Trwk Velocity Test ........................................................................... l l t
L)isability Qrtestiorlnaire ................... .. .......................................... i l l
Dnto Awl-vsis ................................................................................ -113
Results ............................. .. ........................................................... 115
Discussion ........................................................................................ 116
Conclusion ........................................................................................ 124
References ........................................................................................ 126
Chapter 6: General Discussion and Conclusion .......................................... 129
Biomechanics of the spine during ihe trunk velocity resr ............................... 131
....................................... Comparison between healthy and SLBP subjects 132
.............................. Comparison between healthy. MLBP and SLBP subjects 135
.................................... Kinematic variables as predictors of LBP disability 1 38
....................................................................................... Sitmntuly 1 3 9
...................................................................................... Conclusions -139
.................................................................................. Future Research 140
References ....................................... .. !
Appendices
................................................................... Appendix 1 : Consent Form I ...A I
Appendix 2: Consent Form 11 ...................... .. ......................................... A2
.................................................... Appendix 3: Multiple Regression Analysis I A3
,Maximum ROM flex1011 .................................................................... ..A 3-1
Peak velociv ............................................................................... .A 3.2
................................................. Peak accelera tio rz . . . . . 43-3
................................................................. Appendix 4: Consent Fonn 111 ..A 4
Appendix 5: Pain Scale ...................................................................... A5
.............................................. Appendix 6: Working Condition Questionnaire A6
.................................................. Appendix 7: Multiple Regression Analysis I1 A7
Appendix 8: Consent Form IV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . AS
List of Tables
Chapter 1
Introduction
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Table 1.1 Individual and occupational risk factors j
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Table 1.2 Activities associated with industrial back injuries . l o
Chapter 2
~ a s t r a k ~ ~ Reliability and Repeatability of Kinematics Variables
from Spinal Segments During the Trunk Velocity Test
Table 2.1 Descriptive data for spinal kinematic variables (N = 10) ....................... .3 7
............. Table 2.2 Repeatability of the trunk velocity test using MANOVA 0\1 = 10) .3S
Table 2.3 Tukey's HSD test peak displacement. Trial 1 X trial 2 (N = 10) .. . . . . . . . . . . . . . . . 39
Table 2.4 lntraclass correlation coefficients (ICC) for spinal kinematic variables ...... .4 1
Table 2.5 Comparison of static ROM values for spinal motion between current study and
the scientiiic literature ............................................................... .43
. . . . . . . . . . . . . . . . . . . . . . . . . . Table 2.6 Lumbar segment dynamic ROM flexion and velocity 4 4
Table 2.7 Thoracolumbar segment dynamic maximum ROM flexion, velocity and
acceleration .......................................................................... -46
Table 2.8 Intraclass correlation coefficients (ICC) and Pearson correlation coefficients (r)
.................................................... for static ROM lumbar segment .50
Table 2.9 Reliability coefficients for lumbar segment dynamic maximum ROM, velocity
and acceleration .................................................................... .5 1
Chapter 3
Trunk velocity test: comparative study between ~ a s t r a k ' ~ "
and Lumbar Motion Monitor
Table 3.1 Comparison of protocol using LMM - descriptive data and Pearson product-
moment correlation (N = IS) . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70
Table 3.2 Comparison between ~ a s t r a k ~ ~ and LMM - descriptive data and Pearson
product-moment correlation (N = 10). . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .72
Table 3.3 Descriptive data for spinal kinematic variables from ~ a s t r a k . ' ~ . . . . . ... . . . . . . . . .74
Table 3.4 Pearson correlation (r) for spinal kinematic variables . . . .. . . . . . . . . . . . . . . . . . . . . . . . .77
Chapter 4
The use of the trunk velocity test in healthy and
low back pain subjects
Table 4.1 Demographic information for the healthy and LBP subjects . . . . .. . . . . . . . . . . . . ..95
Table 4.2 Descriptive data for spinal kinematic variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... 97
Table 4.3 Bonfenoni test . . .. . .. . . .. .. .. .. .. . .. . .. . . . .. . . . . .. . . . . . . - . . . . . . . . . . . . . . . , . . ... 98
Table 4.4 Pearson correlation coefficients (r) between disability score and spinal
kinematic variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . ..99
Chapter 5
Queen's-Dupont study: the use of the trunk velocity test
in a longitudinal study
Table 5.1
Tah!e 5.2
Tab
Tab
.................... Demographic information for the no LBP and LBP groups 1 17
Descriptive data for ?he spinal vrtri&les md the ?-value for thc indcpsntcni
sample T-test ........................................................................ . lX
Comparison among studies of the thoracic, lumbar. and sacral kinematic
Variables ............................................................................. 1 22
Comparison between Dupont and Chapter 4 study in terms of thoracic
kinematic variables and level of disability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -123
... Xlll
List of Figures
Chapter 2
~ a s t r a k ~ ~ Reliability and Repeatability of Kinematics Variables
from Spinal Segments During the Trunk Velocity Test
Figure 2.1 hstrakTM set up ....................................................................... 20
. . . . . . . . . Figure 2.2 Trunk velocity test in: A) standing position and B) flexed position - 3 2
Figure 2.3 Schematic to demonstrate the calculated angles A) thoracic segment, B )
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . thoracoiumbar segment, and C) lumbar segment .34
Figure 2.1 Comparison of peak ROM flexion values and standard deviation bars on day
one for trial one through eight A) thoracic segment. B) thoracolumbar
. . . . . . . . . . . . . . . . . . . . . . . . . segment. C) lumbar segment, and D) sacral angle .. . .W
Chapter 3
Trunk velocity test: comparative study between ~ a s t r a k ~ "
and Lumbar Motion Monitor
Figure 3.1 Subject set up for the LMM: (A) only the harness system, and (B) thc
.............................................. ...................... complete set up .. 6 1
Figure 3.2 lvIonitor feedback screen: (A) before test start, and (B) during the
test .................................. .. .............................................. -63
Figure 3.3 Trunk velocity test LMM: (A) RTP and (B) FTP .............................. -65
Figure 3.4 Trunk velocity test free test protocol: (A) using ~ a s t r a k ~ ~ and (B)
using LMM. These tests were performed separately because the LMM
................. metal harness interfered with the FASTRAK measurements .67
Figure 3.5 Correlation between trunk velocity test protocols: The regression line
XIV
and the 95% confidence interval bands are shown for (A) maximum
. . . . . . . . . . . . . . . . . . . ROM flexion. (B) peak velocity, and (C) peak acceleration 71
Figure 3.6 Thoracic and lumbar segments kinematic correlations: (A) masimum ROM
. . . . . . . . . . . . . . . . . . . . . . . . . flexion, (B) peak velocity, (C) and peak acceleration . ? j
Figure 3.7 Representative examples of dynamic ROM flexion thoracic, thoraco lurnbar.
................. lumbar segments and sacral angle for two subjects (A and B) 76
Figure 3.8 Cornparis011 of the kinematic variables between studies that used RTP to
perfonn trunk velocity test. !A! Dynamic ROM flesinn, (I?) Peak v e l ~ c l t y ,
........................................................ and (C) Peak acceleration .7<1
Figure 3.9 Comparison of the kinematic variables between studies that used FTP to
perfonn trunk velocity test. (A) Dynamic ROM flexion, (B) Peak velocity.
and (C) Peak acceleration ......................................................... .SO
Figure 3.10 Trunk velocity test kinematic variables comparison between studies thar used
free test protocol. (A) Dynamic ROM flexion. (B) Peak velocity, and (C)
peak acceleration ................................................................... .S3
Chapter 5
Queen9s-Dupont study: the use of the trunk velocity test
in a longitudinal study
Figure 5.1 ~ a s t r a k ~ " set up sensors at thoracic vertebrae 1 (T1 ), lumbar vertebrae 2
(L2). and sacral region ............................................................. 1 12
Figure 5.2 Calibration test area: (A) calibration frame, (B) observed space, and (C)
corrected space .................................................................... I 14
Figure 5.3 Sequence of low back pain occurrence in the two year follow up ............ .I18
Figure 5.4 Level of disability among LBP subjects ......................................... 1 19
Figure 5.5 Thoracic peak velocity and the first occurrence of LBP ....................... .125
Chapter 6
General Discussion and Conclusion
Figure 6.1 Patterns of motions for: (A) Thoracic (TH), (B) Thoracolurnbar (TL), 7 1 (C) Lumbar segments (LU) and sacral angle (SA) ...........................
Figure 6.2 Thoracic patterns of motion from healthy subjects ........................... .I36
Figure 6.3 Cornpanson of thoracic pattern of motion among healthy. MLBP and SLBP
subjects ............................................................................... 1 3 7
xvi
Chapter 1
Introduction
Low back pain is generally defined as lunbosacral pain as well as buttocks and
leg pain (Rainville et al., 1996). Pain in the back is common symptom of backache.
which most of people have at some point in their lives, a number of spinal diseases and
low back disability (McGregor et al., 1998). LOW back pain can be classified by duration:
acute - at least 6 weeks duration with immediate onset; subacute .- at least 6 weeks
duration but with slow onset; chronic - more that 6 weeks of symptoms; and recurring -
symptoms recumng afler an interval of no symptoms (Nachemson B Bigos, 1984; Erdil
et al., 1997). According to the World Health Organization, impairment is defined as "any
loss or abnormality of psychological, physiological. or anatomical structure or function"
and disability is "any restriction or lack of ability to perform an activity in the nlanrler or
within the range considered normal for a human being that results from an impairment"
(Moon et al., 1997). Back pain brings together these two distinct clinical concepts: low
back impairment and low back disability.
Epidemiology and costs of low back pain problems
Low back pain is prevalent among the working population. According to Johns et
al. (1994), approximately 10 million employees in the United States suffer back pain that
impairs their performance. In addition, back injuries are the most Frequently occurring
workplace disorder, accounting for 22% of workplace injuries and 32% of work&
compensation costs. European countries also have problems related to back pain wlth
10uh to 15% of all absenteeism in their industries caused by back disorders (Versloot el
al., 1992). In the United Kingdom, 25% of all working men are affected by back pain. A
study in Denmark that involved 928 workers found that 22.5% had work absence.
needed some job adjustment, and 63% changed their jobs because of back pain
(Andersson et al., 1991). The incidence o f back pain is also high and likely related to
working conditions in the Nordic countries (Christensen et al., 1995). In the Netherlands,
21% of medical absences and 32% of permanent disability are diagnosed as
"musculoskeletal disorders" and back pain constitutes the largest propoflion (Hildcbrandi.
1995). A study of LBP incidence in more than 3000 workers in Japan showed a lifetimc
prevalence of 60.5% with the highest incidence affecting workers in the age rangc of 4O
to 49 years (Matusi et a\., 1997).
In Canada, the situation is not different. Abenhaim and Suissa (1987) studied the
incidence rates of occupational LBP in the province of Quebec over one year (1981 ).
They reported that 1.37% of the work force of Quebec was absent from work for at least
one episode of LBP, resulting in a total cost of 173 million dollars Canadian for the
government. The Canadian Centre for Occupational Health & Safety (CCOHS) recently
reported that each year 8000 Canadian workers are permanently disabled by back injuries
while many others are unable to return to their former jobs. Such back injuries account
for about one third of all lost work and 40% of all compensation costs (CCOHS, 1999).
The high incidence of back injuries in industry is responsible for the high costs to
employers, insurance companies and the workers themselves. Numerous studies have
estimated the costs associated with back pain over the years. In the 79's. the cs t~rna~cd
costs varied From $1 1.9 billion to $14 billion (Khalil et al.. 1993; Snook. 1988; Taylor,
1986). In early 803, this figure rose up to $31 billion (Taylor, 1986) and low back
injuries were responsible for one third of all compensation costs and for one out of c ~ c y
five cornpensable injuries (Morris, 1984). Webster and Snook (1989) studied all workcrs'
compensation back injury claims in forty-five states in the United States. They concluded
that. in 1989. the cost per case of back pain was more than twice the amount for thc
average workers' compensation claims and that the number of back pain cases
represented 16% of the total number compensation cases. In early 90's, the direct medical
costs associated with low back problems alone exceeded $24 billion (Lahad et al.. 199 1 ;
Khalil et al., 1993).
Although it seems that there has been a constant increase of incidcncc and costs
related to low back injuries, a recent study (Murphy &. Volinn. 1999) has rcponed
otherwise. The annual US. estimate of LBP claim rate decreased by 34% between 1987
and 1995 and the annual estimate of LBP payments decreased by 58% in the same period.
The authors suggested that the decreasing rates are due to aggresswe LBP preventive
programs, early returns to work, ergonomic interventions, and rehabilitation programs
that are more oriented to the workforce. Although the results were optimist, LBP
continues to be a sizable problem in the U.S. workplace.
Contributing Factors to LBP
The factors contributing to back pain can be divided into individlial and
occupational factors. These factors have been studied to determine their association with
the incidence and prevalence of back pain. Andersson and Pope (1991 1 stated thc
importance of understanding which individual characteristics increase [he risk of back
injury. However, information regarding the individual characteristics and their
relationship to increased injury risk is far from complete and the research literature is
frequently contradictory. According to Pope et al. (1 991). it is difficult to determine the
relationship between risk factors and back pain because: ( I ) back injury is not easily
defined. (2) sickness absence data are influenced not only by pain. but also by physical
and psychological work factors. social Factors. and the insurance system. (3) exposurc is
difficult to determine, and (4) there is a poor relationship between physical tests and
disability. Table 1.1 summarizes the risk factors for back pain found in the literature.
Individual risk factors
Many individual risk factors have been reported as contributors to the
development of back injuries. The attack of pain normally begins in young adulthood and
reaches its maximal frequency in the ages between 35 to 55 years (Ferguson & Marras,
1997). There is no predilection for sex, although the incidence of some back problems is
higher in men than in women (Ferguson & Marras, 1997). This may be because the
number of men in physically demanding jobs is greater than women (Lonstein & Wiesel,
1988).
Table 1 .1 - Individual and occupational risk factors
Individual Risk Factors Occupational Risk Factors I I
---! Physical Factors Postural Factors
Body weight Sitting Body height I I
Back muscle strength Rend-over work posture - Leg length differences Lumbar mobility
Static work posture
Physical fitness and training Psychological Factors
Anxiety Depression Fear Hypochondriasis Hysteria Personality traits Stress Tension
Socio-Economic Factors Income Drug abuse Family problems Alcohol abuse Educational level
Other Factors Age Gender Pregnancy Medical history Smoking Nutrition Racial differences
I Psychological Factors I
I
Monotonous work Anxiety Work satisfaction Stress Tension
Kinesiology Li fling Twisting Bending Pulling Pushing Carrying Lowering
1
0th er Factors Heavy physical work I
Repetitive work Vibration I
Fallinglslipping !
i Job safisfaction Years of employment
(Data from Biering-Sorensen, 1984; Kelsey & Golden, 1988; Andersson, 1991; Garg & Moore, 1992; and Papageorgiou et al. 1997)
A variety of physical factors related to back injury have been the subjccc of
current research. Anthropometric factors such as body weight, body height, les length
differences correlate poorly with back pain (Biering-Sorensen, 1984; Masset et a]., 1908).
However, some studies show that tall people and people with leg length discrepancies
appear to have a greater probability of developing back problems (Anderson ct al..
1991). Some aspects of physical fitness are generally believed to be related to back
injury. Research indicates that the occurrence of muscle-skeletal injuncs in wcakrr
workers is up to three times greater than in stronger workers (Kroemer, 1992). Cady ct al.
(1979) found that physically fit firefighters were less apt to have LBP, but when an injury
occurred i t was usually more serious perhaps because of larger loads or a willingness to
exert more force. In addition, it has been reported that most of the back injuries arc the
result of muscle weakness, tightness and fatigued muscles due to lack of physical fitness
(Locker, 1985). Isometric back muscle strength has been shown not to be a predictor for
LBP (Bigos et al., 1991; Masset et al., 1998), but contradictory results have been reported
also (Biering-Sorensen, 1984). Although back pain may cause restriction in the back
mobility, the majority of the studies showed no evidence that spinal ROM could be used
as a test to predict low back pain (Troup et al.. 1987; Battie et al., 1990; Bigos et al..
1992; Garg & Moore, 1992;).
Psychological and socio-economic factors have been considered risk factors Sor
back injuries, but these relationships are not clear yet. Psychological factors may give rise
to or exacerbate complaints and disability about chronic back problems (Cameron &
Shepel, 1988). Some researchers relate hysteria, hypochondriasis, somatization and
depression to back pain, but it is unclear whether the psychological abnormalities arc the
cause or the result of continued back pain symptoms (Fryrnoyer & Anderson. 1991 ).
Alcohol and drug abuse may contribute to workplace accidents (Kelsey & Golden. 1985)
and psychological disturbance which then lead to low back injury (Cameron & Shepel.
1988). Andersson (1981) found that patients with low back pain tend to have family
problems, lower level of education, less income and more difficult establishing emotional
contacts than the general population.
Occupational risk factors
In the workplace back pain has been the subject of several studies because of the
large number of workers who claim that their back pain was caused on the job (Battic &
Bigos, 1991: Bigos et al. 1992, Chnstensen et al. 1995). Factors such as, lifting, heavy
physical work, static posture, stress and others have been considered to have an important
role in the development of low back pain. The employees' postures such as, standing.
sitting and bending-over during the work activities can greatly affect back pain
(Andersson, 198 1). Kelsey and Golden (1 988) found that staying in standing position for
a long period of time increased the probability of back pain. Nachemson (1985) reported
that the intradiscal pressure is higher in a sitting posture than when standing or lying
down, and also, that this force would increase the magnitude of stress on the low back
region. It is also believed that back injury is more frequent in people with a
predominantly bent over work posture when the load on the back is increased (Bullock &
Bullock-Saxton, 1994). Other aspects that have been studied are the static work poslures
involving sustained postures requiring s static contraction. During this contraction the
blood supply is impaired and waste products may accumulate in the muscles thus
originating pain. I f the static work postures are repeated Requently and for a long period
of time, they may result in chronic back pain (Grandjean 6r Hunting, 1997).
The kinesiologic occupational risk factors are those related to motions performed
by the workers. such as, lifting, twisting, bending, pulling, pushing, carrying and
lowering, which might be the mechanisms responsible for the beginning of low back
injuries. Most of the time these motions are related to manual material handling ( M M H )
tasks (Andersson, 1991). The MMH injuries are overexertion in nature where workers
usually exceed their strength or endurance capability (Genaidy et al., 1994). In 198 1, the
Natianal Institute for Occupational Safety and Health (NIOSH) identified some
potentially hazardous aspects related to the act of manually lifting a load. These arc:
weight, location/site, f?equency/duration/pace. stability, coupling, workplace geometry
and environment. Table 1.2 shows the percentage of injuries that are associated wirh
lifting, bending, twisting and pulling (Cassidy & Wedge, 1988). Hochanadel and Conrad
(1993) found that 2,095 of low back pain cases had the following causes: insidious onset,
33%; bending, 31%; lifting. 20%; twisting, 7 O h ; others, 9%. Many authors have agreed
that the combination of twisting, bending and lifting increase the risk for work-related
back injury (Garg & Moore, 1992; Gundewall et al., 1993; CCOHS, 1999).
Heavy physical activities and vibration exposure have been shown to be
significant risk factors in back injury. The back pain experienced by individuals involved
in heavy physical work is more common than those involved in sedentary activity
(Andersson, 198 1 ; Cassidy & Wedge, 1988). According to Snook ( 1988) and Chaffin and
Andersson (1991), there are two to eight times more back disability in the heavy
occupation (manual material handlers) than in the light occupation (clerical workers).
Research with nurses and aides has shown that the risk of getting a back injury I S hiphcr
with a heavy workload compared to those reporting lighter workload (Fcldstein et a]..
1993; Gundewall et al., 1993). Vibrations are found in heavy equipment operator. hand
tools and seats of vehicles. Their effects are transmitted and absorbed by the spine
(Bullock & Bullock-Saxton, 1994) and have a direct impact on the paraspinal muscles
and in the intervertebral discs (Pope et al., 1991). These factors suggest that workers
exposed to whole body vibration have an increasing risk of low back pain (Andcrsson.
199 1 ; Masset & Malchaire, 1994).
Psychological factors, monotonous work, anxiety, stress. tension, and work
dissatisfaction have been found to increase the risk of back injuries (Cameron & Shcpcl.
1988). Workers with monotonous jobs requiring little concentration have a longer
sickness absence following back pain than others (Pope et al., 199 1 ). Several researchers
have found diminished work satisfaction to be related to an increase in back pain (Battie
& Bigos, 1991; Papageorgiou et al., 1997). Anxiety, stress and emotional tension cause
muscles to become tense which in turn creates constant static contractions, that lead to an
increased susceptibility to pain (Snook. 1988).
Over the years many attempts have been made to identify the main contributors of
the development of low back pain. Indeed, many factors acting as a group or in isolation
can play a role in this aggravating problem. These facts makes it difficult to fully
understand LBP etiology.
Clinical Aspects of the Low Back Pain
The ability to determine objectively the extent and severity of physical
impairment due to LBP dysfunction has not been an easy task. According to Spratt et al.
(1990). a precise diagnosis is unknown in 80% to 90% of disabling LBP disorders.
Therefore, appropriate treatment becomes more difficult to administer.
Several assessment methods are currently being used to detect and classify people
with LBP. The initial assessmeut normally consists of a focused medical history, physical
examination and pathoanatomic evaluation of the spine using X-rays, magnetic resonance
image (MRI) or computer tomography (CT). Although the pathoanatomic evaluation
sives a good picture of the problem, one may not be able to identify either the cause or
source of the patients' structural problem. In addition, only 15% of the LBP patients
might have a correct pathoanatomic diagnosis (Nachemson, 1985).
Other LBP assessments use a functional method that involves the quantitative
measurement of trunk strength. Several studies of back muscle strength have documented
an association between trunk muscle strength and LBP (Klein et al., 1991; Newton et al.,
1993; Hupli et al., 1996). Although healthy individuals and mild LBP disease can bc
reliably measured using standard strength tests (Hupli et al., 1996), there exists a concern
over the safety associated with strength testing in subjects with more severe LBP (Marras
et al., 1993).
ROM tests have been used as a routine procedure in the clinical evaluation of'
LBP and as a tool for evaluating the rehabilitation treatment. According to Wolf et al.
(19791, patients with LBP develop compensatory postural abnormalities and movements
over time that are believed to alter thc normal neurornuscular functioning, which affects
their ROM. Nouven et al. (1987) supported these findings by reporting that LBP patients
have different ROM values than normal individuals.
Many studies have shown that the trunk ROM is decreased in patients with LBP
when compared to normal subjects (Waddell et al.. 1992) regardless of the etiology or
disease (Dvorak et a]., 1991). Dynamic measures of LBP have been suggested be more
sensitive than the traditional static measures, such as ROM and isometric strength.
Marras and Wongsan (1 986) report that trunk angular velocity was a good quantirative
measure to distinguish between patients with LBP disorders and normal subjects. Recent
studies have shown thal dynamic measures, such as angular velocity and acceleration of
the lumbar spine, are stronger indicators of LBP than ROM measures (Masset et al.,
1993; Mmas et al., 1994).
Goniometers, photometric technjques, electrogoniometers, isokinetic machines.
inclinometers, X-rays, Lumbar Motion Monitor (LMM), Fastrak and lsotrak have been
widely used to quantify trunk ROM and researches have used ROM to distinguish
between normal and LBP subjects (Mayer et al., 1984; Hindle et a]., 1990; Dvorak et a].,
199 1 ; McIntyre et al., 1991). The LMM (Marras et al., 1993) and the isokinetic machines
(Masset et al., 1993) are the only techniques that has been used to quantify trunk angular
velocity as an indicator of LBP.
Rationale
The ability to design an outcome measure to identify subjects with LBP is a
challenge, since LBP is influenced by a range of variables such as individual perception
and interpretation of their symptoms, physical, psychological and psychosocial aspects,
and working environment influences (Moon et al., 1997; MacGregor et al. 1998 1.
Subjective and objective low back pain tests have been used for clinical
screening, and as a quantitative indicator of treatment progress or even as an indicator of
readiness to return to work. (Triano & Schultz, 1987; Binkely, 1999). Several low back
pain disability questionnaires have been used to assess the patients' perception of their
functional status (Fairbanks et al. 1980; Bergner et al., 198 1 ; Roland & Moms. 1983;
Evans & Kagan, 1986), but as a subjective tests, they are susceptible to perceptual and
belief mismatches (Moon et al., 1997).
Different physical tests have been developed to assess people with LBP. The
quantitative nature of these tests is important, because it allows objective discrimination
between healthy and LBP individuals. In 1988, Marras and Wongsarn reported that. for
the first time, the angular velocity of the trunk during unloaded dynamic activity
discriminated between healthy and LBP subjects. Lumbar ROM and lumbar angular
velocity were used to quantify this difference. These findings were confirmed in further
studies that also included trunk angular acceleration (Marras et al., 1993; Marras et al.,
1994). In all these studies triaxial electrogoniometers (Lumbar Motion Monitor - LMM)
were used to collect the data. According to Marras et al. (1995), the measurement of
unloaded trunk motion may also be accomplished using similar measurement devices to
the LMM (e. g., infrared, video. magnetic tracking devices) and would probably product
similar results. However, these measurement tools would not allow the i~sc oC the same
protocol administered by Mamas et al. (1994), which used specific software designed for
the LMM. As such, in order to use other devices to perform the trunk velocity test, i t is
important to introduce a protocol. which allows comparison among outcomes from
different devices by following the same testing procedures.
Electromagnetic tracking systems have been increasingly used as a kinematic
measuring tool. Kinematics studies of the lumbar spine have evaluated the spinc ROM in
healthy and LBP people (Pearcy et al, 1989; Hindle et al.. 1990; Albert et a].. 1997) and
during lifting (Dolan and Adams, 1993, Nelson et al., 1995), but no study has used an
electromagnetic device, while performing the trunk velocity test.
The Polhernus ~ a s t r a k ' ~ electro-magnetic motion tracking system is a device for
the measurement of the three-dimensional position and orientation of sensors in space. I t
can be used with up to four sensors, which allows the investigator to assess not only the
lumbar segment, but also the thoracic and thoracolumbar segments and sacral anglc.
Using the ~ a s a a k ~ ~ in evaluating the trunk velocity test may provide another device for
the clinical assessment of LBP subjects. Most researchers (Hindle et a\.. 1990; Dvorak et
al., 199 1 ; Dolan & Adams, 1993) have concentrated on the lumbar and sacral kinematic
data with no one to date reporting on the thoracic segment displacement, velocity and
acceleration, which could be potential indicators to discriminate between healthy and
LBP people.
Thesis Outline and Purpose
To address the issues raised above in relation to the assessment and validation of
new instrumentation ( ~ a s t r a k ~ ~ ) and the efficacy of the trunk velocity rest as clinical tool
in the assessment of low back pain patients, four studies were carried out and arc
presented in the form of research papers. The aims of the first study were: a\ to assess the
static ROM of the different spinal segments; b) to assess the dynamic ROM of rhc
different spinal segments; c) to assess the repeatability and reliability of the trunk
velocity test using the 3D Space ~ a s t r a k ' ~ ~ . The second study was divided in rhree
aspects: a ) to compare two trunk velocity test protocols using the LMM; h) to comparc
~ a s t r a k ' ~ and LMM while performing the same trunk velocity test protocol; and c) to
assess whether the thoracic, thoracolumbar and lumbar segments have identifiable
differences in their patterns of movement. The third study had two objectives: a) to
address whether the thoracic, thoracolumbar, lumbar and sacral kinematic variables were
sensitive enough to distinguish between asymptomatic individuals and low back pain
subjects; and b) to investigate the association between disability scores and the thoracic,
thoracolumbar, lumbar and sacral kinematic variables. The founh study was undertaken
a) to see whether the thoracic, thoracolurnbar, lumbar and sacral kinematic variables wcrc
sensitive enough to identify subjects in an industriai population who would develop 1
back pain over the course of a two year period.
Following the presentation of all four papers, a final review of the main findil
from all studies will be presented. As well a discussion relevance of the ~ a s t r a k ~ ~ as a
measurement tool and the trunk velocity test in the assessment of low back pain patients.
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Chapter 2
Reliability and Repeatability of the Trunk Velocity Test Using the
~ a s t r a k ~ ~ '
Introduction
The high prevalence of low back pain (LBP) has been the subject of increasing
concern due not only to the high incidence, but also to the high cost ~nvolved in the
treatment and rehabilitation process. The multi factorial origin of LBP (Andersson, 198 1 )
and the limitations in diagnostic technology (CT. MRI. and x-ray) in detecting this
problem (Gracovetsky, 1990) support the fact that the clinical assessment and
quantification of LBP are still a challenge. Although early evaluation and treatment have
been reported to be successful in the reduction of the LBP incidence (Kelscy & Golden.
1988), objective evaluation and treatment outcome measures are needed to develop more
effective interventions. Disability rates are considered more meaningful i l they arc bascd
on objective measurements rather than on subjective evaluations (Hupli et al.. 1996). Thc
spine's range of motion (ROM) has been reported to be one of the most used functional
measure in the clinical setting (Mayer et al., 1995; Burton, 1997) and it has also been
used as impairment rating systems for LBP of the American Medical Association ( 1 993).
Several measurement techniques have been developed to quantify static and
dynamic spinal range of' motion. In static ROM test only the difference between the start
and the end point of motion is measured and in the dynamic ROM ail molions ;ire
measured. Although the static ROM have been more popular in clinical settings. the
dynamic ROM variables have been reported to be more sensitive in identify LBP (Manas
& Wongsam. 1986). Velocity and acceleration variables have been demonstrated to be
better able to discriminate between LBP and no LBP subjects than static range of motion
(Marras ct al., 1993; Masset et al., 1993).
X-rays have been used to assess the spinal range of motion. but this is an invasivc
technique with risk for the patient (Dvorak et al., 1991; Chiou et al.. 1996). Goniorncm-s
(Klein et al., 1991), inclinometers (Mayer et al., 1984), skin distraction (Moll & Wright.
1971 ), fingertip-to-floor (Gill et al., 1988) and photometric techniques (Gill et al.. 1988)
have also been used to evaluate range of motion. These instrumentations are frequently
used in clinical assessments mainly for static assessments.
Several different types of instrumentation have been used to evaluate the spirlal
range of motion under dynamic conditions. imaging techniques such as, cinematography
(Kumar, 1974), videography (Marras ct al., 1992) and opto-electric motion tracking
(Gracovetsky et al., 1990) have been used to capture spinal motion by tracking external
markers placed over appropriate landmarks. The disadvantages of imaging techniques are
that they are laborious to employ and their accuracy can be affected by lighting
conditions and by alignment of the camera to the subject. Isokinetic machines have also
been used to assess spinal motion (Masset et al., 1993) and arc considered highly reliable
mechanically, but some concerns have been expressed about learning effects because of
the machines and constraints on the trunk motion by the chest blocking systems (Newton
et al., 1993; Newton & Waddell, 1993). Research has shown that inclinometers (Otun &
Anderson, 1988), electronic goniometers (Boocock ct al. . 1 and !riaxlal
electrogoniometers (Lumbar Motion Monitor) (Marras et al.. 1993) provide rcliablc.
measurement of spinal motion (Adams et al., 1956; Rower et al., 1989; Marras ct 31..
1992).
The Lumbar Motion Monitor (LMM), another dynamic measurement tool, has
been used to measure performance during the trunk velocity test. To perform this test rhc
subject is asked to flex and extend the trunk in the sagittal plane as fast and as
comfortably as possible. This test was developed as a clin~cal screening tool. a
quantitative indicator of treatment progress and an indicator of readiness to return to
work (Marras et a!.. 1993). The trunk velocity test using the LMM allows thc subject to
perform free spinal range of motion without any trunk constraints, which is not possible
with an lsokinetic machine.
Electromagnetic tracking devices, such as Polhemus 1sotrakrh' and ~as t r ak '~ ' .
have been used with good reliability in the measurement of lumbar spine kinematics (An
et al., 1988; Pearcy & Hindle, 1989). but the possibility of signal distortion due to metal
interference needs to be considered (Milne et al., 1996; McGill et al., 1997) The
lsotrakrM and ~ a s t r a k ' ~ have been used to evaluated lumbar and sacral ROM in healthy
and LBP people (Pearcy & Hindle, 1989; Hindle et al., 1990) and during lifting ( D o h C1:
Adams, 1993; Nelson et al., 1995), but no study has used an electromagnetic device
during thoracic and thoracolumbar static ROM tests nor during performance of the trunk
velocity test. The ~ a s t r a k ' ~ has up to four sensors and thus i t allows the investigator to
assess not only the lumbar segment but also the thoracic and thoracic-lumbar segments.
The purposes of this study were: a) to assess the static ROM of thc dil'li'rtm
spinal segments; b) to assess the dynamic ROM of the different spinal segments; c ) to
assess the repeatability and reliability of the trunk velocity test using 3D Space ~astrak"'.
Methods
Equipment set-up
The Polhernus ~astrak"' electromagnetic motion tracking system is a device used
to the measure three-dimensional position and orientation of up to four independcnr
sensors in space. The source generates a low frequency magnetic field, which is detected
by each sensor. The system electronic unit (SEU) performs the calculaiions to compurc
the positicn and orientation of each sensor relative to the source with full six degrecs of
freedom. The rate at which data can be collected decreases as the number of' scnsors
increases. In this study the sampling rate for four sensors was 28 Hz.
The ~ a s t r a k ~ ~ accuracy is affected by the presence of metallic conductors.
whether nearby or between the source and the sensor. This can cause distortion in the
magnetic fields that affects signal reception by the sensors. The manufacturer
recommends that large metallic objects be kept a minimum of 1.83 m away tiom the
recording field and smaller objects at least twice the source to sensor distance (~as t rak '~"
3 Space user's manual, 1992).
The recording area for the trunk velocity test was approximately 50 cm' in front
of the source to reduce field distortions. Using a calibration grid developed by Day et al.
(1996) and correction software by Murdoch (1996), i t was found that no correction
algorithm was necessary for the testing location because of the proximity ot' t11c sellsors
to the source.
Subjects
Ten male subjects were involved in this study. They werc tested on two difirent
occasions. with at least two days and no more than one week between tests. Subjects
were selected according to the following inclusion criteria: healthy male subjects with
ages ranging from 20 to 30 years old. The exclusion criteria were: a history of spine cr
hip surgery, fracture, or structural deformation, and diseases that could affect motion
(rheumatoid arthritis. central nerve disorders). Before the test each subject rscc~vcd J
written and verbal explanation of the purpose and protocol of the study and signed a
consent form (Appendix 1 ).
Subject preparation followed a strict protocol in order to place the sensors o w
T1, T7, L1, and Sacrum landmarks (Figure 2.1). Landmarks were located in the following
manner: a) TI - the most prominent cervical process C7 was located and the TI was
located by counting down one vertebral spinous process. b) T7 - the most prominent
cervical process C7 was located and the subject was asked to bend fonvard, exposing thc
spinal column so that the investigator could locate T7 by counting down s e w n vertebral
spinous processes. c) L l - the iliac crests were palpated and the thumb ran horizontally
over the vertebral column allowing the palpation of the L4 spinous process. The subject
was then asked to lean over at the waist, exposing the spinal column, and the L I sp~r~ous
process was palpated. d) Sacrum - S 1 was located by counting down from the L 1
Figure 2.1 - ~ a s t r a k ~ ~ set up
process with the subject in the bent position. Once all landmarks were loccltcd and
marked, these landmark locations were checked again.
The movement of the sensors relative to the skin has been reported ro be a
concern that should be considered during subject preparation (Hindle et al.. 1990; Adams
& Dolan. 1991; Chiou et al., 1996). To minimize this problem a quick-drying tclpc
adherent was sprayed on the skin at the marker locations and once dry, a Tegaderm (3M)
transparent dressing was placed over the landmarks. Double-sided tape was used to attach
the sensors to the dressing while the sacral sensor was secured to a molded plastic pad
that was contoured to sit over the sacrum and attached with double side tape. Two strips
of elastic tape were attached over the top of the sensors in a cross diagonal shape. ' fhc
sensor wires were aligned horizontally and supported by small stirrups onto the back with
tape. This procedure, according to Dolan and Adams (1993). prevents the wircs tiom
being pulled during motion. AAer the set up the subject was asked to bend their back to
check if there was any constraint of the motion.
Test Protocols
1 - Spinal Static Range of Motion (ROM) Test
The spine static range of motion in the lateral (side to side), rotation (twisting).
and flexion (forward) directions were measured. For each direction of motion three data
collections were performed with 30 seconds rest between each data collection. The
sequence of the tests was always: flexion, lateral bending and rotation.
For flexion, the subject began by standing comfortably and then bending forward
at the waist, grasping the lower legs and pulling forward. The knees were straight and no
knee bending was permitted. The subjects were encouraged to bend as far as possihlc.
Lateral bending to the right and lefl were measured separately. Subjects began the
test in the standing position with their feet shoulder width apart. They were asksd to bend
to the right side, keeping the motion in the frontal plane and then returned to ihc starting
position. The subjects then repeated the same movement to their left side.
The rotation test was measured in the hvo directions of motion (right and left).
Subjects began the test in the standing position with the feet shoulder width apart.
Maximal twist to the right was performed and then the subject returned to the starting
position. The subjects then repeated the same movement to the left side.
2- Trunk Velocity Test
Subjects were instructed to stand with their feet shoulder width apart and their amx
crossed in front of their chest. When queued. the subject was asked to k s and cxtcnd
the trunk in the sagittal plane as fast and as comfortably as possible for 5 repetitions ( I
trial) (Figure 2.2). One repetition consisted of flexing forward then backward toward
standing. Eight trials were collected in the first day of testing and four trials wcrc
collected on the second day. Five minutes of rest was allowed at the end of each tnal.
Data analysis
A customized s o h a r e program was developed for data collection. The collected
data consisted of the three Cartesian coordinates (x,y,z) and the three Eulerian angles
(azimuth, elevation, roll) describing the position of each of the four sensors in space
relative to the source. The data were collected at 28 Hz on a Pentium computer. Residual
analysis was performed on the data to select the best filter cut-off frequency. A double
Figure 2.2 - Trunk velocity test in: A) standing position and B) flexed position
pass Butteworth filter of 4 Hz was used to filter the velocity and accelerat~on dara aficr
differentiation.
The total static spinal range of motion for flexion (just one flexion motion). right
and left lateral bending, and right and lefi rotation were collected. From the trunk velocity
test the maximum dynamic ROM flexion was considered as the higher ROM value from
five continuos flexion and extension repetitions, peak velocity, and peak accr lerat~on
were computed using the central difference technique. All these variables were computed
for the thoracic segment, thoracolumbar segment, lumbar segment (Fig. 2.3) and sacral
angle. Equations (1) to (9) illustrate how the thoracic, thoracolumbar and lumbar segment
angles were calculated for flexion, lateral bending and rotation. The tlexion angle of the
sacrum was taken as the roll angles of the sacral sensor, for lateral bending it was thc
elevation angles of the sacral sensor and for rotation the azimuth angles of the sacral
sensor. A total of 40 variables were collected for each subject during each trial.
To reduce the data for static ROM equations 1-9 were developed to examine
thoracic, thoracolumbar and lumbar segment motions during flexion, lateral bending and
rotation. The equations for these calculations are presented below. Equations 1-3 were
used to examine the dynamic kinematics during trunk velocity test. Since the motions
were primarily in sagittal plane and the motions in the other planes were small, equations
4-9 were not assessed for the trunk velocity test.
Flexion:
Thoraclc segment (8 1 ) = (roll angle sensor at L 1 ) - (roll angle sensor at T1) ( E q . 1 )
Thomcolumbar segment (82) = (roll an& sensor at T7) - (roll angle sensor at sacrum)(Eq. 2)
Lumbar segment (83) = (roll angle sensor at LI ) - (roll angle sensor at sacrum) (Eq. 3)
Figure 2.3 - Schematic to demonstrate the calculated angles A) Thoracic Segment, B) Thoracolumbar Segment, and C) Lumbar Segment
Lateral Bending:
Thorac~c segment = (elevation angle sensor at LI ) - (clevat~on angle sensor at TI ) (1:q. 4 )
Thoracolumbar segment = (elev. angle sensor at L l ) - (elev. angle sensor at I?) (kq 5
Lumbar segment = (elev. angle sensor at L1) - (elev. angle sensor at sacrum) ( E q . 6 )
Rotation:
Thorac~c segment = (azimuth anglr sensor at L 1) - (azimuth angle sensor at ) (Eq. 7
Thoracolumbar seg. = (azimuth angle sensor at L 1 ) - (azlmuth an& sensor at T7) (Eq. 8)
Lumbar segment = (azimuth angle sensor at L 1 ) - (az~muth angk sensor at sac.) ( E q . 9 )
The intraclass correlation coefficient (Icc,,~) was used to evaluate thc reliab~lity
between measurements obtained in day 1 and those obtained on day 2 lor each of the
tasks. The benchmarks for the intraclass correlation coefficients were 0.00 to 0.25 - little
or no relationship; 0.25 to 0.50 = fair degree of relationshp; 0.50 to 0.75 = moderate; and
> 0.75 = good to excellent relationship (Portney & Watkins, 1993). The mean differences
among the eight trials from the repeatability test were determined using the MANOVA
and Tukey post-hoc tests were used to identify where significant differences occurred.
These statistical analyses were conducted with the SPSS statistics package. An alpha
level of 0.05 was chosen as the level of significance.
Results
Descriptive data
Ten male volunteers having an average age of 25 k 2.8 years participated in this
study. All subjects were healthy with no previous history of low back pain. The group
had an average weight of 86 kg f 12 kg and an average height oS 1.79 m + 0.08 m. The
descriptive data for their spinal kinematic variables are reported in Table 2.1.
Repeatability
The analysis of variance showed no significance difference for the peak vclocity
and peak acceleration variables among the eight tnals performed in the same dav.
However, there was a significance difference observed for the dynamic ROM flexion
variables (Table 2.2). Tukey post-hoc testing was applied to the peak displacement and
showed that trial one was significantly different from trial two (Table 2.3) and no
significance difference was observed between trials 2 to 8. Figure 2.4 illustrate thcsc
results.
Reliability
The test-retest procedure produced reliable measurements for all variables (Table
2.4). The ICC values calculated for the spinal segments were greater than 0.91; for right
and lef lateral bending the values ranged from 0.81 to 0.88; and, for right and left
rotation the values ranged from 0.81 to 0.90. The dynamic variables of maximum ROM
flexion, velocity and acceleration had ICC values that ranged from 0.92 to 0.95. These
findings demonstrated that protocol used to perfom1 the trunk velocity test using
~ a s t r a k ' ~ had very good reliability for clinical measurements for the dynamic variables
and tbr static ROM flexion.
Table 2.1 - Descriptive data for spinal kinematic variables (N = 10)
Thoracic Thoracolumbar Lumbar Sacrum
Mean +_ SD Mean +, SD Mean f SD Mean k S I1 Static ROM Flexion (") 36 k 10 86 + 9 5 7 2 6 55, +_ S
ROM Lateral Bend. Right (") 33 + 5 47 1 6 26 i 2 13 + 5
ROM Lateral Bend. Left (") 32 k 5 46 2 4 35 5 7 I 1 ~3
ROM Rotat~on Rlght (") 42 +_ 4 3 6 + 4 1 5 5 3 y 5 3
ROM Rotrtt~on Left ( O ) 42 +_ 2 37 k 4 15 + 4 8 -t 3
Dynamlc ROM Flexion (") 32 k I5 75 k 15 45 1- 10 67 2 9
Peak Velocity ( O h ) 77 + 37 246 -t 66 125 + 37 209 + 43
Peak Acceleration (01s') 678 _+ 283 1480 + 551 7 1 7 2 2 7 7 1069k47.1
Table 2.2 - Repeatability of the trunk velocity test using MANOVA (N = 10)
Variables p-value
Thoracic Segnrent
Maximum ROM Flexion 0.026"
Peak Velocity 0.938
Peak Acceleration 0.963
Thoracolumbar Segment
Maximum ROM Flexion < 0.0005*
Peak Velocity 0.776
Peak Acceleration 0.978
Lumbar Segment
Maximum ROM Flexion 0.006*
Peak Velocity 0.808
Peak Acceleration 0.88 1
Sacral Angle
Maximum ROM Flexion < 0.0005"
Peak Velocity 0.335
Peak Acceleration 0.98 1
* p < 0.05, trials significantly different
Table 2.3 - Repeatability of the trunk velocity rest: Tukey's HSD test. Trial 1 X trial 2 iPI = 10)
Dynamic ROM Flexion p-value .-
Thoracic Segment 0.033
Thoracolumbar Segment
Lumbar Segment
Sacral Angle 0.009
Max~rnurn ROM Flexron - Thorauc Segment
I Maximum ROM Flexion - Thoncolumbar Segment
-..--------.-. . .. . . _ _ _L_.l_l._L-L_U-.-------~ . - .. -- .
Maximum ROM FIexlon - Lumbar Segment
I Marlmum ROM FIoxlon Sacral Anglo
Figure 2.4 - Comparison of peak ROM flexion values and standard deviation bars on day one for trial one through eight A) thoracic segment, B) thoracolumbar segment, C) lumbar segment, and D) sacral angle
Table 2.4 - Intraclass Correlation Coefficients (ICC) for spinal kinematic variables
Thoracic Thoracolumbar Lumbar Sacrum
Static ROM Flexion 0.92 0.9 1 0.92 0.9 1
ROM Lateral Bending Right 0.87 0.82 0.85 0.88
ROM Lateral Bending. Left 0.86 0.81 0.86 0.86
ROM Rotation Right 0.86 0.89 0 .S6 0.8 1
ROM Rotation Left 0.84 0.87 0.86 tliW
Dynamic ROM Flexion 0.93 0.92 0.94 0.93
Peak Velocity 0.9 3 0.95 0.95 0.93
Peak Acceleration 0.93 0.94 0.93 0.93
Discussion
Descriptive data
The ~ a s t r a k ' ~ ' variables for static and dynamic spinal motion showed, in general,
a very good agreement with the data reported by other scientific studies. Table 2.5 S ~ O N s
the lumbar segment maximum ROM flexion, lateral bending and rotation values assesscd
using different instrumentation. The ~ a s t r a k ~ ~ values for the lumbar ROM flexion wrrc
in agreement with several studies that used x-ray to quantify the lumbar ROM. Sincc x-
ray is considered a valid measure of spine ROM (Pearcy et al., 1984; Chiou et ul., 1996).
the ~ a s t r a k ~ ~ has face validity. The authors of the two lsotrakrM studies. who reported
high values for the ROM flexion, agreed that their values exceeded the normal values
reported (Pearcy & Hindle, 1989; Hindle et al., 1990). Hindle et al. (1990) suggested that
exaggeration of the true flexion lumbar movement resulted from a looss atrachmenr of'
markers to the skin. Hindle et al. (1990) did not report this problem in the lumbar lateral
bending and rotation results where the results are in agreement with the present study. A
different method of attaching sensors was used in this protocol, a factor which may have
avoided errors resulting from loosening of attachments. The sacral angle for the static
ROM flexion values in the present study agreed with the findings of other researchers
(Table 2.5). The thoracolumbar rotations in the present study (36" f 4" right, 37" + 4" left)
also showed similar results when compared to goniometer (38" + 5" right, 38" i 8' left)
and Isostation BZOO (34" + 6" right, 35" k 6" left) (Dillard et al., 1991).
The lumbar segment dynamic ROM flexion values were in agreement \ttith othcr
studies (Table 2.6). The only exception was from McGregor et al. (1995) who reported
much higher values. They used a triaxial potentiometric system that was attached to the
Table 2.5 - Comparison of static ROM values for spinal motions between current study and the scientific literature
Lumbar Lumbar Lumbar Sacral Instrumentation Flexion Lateral Bending Rotation Flexion
Mean (SD) Rlght Left Right l.cft %Itan Mean (SD] (SD)
~astrdk"'' - Present
study
~as trak ''! (Porter
& W llkinson, 1997)
lsouakT" (Pearcy 6r
Hindle, 1989)
lsoaakTM (Hindle et
31.. 1990)
lsonakr" (Dolan &
Adams, 1993)
lsonakn' (Nelson et
d., 1995)
Inclinometer (Kleln
et al., 1991)
X - Ray (Pearcy et
al. , 1984)
X - Ray (Ch~ou et al
1996)
X - Ray (Mayer et
a]., 1984)
X - Ray (Adams &
Hutton, 1986)
Video (Chiou et al.,
1996)
Isokinetic (McIntyre
et al., 19W)
Only male results were used in the comparison
Table 2.6 - Lumbar segment dyn.mic ROM flexion and velocity
Instrumentation ROM Velocity Mean (SD) Mean (SD)
Degree Depre r :~
~ a s t r a k ~ - Present study 45 (10) 125 (37)
Triaxial Potentiometric System (McGregor ct 60.3 (10.8) 47.7 ( 17.5)
al., 1995)
Opto-electronicDevise (Escola et al.. 1 996) 40 (14.1) 41.8 (12.6)
Electro-Goniometer (Marras & Wongsam, 43 120
Only male results were used in the comparison
subject via two harnesses positioned around the chest and pelvis. The attachment ot the
device at chest level suggested that motion recorded might be more representative of the
thoracolumbar segment than the lumbar segment alone. The lumbar velocity values were
similar to the findings reported by Marras and Wongsarn (1986) but disagreed with the
values reported in the other studies (McGregor et al., 1995; Escola et al., 1996). -4
difference in protocol was the main reason for this disagreement. In the present and
Marras and Wongsam (1986) studies. subjects were asked to perform the test as F~st as
they could whereas subjects in the other studies were asked to move in a comfbrtablc
manner throughout their flexion range of motion.
The thoracolumbar velocity values from this study were higher than Marras ct al.
(1994) and in agreement with Gill & Callaghan (1996) (Table 2.7). Differences in
protocols could account for these differences. In Marras et al. (1994) a monitor was
placed in fiont of the subjects showing a target zone. During the test the subjects were
asked to flex and extend their trunks repeatedly in sagittal plane as fast as possible, while
keeping the monitor's transverse plane position indicator within the target zone. Subjec~s
had to watch the monitor at all times during testing and if the transverse plane position
indicator fell outside the target zone, a tone would sound and the trial would bc
terminated and was repeated. Looking at a monitor during the test might slow the
subject's motion. This would explain the lower values for the kinematic variables
reported during the Marras et al. (1994) trunk velocity test. In the current study and the
Gill & Callaghan (1996) study, subjects were asked to flex and extend their trunks
repeatedly in sagittal plane as fast as possible but no visual feedback was given to the
subjects.
Table 2.7 - Thoracolumbar segment dynamic maximum ROM flexion, velocity and acceleration
Instrumentation ROM Velocity Acceleration Mean (SD) Mean (SD) iMcm (SD)
Degwes Dcgees/s ~egrees is ' Fastrak - Present study 75 (15) 246 (66) 1480 (551)-
LMM (Marras et al., 1994) 40.3 (14.9) 104.84 (17.5) 452.1 (261 2 )
LMM (Gill & Callaghan. 1996) 75.6 (8.7) 223.5 (45) 1 139.7 (279)
Only male results were used in the comparison
Repeatability
The results showed that the protocol as measured with the Fastrak'." can be used
with good repeatability for assessment of static spinal ROM and the dynamic maximum
ROM during flexion when the first trial of trunk velocity test is not considered. These
results agreed with other repeatability studies which used different devices to clssess
standardized spinal mock ups and human spinal ROM. Pearcy and Hindle f 1 4W), r~sinz
the lsotrak and wooden wedges of different inclinations that simulated the spinal motion.
found a total RMS error of less than 0.2 degrees for the repeatability of flexion-extension.
lateral bending, and axial rotation movement. Good results were also found for the
repeatability test during simulation of three dimensional rigid-body rotation using this
same magnetic tracking device connected to a three dimensional joint simulator (An et
al.. 1988). Using human subjects, the single sensor lsotrakrM device was found to be
repeatable when testing the three dimensional range of the cervical spine (Trott et al..
1996). In the Tron et al. (1996) study four trials were collected to assess repeatability and
they observed that for the first cervical flexion motion trial there was significant different
from the other three repetitions. They suggested that the poor repeatability between the
first and second trial may have been due to a lack of familiarization with the test protocol.
Lower values in the first trials were also observed in the present study for the thoracic.
thoracolumbar, lumbar and sacral maximum ROM flexion. This trend was also obsented
in repeatability studies using isokinetic machines (Smidt et al., 1983; Newton et al., 1993;
Newton & Waddell, 1993) and Lumbar Motion Monitor (Gill & Callaghan, 1996).
The trunk velocity test required that the subjects flexed lbnvard as list as
possible, However, to execute this motion, subjects had to adjust their velocity and the
amplitude of motion without losing their balance. Although they were encouraged to
practice in order to become familiar with the protocol, some subjects reported that they
felt more comfortable performing the test afler they had completed the first trial. From
these observation and the statistical results it was concluded that at least two tnals must
be collected during spinal motion evaluation, because a single trial will underestimate thc
true results. Results of the first trial should be disregarded.
Reliability
The protocol used in this study was very reliable. The ICC indicated that thcrc
was excellent reliability for sagittal plane motion ranging from 0.91 to 0.94, and good
reliability for lateral bending and rotation motion with 1CC tiom 0.81 to 0.91 (Table 2.4).
These results agreed with previous studies that used magnetic tracking devices (An et al.,
1988; DoIan & Adams, 1993; Trott et al., 1996; Porter &Wilkinson, 1997). A n el al.
(1988) reported that the lsotrakTM was a reliable tool for monitoring general spatial ngid
body. Nelson et al. ( 1993) showed ICC values ranging from 0.8 1 to 0.94 for lumbar and
pelvic range of motion for flexion, extension and sagittal lifling tasks using the isotrak""
which were close to the values observed in the current study. The reliability of full
cervical range of motion for flexiodextension, lateral flexion and rotation was also tested
using the lsotrakr" device with ICC values ranging from 0.70 to l .O (Trott et al.. 1996).
Porter & Wilkinson (1997) reported good reliability (r = 0.83) using ~ a s t r a k ' ~ to assess
lumbar ROM. In the present study the ICC for lumbar ROM yielded a value 01 0.92.
Several reliability studies have been performed to assess static and dynamic spinal
motion using different instrumentation. Table 2.8 shows a summary of the reliability
studies for the assessment of the lumbar segment static ROM. The correlation
coefficients verified that protocols, as measured by ~astrak'". had better reliability than
the other devices. Klein et al. (1991) found ICC values of 0.90 and 0.91 for
thoracolumbar right and lefi rotation using goniometer respectively. In the current s t ~ d v
the ~ a s t r a k ' ~ ylelded similar ICC values for the same motions, that is 0.89 and 0.87 i.or
the thoracolumbar right and left rotation respectively.
A possible explanation for this inferences in ICC values can be attributed to a
difference in protocol. The goniometer measurement was performed with the subject in a
sitting position and the motion was controlled by the examiner, while in the Fastrak study
the subject was tested in a standing position and free motion was allowed. Newton cY:
Waddell (1991) used Cybex inclinometer and found a good reliability (ICC = 0.89) when
sacral static ROM flexion was assessed. However, protocols with ~ a s t r a k ~ ~ were more
reliable in measuring day to day variability with ICC of 0.9 1.
Reliability coefficients to assess dynamic spinal motion were summarized in
Table 2.9. The Fastrak had better reliability than video. LlMM and electrogoniometer in
assessment of lumbar segment dynamic maximum ROM, velocity and accelemtion.
Although Marras et al. (1994) found that LMM was more rcliable than ~astrak"", the
restriction of the motion imposed by Mamas's study protocol may be the reason for the
high correlation coefficients. During the test, subjects received feedback from the
computer screen, which was used to control their motions thus making the test more
Table 2.8 - Intraclass Correlation Coefficients ( K C ) and Pearson Correlarion Coefficients (r) for static ROM lumbar segment
- --- - - ---
Instrumentation Rexion Lateral Bending Rotation Right Left Right --- Left
K C ~ast rak" " - Present study 0.92 0.85 0.86 0.86 0.S6
Doubie Inclinometers (Mein et 0.89 0.80 0.7 1
31.. 1991)
Cybex Inclinometer (Newton & 0.87 0.78 0.83
r Goniometer (Dillard et al., 199 1) 0.79 0.59 0.62 0.64 0.39
Isostation B200 (Dillard et al., 0.18 0.6 1 0.74 0.32 0.48
1991)
Only male results were used in the comparison
Table 2.9 - Reliability coefficients for lumbar segment dynamic maximum ROM, velocity and acceleration
Instrumentation Correlation ROM Vclocity Acceleration Coefficient
~ a s t r a k ~ ~ - Present study ICC 0.92 0.95 0.94
Video (Robinson et al., 1993) ICC 0.88 0.94
Electrogoniometer (McGregor et Kc 0.93 0.86
al., 1995)
LMM (Gill & Callaghan, 1996) ICC 0.87 0.87 0.69
LMM (Marras et al., 1994) Cronbach 0.96 0.96 0.95
ICC - Intraclass Correlation Coefficient, Cronbach - Cronbach Corrclat~on Coefficient Only male results were used in the comparison
likely to be repeatable. In this and other studies (Table 2.9) subjects were ticc to move
and no feedback was given during the test.
The ICC of video motion analysis in the assessment of thoracolumbar dynamic
ROM and velocity were reported to be 0.88 and 0.95 respectively (Robinson et al.. 1993 ) .
The results showed that the ~ a s t r a k ~ ~ was more reliable than video motion analysis in the
assessment of thoracolumbar dynamic ROM (ICC = 0.92) and had equal reliability for its
velocity (ICC = 0.95).
Conclusion
In this study the ~ a s t r a k ~ ~ has been proven to be capable of measuring spinal
motion statically in all planes of motion and dynamically in flexion. Kinematic values
recorded using ~ a s t r a k ~ ~ showed excellent agreement with the values published in the
literature.
The ~astrak'~ also proved to have high face validity in the assessment of static
lumbar ROM flexion. Results of the repeatability test showed that dynamic ROM flexion
tended to be lower in the first trial than the second and that no significant difference
occur from trials two to eight. This fact suggested that trial one should not be used in
spinal ROM tests. Therefore, a minimum of two trials are required to assess trunk
kinematics with only the second trial considered for analysis.
In clinical and research work, it is important that instrumentation be reliable as
demonstrated by the Fastrak in the measurement of static ROM flexion and the trunk
velocity test.
This study showed that the testing protocol is a critical factor when p e r l o r n ~ ~ n ~ -
the tnirlk velocity test. At least two normal databases have been created (Marras et ai..
1994; McGregor et al., 1995) and other studies have used different protocols to perlbrm
the trunk velocity test. Such different ways of performing the trunk velocity test may bc
one reason for the variation of the kinematics variables originated from this test, a factor
which makes it difficult to compare the results across different studies. This raises a new
research question about the importance of establishing a standard protocol to allow
comparison across studies.
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Chapter 3
Trunk Velocity Test: Comparative Study Between ~ a s t r a k ~ ~ and
Lumbar Motion Monitor
Introduction
One of the most difficult tasks associated with the treatment of the low back pain
(LBP) is its clinical evaluation. As low back pain has multiple etiologic factors, the
likelihood of identifying the specific cause in any one patient is very low, on the order of
5 to 10%, and a definite structural diagnosis can be reached in no more than 50% of the
cases (Frymoyer et al., 1980). It has been estimated that a precise diagnosis is unknown
in 80 to 90% of patients with LBP (Spratt et al., 1990). As part of the clinical evaluation a
functional assessment is one way to quantify the severity of LBP (Mayer et al., 1981;
Masset et al., 1993; Rainvilie et al., 1996).
Marras and Wongsam (1986) developed a functional test, called the trunk velocity
test, which recorded the trunk's dynamic activity and could discrimination between
healthy and LBP individuals. In recent studies, the Lumbar Motion Monitor (LMM)
device was developed to measure tmnk motion during the trunk velocity test and was
used to confirm these findings (Marras et al., 1993; Marras et al., 1994). The LMM is a
triaxial electrogoniometer that measures the three-dimensional position of the
thoracolurnbar spine with respect to the pelvis. In a study by Marras et al. (1994), a
comprehensive database of normal trunk kinematics using 35 1 healthy subjects (no LBP)
was developed using the LMM. This database could be used as a benchmark by hot},
clinicians and ergonomists in the evaluation of the Functional capacity of the spins.
Gill and Callaghan (1996) used the Lumbar Motion Monitor to measure the
thoracolurnbar range of motion, velocity and acceleration and found higher values than
Marras et al. (1994). According to Gill and Callaghan (1996), the main reason for the
difference was differences in testing protocol. In the Marras et al. ( 1 994) study, a monitor
was placed in Front of the subjects showing a target zone and during the test the subjects
were asked to flex and extend their trunk repeatedly in the sagittal plane as fast as
possible, while keeping the monitor's transverse plane position indicator within the target
zone. The subjects had to watch the monitor at all times during testing and i f their
position indicator fell outside the target zone, a tone would sound and the trial would be
repeated. In the Gill & Callaghan (1996) study, subjects were asked to flex and to extend
their trunk repeatedly in sagittal plane as fast as possible, but they were not given any
visual feedback.
An electromagnetic tracking device called ~astrak'" was also used to assess
kinematics of the spine using the trunk velocity test (Chapter 2). This study also reported
higher kinematic values than Marras et al. (1994), and like Gill & Callagharn (1996)
attributed differences to the test protocol. The test protocol used by Marras et al. (1994)
had a visual feedback system that was designed to work with the LMM, and this sottware
cannot be used by other devices. Using different protocols makes it difficult to compare
directly the Marras et al. (1994) data to other data sets using different devices than the
LMM. Therefore, it is necessary to develop a standard trunk velocity test protocol to
allow comparison of the kinematic values using different devices.
According to Mamas et al. (1995). any other device with a resolution similar to
the LMM (video, infrared, magnetic, etc.) should be able to obtain the same kinematics
measures for the trunk velocity test. So far no study has compared the LMM to another
device to measure performance of the trunk velocity test. The ~astrak'" is a good dcvicc
to compare to the LMM since i t has the advantage of having four sensors. which allows
the investigator to assess the kinematic values, not only for the thoracolumbar segment.
but also for the thoracic and lumbar segments. The ~ a s t r a k ~ " has also been reported to
have good reliability and repeatability while performing the trunk velocity test (Chapter
2).
The purposes of this study were: a) to compare two trunk velocity test protocols
using LMM; b) to compare the ~ a s t r a k ~ ~ and the LMM while performing the same trunk
velocity test protocol; c) to assess whether the thoracic, thoracolumbar and lumbar
segments have identifiable differences in their patterns of movement.
Methods
Equipment set-up and attachment
a) Lumbar Motion Monitor (LMM)
The LMM was attached to the thorax and the pelvis using rigid metal plates
(Figure 3.1). This provides two stable 'anchors', one to the middle spine and another to
the pelvis. Thus, the LMM measures the position of the thoracolumbar spins relative to
the pelvis. The thoracic section of the exoskeleton is connected via wires to three
potentiometers in the pelvis section and these potentiometers record the motion as the
exoskeleton moves forwards, backwards, or to the sides. The potentiometer signals are
Figure 3.1 - Subject set up for the Lumbar Motion Monitor: (A) Only the harness syshm. and (B) the complete set up
interfaced to an analog-to-digital converter and are recorded on a microcomputer. The
signals are then processed to determine position, velocity and acceleration of the
thoracolurnbar trunk as a functional of time. Smoothing of the signals is perfommi prior
to differentiation (Marras et al, 1992).
b ) ~ a s t r a k ~ ~
The Polhemus ~ a s t r a k ~ " electro-magnetic motion tracking system is a device
used to measure the three-dimensional position and orientation of up to [our independent
sensors in space. The source generates a low Frequency magnetic field, which is detected
by each sensor. The system electronic unit (SEU) perfoms the calculations required to
compute the position and orientation of each sensor relative to the source with thc ful l s ix
degrees of freedom.
Testing protocol
Two testing protocols were used in the present study. The protocol described by
Marras et al. (1994) was named the 'restricted test protocol' (RTP) and the other used by
Gill & Callaghan (1996) and in Chapter 2 was named the 'free test protocol' (FTP).
a) Trunk velocity test using restricted test protocol (RTP)
A monitor was placed in front of the subjects showing a target zone (Figure 3.1).
The subjects were instructed to stand with feet shoulder width apart and arms crossed in
front of their chest. When queued, the subject was asked to flex and extend the trunk in
the sagittal plane as fast and as comfortably as possible while keeping the monitor's
transverse plane position indicator within a target zone for 5 repetitions (1 trial). I f their
transverse plane position fell outside the target zone a tone sounded and the trial was
Figure 3.2 - Monitor feedback screen: (A) before test start, and (B) during the test
repeated. One repetition consisted of flexing forward then backward toward standing.
Four trials were collected, but the first trial was considered a warm up and the others
were considered for further analysis. A five minute rest was allowed at the end o t' cltch
trial.
b) Trunk velocity test using free test protocol (FTP)
The procedure for this test was the same as the test described above. The only
difference was that no feedback was provided to the subject allowing then to move frecly.
Study 1: Comparison of protocols using LMM
Fiffeen healthy male volunteers took part in this study. Before the ~ c s t each
subject received a written and verbal explanation of the purpose and protocol of the study
and signed a conscnt fonn (Appendix 2). Subjects were randomly assigned to thcir lirst
test protocol. The trunk velocity test was performed using the same steps already
described in the previous section for the RTP and for the FTP (Figure 3.3).
The LMM was attached to the subjects via a hamess system to the thorax and to
the pelvis with a rigid metal plate. This provided two stable points: the mid-spine (chest)
and the pelvis (waist). The waist harness was applied by centering the exoskeleton
attachment surface over the lumbar-sacral region of the subject, so the top edge was just
below to the LYS1 joint. It was fastened with waist and upper thigh belts to be secure,
but not excessively tight. The chest harness was applied by centering the exoskeleton
attachment plate over the thoracic region of the subject's back. The harness was secured
in a snug fashion by adjusting the velcro straps at the shoulders and the chest areas. The
lower portion of the exoskeleton was secured first in the waist harness. Prior to securing
Figure 3.3 - Trunk velocity test LMM: (A) RTP and (B) FTP
the upper portion of the exoskeleton to the chest harness. the upper portion was adjusted
until the wires between the two sections became taut and then it was secured.
Study 2: Comparison between ~ a s t r a k ~ " and LMM
Ten heaithly male subjects were involved in this study. Before the test each
subject received a written and verbal explanation of the purpose and protocol of the study
and signed a consent form. Subjects were randomly assigned to initiate the test using
either ~ a s t r a k ~ ~ or LMM. The trunk velocity test was performed according to the free
motion test protocol explained above (Figure 3.4). Since the LMM measures the
thoracolumbar motion from approximately T7 to sacrum (Gill & Callaghan. 1996) thc
~ a s t r a k ~ ~ sensors were attached at the T7 spinous process and sacrum region matching
the same thoracolumbar segment. The same set up used in the study 1 .
Subject preparation to use the ~ a s t r a k " ~ followed a strict protocol that was
described in the Chapter 2. The subject set up to use the LMM was perfomled following
the same process described in the previous section.
Data analysis
Maximum dynamic ROM flexion, peak velocity and peak acceleration values for
the thoracolumbar segment were measured and computed in the first study using only the
LMM. In the second study the same measures were done using both the ~as trak~" and the
LMM. In addition, maximum dynamic ROM flexion, peak velocity and peak acceleration
values for the thoracic segment, lumbar segment and sacral angle were measured using
the as trakTM.
Figure 3.4 - Trunk velocity test free test protocol: (A) using ~astrak'" and ( B ) using LMM. These tests were perfomled separately because the LMM metal hamcsss interkrcd with the FASTRAK measurements.
Three trials of data were collected and averaged for each subject. A paired student
t-statistic and a Pearson product-moment correlation were used to compare the kinematic
values for the restricted and trunk velocity test using LMM and 10 compare the Fastrak'"
with the LMM while using the free test protocol. The benchmarks for interpre~atlon of
the Pearson correlation coefficients were 0.00 to 0.25 = little or no relationship; O . Z j LO
0.50 - fair degree of relationship; 0.50 to 0.75 = moderate; and > 0.75 = good to excel lent
relationship (Portney & Walkins, 1993).
In study 1 , a regression analysis was performed on the thoracolumbar segment
variables to generate repression equations that would predict the trunk velocity variables
for the restricted test protocol from the trunk velocity variables using the lrce test
protocol. This statistic was conducted to determine the predictive power of the Mar~al
free style protocol to the Marras et al. ( 1 994) protocol.
In the study 2, a Pearson product-moment correlation was also used to assess
whe:her the thoracic, thoracolumbar and lumbar segment had the same variation in their
kinematic variables. In this analysis the data of the three trials were not averaged, but
treated independently. These statistical analyses were conducted with the SPSS statistical
package. For all statistic analyses a significance level of p c 0.05 was adopted.
Results
Study 1: Comparison of protocols using LMM
The fifteen male volunteers had an average age of 30 +_ 8 years, height of 1.74m i.
0.2 m., weight of 85.3kg + 12kg and were all healthy subjects with no previous history of
low back pain. The descriptive data showed that the means for the maximum ROM
flexion, peak velocity and peak acceleration were higher using the FTP than the RI'P.
The RTP trunk velocity test had a reduction to approximately 61% in the ROM when
compared to FTP. Excellent correlations between RTP and FTR were observed for all
variables with values greater than r = 0.85. These findings are summanzed in Table 3.1.
The scatterplot for the maximum ROM flexion, peak velocity and pcak
acceleration illustrated the positive linear relationship between the RTP and FTP
variables (Figure 3.5).
Regression equations (Eq. 1, 2, 3) were calculated to predicted maximum KOM
flexion, peak velocity, and peak acceleration when using RTP From the same variables
when the trunk velocity test was performed using FTP. Statistic data for the equations arc
listed in the Appendix 3.
Maximum ROM flexion RTP = 0.453 * maximum ROM flexion FTP + I 1 .OJ ( E q . 1 )
Peak velocity RTP = 0.186 * peak velocity FTP + 69.93 (Eq . 21
Peak acceleration RTP = 0.397 * peak acceleration FTP - 66.57 (Eq, 3)
Study 2: Comparison between ~ a s t r a k ~ " and LMM
Ten male volunteers having an average age of 25 +_ 2.8 years participated in this
study. The group had an average weight of 86 kg f 12 kg and an average height of 1.79
No significant differences were observed between the kinematic variables from
trunk velocity test performed using the ~ a s t r a k ~ ~ and the LMM. Excellent correlations
were also observed between the variables measured by the two devices. These data are
reported in Table 3 -2. The results suggested that both ~ a s t r a k ~ ~ and LMM can be used
to assess the trunk velocity test when the observer is interested in only peak values.
Table 3.1 - Comparison of protocol using LMM - descriptive data and Pearson product- moment correlation. (N = 1 5 )
-- . - - - - - -- --
LMM (RTP) LMM (FTP) p - value* r**
Mean k SD Mean k SD Maximum ROM Flexion (") 43 f 7 69k13 <0.0005 0.86
Peak Velocity (*/s) 1 1 2 f 14 224 + 64 < 0.0005 0.87
Peak Acceleration ('I?) 450 2 180 1322 2 397 < 0.0005 0.87
* Assoc~ated with Paired Student t-statistic * * Associated with Pearson product-moment correlation
Ma mmum ROM LMM Free Protocol
Peak Velouty LMM Free Prolocol
Peak Acceleration Free Protocol
Figure 3.5 - Correlation between trunk velocity test protocols: The regression line and the 95% confidence interval bands are shown for (A) maximum ROM flexion, (B) peak velocity, and (C) peak acceleration.
Table 3.2- Comparison between ~ a s t r a k ~ " and LMM - descriptive data and Pearson product-moment correlation. (n = 10)
~ a s t r a k ~ " LMM p - value* r**
Mean k SD Mean k SD Maximum ROM Flexion (") 75k 15 70 k 13 0.254 0.92
Peak Velocity ( O h ) 246 + 66 232 + 74 0.377 0.92
Peak Acceleration (01s.') 1480 + 551 1322 + 451 0.101 0.53
* Associated with Paired Student t-statistic ** Associated with Pearson product-moment correlation
Table 3 .3- Descriptive data for spinal kinematic variables from ~astrak''"
Thoracic ~horacoiurnbar Lumbar Sacrum (TI - L1) (T7 - S1) (L1 - S1) (S1) Mean i SD Mean k SD Mean k SD Mean .t SD
Maximum ROM Flexion (O) 32 + 15 7 5 + 15 45+ 10 67 +_ 9
Peak Velocity ("Is) 77 + 37 246 + 66 125 -4 37 209 2 43
Peak Acceleration ('/s2) 678 + 383 1480F551 7 1 7 k 2 7 7 1069-t474
Maxlrmrn ROM Lumbar Segment
Peak Velwty Lumbar Segment
Peak kceleration Lumbar Segment
Figure 3.6 - Thoracic and lumbar segments kinematic correlations: (A) maximum ROM
flexion, (B) peak velocity and (C) peak acceleration.
I nma I
Figure 3.7 - Representative examples of dynamic ROM flexion thoracic, thoracolumbar, lumbar segments and sacral angle for two subjects (A and B)
Table 3.4 - Pearson Correlation Coefficients (r) for spinal kinematic variables
- -
Thoracic ~horacolumbar Lumbar Sacrum
Thoracic Max. ROM Flexion 1 .OO
Thoracolumbar Max. ROM Flexion 0.77** 1 .OO
Lumbar Max. ROM Flexion 0.23 O X * * 1 .OO
Sacral Max. ROM Flexion 0.45 * 0.2 1 0.35 1 .OO
Thoracic Peak Velocity 1 .OO
Thoracolumbar Peak Velocity 0.78** 1 .OO
Lumbar Peak Velocity 0.24 0.53** 1.00
Sacral Peak Velocity 0.50** 0.24 0.14 1 .OO
Thoracic Peak Acceleration 1 .OO
Thoracolumbar Peak Acceleration 0.61** 1 .OO
Lumbar Peak Acceleration 0.09 0.5 1 ** 1 .OO
Sacral Peak Acceleration 0.64* * 0.504* 0.30 1 .OO
* Correlation is significant at the 0.05 level ** Correlation is significant at the 0.01 level
but they were significantly different. Lower kinematic values were observcd \s hen thc
RTP was used, suggesting that a restriction of the spine's range of motion occurrcd
during the test.
The trunk velocity test using the RTP yielded values that agreed with Marras et al.
(1994) for the maximum ROM flexion, peak velocity and peak acceleration (Figure 3.8).
These results were expected since we used the same protocol as did Marras et al. ( 1 994).
Gill & Callaghan (1996) also used the LMM to perform the trunk veloclty test. but i n
their study the free test protocol was used. Their kinematic value results were similar to
the values found in the present study (Figure 3.9). These findings support the theory that
differences in results between Marras et al. (1994) and Gill & Callaghan (1996) study and
the study presented in Chapter 2 were due to the differences In protocols.
Using the LMM the investigator has the choice between the two-test protocols.
The RTP was designed to limit any secondary rotation or side bending motion during the
test and, consequently, imposed some limitation in the range of motion. On the other
hand, the FTP allowed the subject move naturally throughout hls flexion ROM. The RPT
has the advantage of allowing the investigator to compare resuits to the normal database
created by Marras et al. (1994), which provides the maximum ROM flexion, peak
velocity and peak acceleration values for the thoracolumbar segment of the spine.
However, the FTP may be a better choice when performing the trunk velocity test. Since
the spine is a complex three-dimensional structure movement in any one plane is always
accompanied by some movement in the other two planes (Pearcy & Hindle, 1989). These
secondary motions were reported to be small during flexion ROM of the spine with no
effect in the overall pattern of the motion (Pearcy et al., 1984; Pearcy & Hindle, 1989).
0Marrasetal 119941
.Present Study
Dynamic ROM Flexon
- - - - - - - - - - - - - . . - - - - - - - - - -
Trunk velocity test RTP
Y, 100 (
8 2 ' m O M arras ct at ( I 994) 0, ~
so 1 P r e s e n t Study
B : O i ---
I h a k Vekcrty
-- - .- I
Trunk velocity test RTP
Peak Acceleration
M arras el al ( 1994)
a P resent Study
L -- -- -- - - p--~--~p
Figure 3.8 - Comparison of the kinematic variables between studies that used RTP to perform trunk velocity test. (A) Dynamic ROM flexion, (B) Peak velocity, and (C) Peak acceleration
, 100 .
80 . UGJI & Callaghan (1996)
N P resent Study
1 20 ; I 1 0- --. A i
Dynamc ROM Flexion
[S~GIII L Callaghan (1996)
.P rcscnt Study
k a k Vebctty
t I Trunk velocity test FfP
FBak Acceleration
nG~ l l& Callaghan (1996)
P nsent Study
Figure 3.9 - Comparison of the kinematic variables between studies that used FTP to perform trunk velocity test. (A) Dynamic ROM flexion, (B) Peak velocity, and (C) Peak acceleration
Since the purpose of the trunk velocity test is to evaluate the spinc's functionul
capacity the results might be useful in determining i f a subject should return to his norn~al
activities after a period of low back pain. These normal activities may demand a spinal
ROM greater than those allowed using RTP, which could lead to errors in the functional
assessment of the subject. Another important point in favor of the FTP that is according
to Mamas et al. (1995), the RTP could not be used with other device since it would be
difficult to provide the same type of feedback that one designed into the LMM. This F~ct
may be a major limitation in the use of the RTP since so many devices such as
electrogoniometers, electromagnetic tracking devices, opto-electric motion tracking
deviscs and video motion analysis have the potential to be used to assess the trunk
velocity test.
Mamas's database was created based on a trunk velocity test using the RTP. In
order to investigate potential of using the same database for the FTP, regression equations
were created to predict the results of the RTP when using the FTP. Although these
equations are based only on men with ages ranging from 20 to 40 years, it would appear
that there is potential to convert the relationship to a new database created using the FTP.
Further research would be needed to determine the efficacy and importance of this
transformation.
Study 2: Comparison between ~ a s t r a k ~ ~ and LMM
The results of this study showed no significant difference in the kinsmatic
variables of the trunk velocity test when the same protocol was applied using the
l%strakTM and the LMM. Excellent correlation was observed between the ~astrak'." and
LMM for maximum ROM flexion. peak velocity and peak accelcration. Figurc 2 1 0
shows that Gill & Callaghan (1996) reported similar results for the maximum Kohl
flexion and the peak velocity when compared with the present study. Thcir peak
acceleration values were lower than this study. but within one standard deviation of this
study. These results gave support to the Marras et al. (1995) statement that any other
device should be able to obtain the same kinematics variables for the trunk velocitv test.
This findings also support the fact that the differences in the kinematic valucs horn t h ~
trunk velocity tests when compared with Marras's database and Chapter 2. were mainl).
due to difference in protocols and not due to the use of a device other than LMM.
The ~as t r ak '~ ' showed the same ability as the LMM to assess thc trunk pcak
velocity kinematic variables and also showed that it could provide more information than
the LMM. The present study showed that the ~ a s t r a k " ~ allowed assessment not only the
thoracolumbar kinematic variables but also the thoracic segment, lumbar segment and
sacral angle variables, thus giving it an advantage over the LMM. The low correlations
observed between the variables among different spinal segments suggested that each
segment contributed differently during the dynamic ROM flexion trials. Pcarcy S:
Hindle(1989) and Marras et al. (1993) both hypothesized that the spine's rno~ion
contained a large amount of information about the status of the spine's musculoskeletal
control system and that it could generate different patterns of spinc movcrnents
("motion signature"). The present study observed different recruitment of the spinal
segments with different motion characteristics for each segment during the trunk velocity
test. This fact suggested that further research is needed to study the functional assessment
- - -.- - -
Trunk velocity test FTP 100 .
0 Present sludy LM M
MGdI & Callanghan ( 1996)
aPresenl study Fastrak
7 -- - -- - - - .- -
I Trunk velocity test FTP
Present study LM M ,
~ G I I I 8 Callanghan (1996) '
OPresenI study Fastrak
-. - - - . - . - - - . 1 Trunk wlodty test FTP
0 Present study LM M
aOH B Callnnghan ( 1996)
aPreserrt study Faslrak
Figure 3.10 - Trunk velocity test kinematic variables comparison between studies that used free test protocol. (A) Dynamic ROM flexion, (B) Peak velocity, and (C) Peak acceleration
of the spine in healthy and low back pain subjects focusing on h e specific pcrl'orniancc
and contribution of the thoracic. thoracolurnbar, and lumbar segments and the sacral
angle.
Conclusion
The present study showed that a free test protocol could be used Tor the trunk
velocity test, since it can be used with devices other than just the Lumbar Motion Monitor
and allowed the subjects to perform the trunk velocity test using their total spinal range of
motion.
The ~ a s t r a k ' ~ provides comparable information to the LMM in the assessment o i
the trunk vclocity test in terms of peak values and these devices could bc uscd
interchangeably. The ~astrak'" also has the advantage of providing kincrnatlc valucs not
only for the thoracolumbar segment, but also for the thoracic segment, lumbar segment
and sacral angle. Future research within the trunk velocity test should be directed toward
a better understanding of the different pattern of motion observed during the trunk
velocity test as curve shapes suggest that each segment of the spine probably has its own
motion signature carrying with it specific kinematic information.
References
1 . Frymoyer J W, Pope MH, Costanza MC: Epidemiologic studies of low back pain. Spine 5:419-423, 1980.
2. Gill KP, Callaghan MJ: Intratest and intertest reproducibility of the lumbar motion monitor as a measure of range, velocity and acceleration of the thoracolumbar spine. Clinical Biomechanics 1 1 :4 18-42 1, 1996.
3. Marras WS, Wongsam PE: Flexibility and Velocity of the Normal and Impaired Lumbar Spine. Archives of Physical Medicine Rehabi[italion 6 7 2 1 3-2 1 7 . 1986.
4. Marras WS, Fathallah FA, Miller RI, Davis SW, Mirka GA: Accuracy of three- dimensional lumbar motion monitor for recording dynamic trunk motion characteristics. henlutional Joltnral of hdtcsrrial Ergo~lon~ics 9: 75 -87. 1 99 2
5. Marras WS, Parnianpour M, Ferguson SA, Kim JY, Crowell RR, Simon SR: Quantification and classification of low back disorders based on trunk rno tion. Eurcpcm Journaf of Phpicol M d i c i ~ l r Rrlr~lliiiifrrfruri 3 .Z i 6 - 2 3 5 , i 993.
6. Marras WS, Parnianpour M, Kim JY, Ferguson SA, Crowell RR. Simon SR: The effect of task asymmetry, age and gender on dynamic trunk motion characteristics during repetitive trunk motion characteristics during repelitivc trunk flexion and extension in a large normal population. lEEE Trausocrions 011
Rehabilitation Engineering 2 : 1 3 7- 146, 1994.
7. Marras WS, Pamianpour M, Ferguson SA, Kim JY, Crowell RR. Simon SR: Truuk motion characteristics as a quantitative measure of low hack disorder recovery status. Proceedings ojMe I2th IErl 3:79-8 1, 1994.
8. Marras WS, Parnianpour M, Ferguson SA, Kim JY, Crowell RR, Bose S. Simon SR: The classification of anatomic- and symptom-based low back disorders using motion measure models. Spine. 20:253 1-2546. 1995.
9. Masset D, Malchaire J, Lemoine M: Static and dynamic characteristics of the trunk and history of low back pain. International Journal of Industrial erg on on tic:^ 1 1 :279-290, 1993.
10. Mayer TG, Tencer AF, Knstoferson S, Mooney V: Use of noninvasive techniques for quantification of spinal range of motion in normal subjects and chronic low back pain dysfunctional patients. Spine 9588-595, 1984.
I 1. Pearcy MJ, Ponek I, Shepherd J: Three-dimensional x-ray analysis of normal movement in the lumbar spine. Spine 9:294-297, 1 984.
12. Pearcy MJ, Hindle RJ: New method for the non-invasive three-dimensional measurement of human back movement. Clinical Biomechanics 4:73-79, 1989.
13. Porter JL, Wilkinson A: Lumbar-hip flexion motion: A comparative study between asymptomatic and chronic low back pain in 18- to 36-year-old men. Spine 22: 1508- 15 14, 1997.
11. Rainville J, Sobel JB, Banco RJ, Levine HL, Childs L: Low back and cervical spinc disorders. Orthopedic Clinics of North A~?lerica 27:729-746, 1996.
1 Spratt KF, Lehman TR, Weinstein JW: A new approach to low back examination: Behavioral assessment of n~echanical signs. Spine 1996- 101. 1990.
Chapter 4
The Use of the Trunk Velocity Test in Healthy and
Low Back Pain Subjects
Introduction
Low back pain (LBP) is one of the most common problems that leads to medical
attention in a primary care institution and a significant cause of lost work time and
disability (Frymoyer et al., 1980; Andersson, 198 1; Erdil et al.. 1997). 11 has bccn
associated with many risk factors of occupa~ional and non-occupational origin and is self-
limited in nature. Fifty-seven percent of the LBP cases resolve within one week, 90% in
six weeks, and 92 to 95% after twelve weeks. The remaining 5 to 8% will present a
persistent pain for six months or more and may progress to a chronic phase (Nachemson
& Bigos, 1984; Bishop et al., 1997). Less than 50% of the chronic group will be able to
return to work (Hazard et al., 1991; Magnusson et al., 1998) and they will account for
80% of the workers' compensation costs (Spitzer et al.. 1987; Erdil et al.. 1997). Thc
underlying pathophysiology for the vast majority of patients with LBP is unknown in
80% to 90% of the cases (Bergquist-Ullman & Larsson, 1977; Spratt et al.. 1990).
The rnultifactorial nature and the difficulty in reaching a clear diagnosis have
challenged health professionals to intervene efficiently and decrease the disability and
costs associated with LBP. A clear diagnosis is important in planning treatment and
monitoring patients especially when it is necessary to evaluate whether a patient's
condition has changed following a treatment or i f he/she is ready to return to work. .A
variety of clinical tools have been used to assess impairment and functional limitations
related to LBP and to attempt diagnosis of the problem. However, all of them present
limited interpretation of the outcomes. The sophisticated imaging technologies such 3s
magnetic resonance image (MRI), computed tomography (CT), myelography. and X-ray
are able to identify a problems in fewer than 15% of the cases (Nachemson. 1985). The
pathoanatomic findings are poorly correlated with low back complaints. suggesting that
abnormal anatomy may not be related to the patient's symptoms (Bishop el al., 1997).
Evaluation using information from the history of the problem and from physical
assessment is also compromised by the unclear relationship between the clinical history
and physical findings (McGregor et al., 1998).
Disability questionnaires, which often include questions concerning symptom
severity and functional limitations, have also been used in the clinical settings to cvaluatc.
LBP. The Functional Rating Scale (Evans & Kagan, 1986), the Roland-Moms
Questionnaire (Roland & Morris, 1983; Stratford & Binkley, 1997; Stratford et al.. 1998),
the Oswestry Questionnaire (Fairbank et al., 1980; Mellin, 1988; Hazard et al.. 1991 ;
Escola et al., 1996), and the Lower Extremity Functional Scale (Binkley. 1999) arc
examples of self-reported instruments used to assess disability related to LBP. 'Thrsc
questionnaires provide outcome measures of the patients' perception of their functional
status, but the results must be interpreted carefully. Self-rcported measures may be
subject to a perceptual or belief mismatch; there may be diffcrcnces bctwecn how
patients function and how they believe they function (Fordyce et al., 19841, and there
may be differences in what the patient reports and in what the esaminer concludes
(Simmonds et al., 1998).
Despite all controversies. the physical assessments have been used nlore
frequently to evaluate LBP individuals as they provide more objective measurements
(Triano Sr Schultz, 1987), and they are seen by the health care providers as more valu;lblc
than self-reported measures (Mayer et al., 1997). The trunk strength test (Bienne-
Sorensen, 1984; Mein et al. 199 1 ; Ito et al., 1996), the straight leg raising test (Wolf et
al., 1979; Biering-Sorensen, 1984; Thomas et al., 19881, and the spinal range of motion
are some of the physical tests most frequently used to assess low back pain.
The trunk strength test requires that the patients sustain a maximal volun~arv i'orcs
against a resistance. This test may be associated with a nsk of injury (Biering-Sorensen.
1983) and its results can be affected by the patient's fear of pain during a maxlmum cSfm
(Hupli et al.. 1996). The straight leg raising test is used to measure hamstring
musculotendinous length and its association with low back pain, but its value has been
questioned (Wolf et al.. 1979; Bohmnon, 1982; Waddell et al., 1992). Contradictory
results regarding the ability to identify LBP patients using spinal range of motion (ROM)
have been reported (Biering-Sorensen, 1984; Masset et al., 1993). although this
procedure has been recommended by the American Medical Association as a mcasurc to
evaluate low back pain impairment (AMA, 1990). Biering-Sorensen ( 1984) and Mclntrye
et al. (1991) reported that LBP subjects had restricted spinal motion, which suggested
that abnormal motion may be an indicator of abnormal spinal mechanics and may bc
associated with low back pain (McGregor et al., 1998).
The use of continuous dynamic profiles of motion with higher order derivatives
was introduced by Marras & Wongsam (1986). In their study, velocity variables \trcrc
reported to be more sensitive in the identification of LBP than static ROM measures. This
I'xt was later confirmed by other studies, which introduced another variahlc.
acceleration. as a good indicator of LBP (Mclntyre rt al.. 1991; Masset ct 31.. \~p)?;
Marras et al.. 19951. To date. studies of spinal motion using higher order derivatives h z \ ~ ?
evaluated the lumbar region and thoracolumbar region of the spine, but only thc
thoracolumbar segment has been studied.
The use of the ~ a s t r a k ~ ~ , an eiectomagnetic tracking device, in the dynamic
assessment of spinal motion (Chapters 1 and 2) introduced the possibility of study in^
several spinal segments simultaneously. The study of the thoracic, thoracolumbar, lumbar
and sacral regions of the spine while performing flexion-extension dynamic motion
showed that different patterns of motions occurred in each segment of the spine.
suggesting that each segment has a specific motion profile (Chapter 3). This finding
raised the question of how these motion profile differences in the specific regions of the
spine presented by asymptomatic individuals compare with the motion profiles of low
back pain individuals. ROM has been reported to be poorly correlated with disability
measure (Waddell et al., 1992; Simrnonds et al., 1998), however, it is not known how
velocity and acceleration variables correlate with disability.
The purposes of this study were: 1 ) to determine whether the thoracic.
thoracolurnbar, lumbar and sacral kinematic variables were different bctwcen
asymptomatic individuals and low back pain subjects; and 2) to investigate the
association between disability scores and the thoracic. thoracolumbar, lumbar and sacral
kinematic variables.
Methods
Subjects
Healthy and low back pain suffering volunteers were recruited from the Kingston
area through posted advertisements, Queen's University newspaper, and physiotherapist
referral. Preliminary screening was done through an informal telephone interview when
the inclusion and exclusion criteria were checked. The inclusion criteria for the healthy
subjects were: males, ranging in age from 20 to 60 years. The exclusion critena werc: did
not have low back pain and/or hip pain in the last two years. no history of low back pain
that required medical attention, no restricted or lost work duties due to LBP in thc past
two years, no history of spine or hip surgery, or fracture, and no diseases that could affect
motion (rheumatoid arthntis, central nerve disorders). The inclusion criteria for low back
pain subjects were: males ranging in age from 20 to 60 years with at least a two-month
period of having low back pain. The exclusion criteria for the LBP group were: history of
spine or hip surgery or fracture, and diseases that could affect motion (rheumatoid
arthntis, central nerve disorders). Before the test started. each subject received a wristen
and verbal explanation of the purposes and protocol of the study and signed a consent
form (Appendix 4).
Questionnaire and Pain Scale
The LBP subjects were asked to answer the Oswestry Low Back Pain D'
Questionnaire to assess their level of disability (Fairbank et a]., 1980). This quest
consisted of ten questions designed to assess limitations in various activities ol' dailv
living. The activities covered included pain intensity, personal care. liliing, walklng.
sitting, standing, slipping. sex life. social life, and travelling. The Oswrstry questionnaire
was given because of its simplicity, internal consistency, and high test-retest reliability
(Triano & Schultz, 1987). The maximum score possible (50 points) represented disability
severe enough to require the individual to remain in bed, whereas zero points represented
no disability at all. The scores were calculated by dividing the raw score by the total
possible score and then multiplying by 100. The final scores were interpreted 3s ;l
percentage of the subjects' perceived disability pain (Fairbank et al.. 1980).
A pain scale ranging from 0 to 10 was used to rate the presence of pain before and
after the test, where zero represented no pain and ten represented extremely intense pain
(Appendix 5). A short questionnaire to gather some work characteristics information
from the subjects were also applied before starting the test (Appendix 6).
Trunk Velocity Test
Subject preparation to use the ~ a s t r a k ~ ~ followed the procedures described in
Chapter 2. The trunk velocity test was performed using the free test protocol that was
reported in Chapter 3. Two trials with five repetitions each were collected for each
subject but only the second trail was considered in the analysis. The first trial was used as
a warm-up. Maximum dynamic ROM flexion (the higher ROM value from five continuos
tlexion and extension repetitions) was measured while peak velocity and psak
acceleration values were computed for the thoracic segment, thoracolumbar segment.
lumbar segment and sacrum.
Data analysis
The Oswestry Disabilitv Questionnaire was analyzed in accordance with its own
guidelines. Subjects with score from 0% to 20% were cons~dered to have minimal
disability, 20% to 40% moderate disability, 40% to 6094 severe disability, 6046 to SO%,
crippled, and 80% to 100% bed-bound or exaggerated. (Fairbank et a]., 1 980). For the
purpose of this study the low back pain subjects were divided into two groups: a
moderate LBP group (MLBP) that scored less than 40% in the disability questionna~re
and a severe LBP group (SLBP) that had equal to or greater than 40% disability scores.
To determine whether the three groups (healthy, moderate LBP, and severe LBP)
differed in their trunk velocity test scores, multivariate analysis of variance (MANOVA)
was conducted and the Bonferroni post-hoc tests were used to identify where significant
differences occurred.
To determine the relationship between disability and the trunk velociiy test,
Pearson product-moment correlation coefficients were calculated to drtcrminc the
association between scores on the disability questionnaire and the kinematic variables i'or
the thoracic, thoracolumbar, lumbar segments and sacrum. The benchmarks i b r
interpretation of the Pearson correlation coefficients were 0.00 to 0.25 = little or no
relationship; 0.26 to 0.50 = fair degree of relationship; 0.51 to 0.75 = moderate; and >
0.75 = good to excellent relationship (Portney & Walkins, 1993). All kinematic variables
were entered into a stepwise multiple regression analysis to determine their con~ribution
ro the variance in the disability scores.
All analyses were conducted with the SPSS statistical package and a siyn~tic:cncc
level of p < 0.05 was adopted.
Results
A total of 74 male volunteers participated in this study. No significant diflcrcnccs
for age, height, and weight were observed among the three groups (p ; 0.05).
Demographic information for the healthy and LBP groups are shown in Table 4.1.
For symptomatic subjects, the moderate LBP group (MLBP) presented a mean
disability score of 22% (f 8%) and the severe LBP group (SLBP) presented a mean of
46% (+ 6%). All asymptomatic subjects had a zero disability score.
Working characteristics differed between the two groups of' LBP. Thc scvcrc
group had a lower work capability than the moderate group. Twenty five percent of the
SLBP were on sick leave. 35% were working in modified duties, and only 40% were in
their normal working activities. In the moderate group no subject was on sick leave, only
20°/0 of the subjects were working in modified duties, and the majority of the subjec~s
(80%) were working normally.
All healthy subjects reported no back pain before and after the trunk velocity t t x .
h o n g the MLBP group, 5 subjects reported minimal pain ( 1 to 3 on thc pain scalc) and
the remaining 17 reported no pain before the test. Two SLBP subjects reported rnoderatc
pain (4 to 5 on the pain scale), 10 subjects reported minimal pain ( I to 3 on the pain
scale) and the other 12 subjects reported no pain before the test. No changes in the pain
level were reported in either group after the test.
Table 1.1 - Demographic information for the healthy and LBP groups
Groups Height Weight
(meters) (kg-)
Mean Range Mean Range Mean Range
Healthy 35 21 - 58 1.77 1.65-1.90 86.7 67 - 11s (n = 30)
Moderate 33 20 - 59 1.78 1.65 - 1.89 7 8 . 2 59 - 110 LBP
(n = 22)
Severe LBP 38 2 4 - 6 0 1.80 1.65 - 1.90 53.0 58 - 120
For the peak values on the trunk velocity test. the nican values For the nlasinlum
ROM flexion, velocity and acceleration were lower for the thoracic. thoracolumbar. ;lnd
lumbar segments and sacrum in the SLBP group when compared to the hcal~hy and
MLBP groups. The MLBP group also yielded lower values when compared to thc hcdrll\
group. The findings are summarized in Table 1.2.
Multivariate analysis of variance (MANOVA) showed that the kinematic
variables for the thoracic, thoracolurnbar, lumbar segments and sacral mglc wcrc
significantly different at 0.05 level. According to the Bonferroni post-hoc rests, t h ~
kinematic variables from the trunk velocity test were different between the SLBP group
and the healthy group and between the two LBP groups (Table 4.3). The thoracic peak
velocity and thoracic peak acceleration were the only variables where the healthy g o u p
differed from the MLBP group. All the other variables showcd no diffcrcncc b e t ~ c c ~ ~
these two groups.
The correlations between the disability scores and the spinal kinematic variables
varied from little to moderate. Moderate correlations ( r = -0.209 to r = -0.553) wcrc
obscrved for the thoracic peak velocity and thoracic acceleration variables. The
maximum ROM flexion for the thoracolumbar segment and sacral angle showed little
correlation with the disability score, and all the other variablcs yielded only a h i r
relationship with the disability score. These findings are summarized in Tablc 4.4.
The stepwise multiple regression analysis was performed includmg a1 1 thc
kinematic variables. The results showed that 52% of the variance oS the obst.mcd
disability score could be explained by the peak thoracic velocity, peak thoracolun~bar
acceleration, and peak lumbar velocity (Appendix 7).
Table 4.2 - Descriptive data for spinal kinematic variables
Variables Healthy MLBP SLBP Mean + SD Mean + SD Mcm ? SI)
--_L_._
Thoracic Segnr eft t
Mmimum ROM Flexion 31 + 13 30 t14 16 -t 8
Peak Vciocity 74 k 30 50 + 23 32 2 13
Peak Acceleration 693 + 227 506 k 215 311 + 165
Thoracolurnbar Segment
Maximum ROM Flexion
Peak Velocity
Peak Acceleration
Lumbar Segment
Maximum ROM Flexion
Peak Velocity
Peak Acceleration
Sacral Angle
Maximum ROM Flexion 63 4 12 60 k 16 49 + 13
Peak Velocity 197 + 42 165 k 60 126 + 57
Peak Acceleration 1189 + 470 998+271 7 2 7 t 2 5 9
Table 4.3 - Bonfcrroni test
- -
Variables Healthy x MLBP Healthy x SLBP MLBP x SLBP p-value p-value p-valut: --
Thoracic Segment
Maximu~n ROM Flexion
Peak Velocity
Peak Acceleration
Thorucolumbar Segment
Maximum ROM Flexion
Peak Velocity
Peak Acceleration
Lumbar Segmerrt
Maximum ROM Flexion
Peak Velocity
Peak Acceleration
Sacral Angle
Maximum ROM Flexion
Peak Velocity
Peak Acceleration --
* Significantly at 0.05 level * * Significantly at 0.0 1 level
Table 4.4 - Pearson Correlation Coefficients (r) between disability score and spinal kinematic variables
Variables Pearson correlation (r) p-value
Thoracic Segment
Maximum ROM Flexion - 0.382
Peak Velocity - 0,553
Peak Acceleration - 0.547
Thoracolumbar Segment
Maximum ROM Flexion
Pcak Velocity
Peak Acceleration
Lumbar Segrnent
Maximum ROM Flexion
Peak Velocity
Pcak Acceleration
Sacral Angle
Maximum ROM Flexion - 0.214
Peak Velocity - 0.282
Peak Acceleration - 0.360
pp - -
* Significant at 0.05 level * * Significant at 0.01 level
Discussion
In this study, the pain behavior of the subjects before and after thc test did not
change, suggesting that the test is safe with little risk of causing or increasing pain. Mas1
of the subjects in the study were pain free. or with minimal complaint. Only t ~ o suhjc.cts
reported moderate pain before the test, which did not change after completing the tcst.
l hese tacts suggested that pain was no1 a limiting hctor during the trunk \,clocirv icst.
Ahem et al. (1990) reported that pain was a significant predictor for impairn~cnt.
suggesting that pain may interfere with the clinical assessment outcomes of chronic LBP
patients. Hupli et al. (1996) measured the isokinetic performance capacity in subjects
with severe LBP and found that the results were influenced by the increase of pain during
the test. Mcintyre et al. (1991) reported that the normal group and the LBP group could
be identified by the different preference of motion, with the LBP group moving at u
slower velocity than the normal group. Although their study does not report any subject
complaint of pain, Mcintyre et al. concluded that the restriction of motion could be
attributed to pain induced during motion or mechanical factors.
Escola et a\. (1996) used a dynamic spinal ROM test to quantify LBP. In their
study, the Oswestry Disability Questionnaire was also used to determine rhe level of
disability of the LBP group. The mean Oswestry score of 2J0/0 was reported for their LBP
group, which matches the Oswestry score of the MLBP group in this study (22% + 8%).
In addition, they reported no signif cant differences between the healthy and LBP .- croup
for the dynamic ROM and velocity in the lumbar segment and in the sacrum, which
agrees with the findings in the present study. McClure et al. (1997) also reported similar
results. Simmonds et al. (1998) found that dynamic ROM and velocity for the lumbar
segment were different between healthy and severe LBP. Although they used the Roland
and Moms Disability Questionnaire to determine the severity of the LBP group. their
results agree with the results reported in this study.
The thoracolumbar ROM. velocity, and acceleration were di fferent between the
healthy and severe groups. The trunk velocity test was used by Marras ct a]. (1995) to
discriminate between healthy and LBP subjects. Their results partially agree with the
present study. They found that the thoracolumbar velocity and acceleration variables
were more sensitive to discriminate between the two groups. but the ROM was not Sound
to be a good discriminator. The difference in the ROM results was likely due lo the
application of different test protocols. Marras et al. (1995) used the restricted test
protocol which limited the ROM when compared with the free test protocol that was used
in this study. Another possible explanation for the difference in the results might be duc
to the different methods of classifying the LBP group. Marras et al. (1995) recruited only
subjects with well-diagnosed low back disorders, whereas in this study a disabiliiy
questionnaire score was used to categorize the symptomatic individuals. Another study.
which did not use disability as criteria to determine the LBP group, found also that
dynamic thoracolumbar R.OM and velocity were sensitive to distinguish between healthy
and LBP groups (Bishop et al.. 1997).
In this study, among all the segments of the spine, the most sensitive kinematic
variables to differentiate between healthy and SLBP groups were the thoracic velocity
and thoracic acceleration variables. These vanables were able to differentiate the health),
group from the MLBP and SLBP groups and between the MLBP and SLBP groups.
These findings suggested that the thoracic segment may have a significant impact on the
process of quantifying LBP, especially for its sensitivity in differentiating between two
subgroups of LBP individuals.
The thoracic velocity and acceleration variables also had the strongest correlation
with the disability scores when compared with other variables. Although many
researchers reported poor correlation between physical test such as ROM and le\*cl 01'
disability (Mellin, 1987; Triano & Schultz, 1987; Hazard et al., 1991 ). the thoracic
velocity (r = 0.55) and acceleration (r = 0.54) in the present study showed modcratc
relationship with LBP disability. Waddell et al. (1992) and Simmonds et al. (1909)
reported a fair correlation between lumbar ROM, lumbar velocity, sacral ROM and LBP
disability. These findings are similar io the results for the kinematic variables used i n ~ h c
present study.
The peak thoracic velocity, peak thoracolumbar acceleration, and the peak lumbar
velocity explained 52% of the variance in the disability scores. Further research, which
involves c w e registration, normalization and curve shape analyses, may strengthen this
relationship in a similar manner as reported by Marras et al. (1995). The current mulyscs
suggested that the kinematics of thoracic segment is a potential source of information
related to LBP and confirms the importance of the velocity and acceleration kinematic
variables.
Conclusion
This study showed that the kinematic variables for the thoracic, thoracolumbar,
and lumbar segments, and sacrum measured during the trunk velocity test were
significantly different between the severe low back pain group and the healthy group and
also between the severe low back pain eroup and the moderate lnw h a r k pair! grcup. T!Y
thoracic peak velocity and peak acceleration variables were the most sensitive to identify
kinematic differences in the LBP group, because they not only were able to detect
differences between healthy and LBP subject, but also they were able to find kinematic
differences between two subgroups of LBP.
The thoracic peak velocity and peak acceleration variables yielded the strongest
correlation with the disability score. The thoracic peak velocity was the main variable in
explaining the variation in the disability score. followed by the thoracolumbar
acceleration and then lumbar velocity. This study confirmed the importance of thc
velocity and acceleration variables in the study of the spinal motion and showed tha~ thc
thoracic segment might provide more information about low back pain sufferers' spinal
motion profile than any other segment of the spine.
References
I . Ahern DK, Hannon DJ, Goreczny AJ, Follick MJ, Parziale JR: Correlation of chronic low back pain behavior and muscle function examination of the fleniorl- relaxation response. Spine l5:92-95, 1990.
2 . American Medical Association: Guides to evaluation of permanent impairment. In American Medical Association. Chicago, 1990.
3. Andersson GBJ: Epidemiologic aspects on low back pain in industry. Spi~re 6 5 3 - 60, 1981.
4. Bergquist-Ullman M, Larsson U: Acute low back pain in industry: A controlled prospective study with special reference to therapy and confounding factors. Acta Ortlropaedica Scandinavica Supplementurn No. 170: 1977.
5. Biering-Sorensen F: Physical measurements of risk indicators for low hack trouhlc over a one-year period. Spine 9: 106- 1 19, 1984.
6. Bishop IB, Szpalski M. Ananthrarnan SK, Mclntyre DR. Pope MH: Classification of low back pain From dynamic motion characteristics using an artificial neurul network. Spine 22:299 1 -2998, 1997.
7. Bohannon RW: Cinematographic analysis of the passive straight-leg-raising test for hamstring muscle length. Physical Therapy 62: 1269- 1274. 1982.
8. Deyo RA: Measuring the functional status of patients with low back pain. :lrchiw.s of Physical Medicine Rehahilitation 69: 1044- 1053. 1988.
9. Erdil M, Dickerson OB, Glackin E: Diagnosis and medical management of work related low back pain. In Cumulative Trauma Disorders: Preve)rlior~, evaluation, and treatment. eds. Erdil, M & Dickerson, 0B.San Francisco, Van Nostrand Reinhold, 1996, pp. 44 1 -498.
10. Esola MA, McClure PW, Fitzgerald GK, Siegler S: Analysis of lumbar spine and hip motion during forward bending in subjects with and without a history of low back pain. Spine 2 1 :7 1-78, 1996.
1 1. Evans JH, Kagan A: development of functional rating scale to measure treatment outcome of chronic spinal patients. Spine 1 1 :277-28 1, 1986.
12. Fairbank JC, Davks JB. Couper J. O'Brien J.P.: The Oswrstry low back pain disability questionnaire. Physiotherapy 66:U 1-273, 1980.
13. Fordyce WE, Lansky D, Calshyn DA, Shelton JL, Stolov WC. Rock DL: Pain measurement and pain behavior. Pain 18:53-69, 1984.
1 Frymoyer JW, Pope MH, Costanza MC: Epidemiologic studies of low back pain. Spi~re 5:4 19-423, 1980.
15. Hazard RG, Bendix A. Fenwick JW: Disability exaggeration as a predictor of hnctional restoration outcomes tbr patients with chronic low back pain. Spiuc 16:1062-1067, 1991.
16. Hupli M, Hurri H, Luoto S, Sainio P, Alaranta H: Isokinetic performance capacity of trunk muscles. Part I: The effect of repetition on measurement of isokinetic performance capacity of trunk muscles among healthy controls and two different groups of low back pain patients. Scandinavian Jounrul 01' Rehabilitation Medicine 28:201-206, 1996.
17. Ito T, Shirado 0. Suzuki H, Takahashi M, Karneda K. Strax TE: Lumbar trunk muscle endurance testing: An inexpensive alternative to a machine for evaluation. Archives of Physical Medicitle Rehabilirurion 7 7 : 75 -79, 1 9%.
18. Klein AB, Snyder-Mackler L, Roy SH, DeLuca CJ: Comparison of spinal mobility and isometric trunk extensor forces with electromyographic spectral analysis in identifying low back pain. Physical Therapy 7 1 :445-454, 1 99 1 .
19. Mamas WS, Wongsam PE: Flexibility and velocity of the normal and impaired lumbar spine. Archives ofPhvsica1 Medicine Rehabilitation 6 7 2 13-2 17, 1986.
20. Marras WS, Pamianpour M, Ferguson SA, Kim JY, Crowell RR, Bose S. Simon SR: The classification of anatomic- and symptom-based low back disorders using motion measure models. Spine. 2O:253 1-2546, 1 995.
21. Masset D, Malchaire J, Lemoine M: Static and dynamic characteristics of the trunk and history of low back pain. International Journal of Industr~al Ergonomics 1 1 :279-290, 1993.
22. Mayer TG, Kondraske G, Beals SB, Gatchel W: Spinal range of motion. Accuracy and sources of error with inclinometric measurement. Spine 22: 1976- 1984, 1997.
23. McClure PW, Esola M, Schreier R, Siegler S: Kinematic analysis of lumbar and hip motion while nsing from a forward, flexed position in patients with and without a history of low back pain. Spine 22552-558. 1997.
24. McGregor AH, McCarthy ID, Hughes SP: Motion characteristics of the lumbar spine in the normal population. Spine 2O:242 1-2428, 1995.
25. McGregor AH, Dorc CJ, McCarth ID, Hughes SP: Are subjective clinical findings and objective clinical test related to the motion characteristics of low back pain subjects? Journal of Orthopaedic & Sports Physica! Therupy 28 :370-3 77, !998.
26. McIntyre DR, Glover LH, Conino MC, Seeds RH, Levene JA: A comparison ol'thc characteristics of preferred low back motion of normal subjects and low back pain patients. Jotrnzol of Spinal Disorders 4:90-95, 199 1.
27. Mellin G: Correlation of spinal mobility with degree of chronic low back pain alicr correction for age and anthropometric factors. S p i w 1 2464-468, 1987.
28. Mellin G: Correlations of hip mobility with degree of back pain and lumbar spinal mobility in chronic low back pain patients. Spirir 1 3:668-670, 1 988.
29. Nachemson AL, Bigos SJ: The low back. In Addt Orthopoedics. eds. Cruess, RL & Rennie, WRJ.New York, Churchill Livingstone, 1984, pp. 843-87 1 .
30. Porter JL, Wilkinson A: Lumbar-hip flexion motion: A comparative study between asymptomatic and chronic low back pain in 18- to 36-year-old men. Splw 22: 1508- 15 14, 1997.
3 1 . Roland M, Moms R: A study of the natural history of the low back pain. Part I!: Development of guidelines for trials of treatment in primary care. Spine 5: 145- 150, 1983.
32. Simmonds MJ, Olson SL, Jones S, Hussein T, Lee E, Novy D, Radwan H: Psychometric characteristics and clinical usefulness of physical perfomance test in patients with low back pain. Spine 23:2412-2421, 1998.
33. Spitzer WO: Scientific approch to the assessment and management of activity- related spinal disorders. A monograph for clinicians. Report of the Quebec Task force on Spinal Disorders. Spine 12:s 1-S59, 1987.
34. Spratt KF, Lehman TR, Weinstein JW: A new apprach to low back examination: Behavioral assessment of mechanical signs. Spine 15 :96- 102, 1990.
35. Stratford PW, Binkely JM: Measurement properties of the RM- 18: X modified version of the Roland - Morris Disability Scale. Spi)le 7 2 : N 16-24? 1. 1997.
36. Stratford PW, Binkley JM, Riddle DL Guyatt GH: Sensitivity to change of the Roland-Moms Back Pain Questionnaire: part 1 . Plzysicul Tl~erupv ?8: 1 186- 1196. 1998.
37. Thomas E, Silman AJ, Papageorgiou AC, Macfarlane GJ, CroA PR: Association between measures of spinal mobility and low back pain. An analysis of new attenders in primary care. Spine 23:343-347, 1998.
38. Triano JJ, Schultz AB: Correlation of objective measure of trunk motion and muscle function with low-back disability ratings. Spine 1 M 6 1-565. 1987.
39. Waddell G, Somerville D, Henderson L, Newton M: Objective clinical evaluation of physical impairment in clinical low back pain. Spine 1 7:6 17-628. 1992.
40. Wolf SL, Basrnajian JV, Russe TC, Kurtner M: Normative data on low back mobility and activity levels. American Journal of Physical Medicine 5 8 2 17- 229, 1979.
Chapter 5
Queen's-Dupont Study: The Use of the Trunk Velocity Test
in a Longitudinal Study
Introduction
Low back pain (LBP) has been responsible for the high rate of disability amon%
workers and also the high costs in industry (Abenhilim & Suissa, 1987; Frank et al, 1006;
Hagen & Thune, 1998). The multifactorial etiology of low back pain has been cited as
one of the main reasons for the difficulty in designing a single test to identify porsntial
back pain sufferers (Dales et al.. 1986; Burton et al., 1989). Many studies have attempted
to identify individuals with low back problems or predict those who have the potential to
develop LBP based on psycho-social and physical measurements (Beiring-Sorensm.
1984; Bigos et al., 1986; Burton et al., 1989; Bigos et al., I99 1).
In 1984, Beiring-Sorensen performed a one-year follow up of 412 nlcn and 479
women, to investigate whether physical measurements could be prognostic indicators for
LBP. They found that back muscle strength and endurance, back ROM and hamstrings
flexibility were good indicator of LBP, but anthropornctric measurements were of no
prognostic value. Troup et al. (1987) also used a battery of physical tests in the attempt o r
predicting LBP in more than 3000 subjects. The battery of test included anthropometric
measurements, back flexibility, back ROM, maximal lifting strength and aerobic
condition. Their results showed that physical factors have little prediction capacity for
LBP. This poor predictive capacity for the physical tests was also observed in studies
performed by Burton et al. (1989) and Battie et al. (1990). Three thousand and twentv
employees from the Boeing Company were involved in ;l longitudinal study whose
objective was to determine which psychosocial and physical measurements would predict
low back pain. Their results showed that nonphysical factors were better predictor of low
back pain than were physical measures. The strongest physical measure relate to LBP
was the straight leg raising test, while the other measurements, such as ROM and lifting
strength, were not helpful in predicting LBP (Bigos et al., 1992). The majority of the
studies above reported that the spinal ROM was not a good predictor of LBP. but in all of
these studies only the static spinal ROM was used. None of them used dynamic spinal
variables, such as velocity and acceleration, as outcomes.
Marras & Wongsam (1986) studied the lumbar spinal dynamic during t kx ion and
extension motion in healthy normal and LBP subjects. They found that the thoracolumbar
peak velocity was more sensitive in differentiating between healthy and LBP subjects.
This finding was later confirmed by other studies, which also introduced another variable,
acceleration, as a indicator of LBP (McIntyre et al., 199 1 ; Masset et ai., 1993; Marras et
al., 1995; Chapter 4). Masset rt al. (1993) and McIntyre et al. (1991) studied the dynamic
motion of the lumbar region while Marras et al. (1995) concentrated on the
thoracolumbar region from approximately T7 to S 1. In the Chapter 4 a more exploratory
study was performed analyzing the kinematic variables from the thoracic, thoracolumbar,
lumbar and sacrum regions of the spine during saggital flexion and extension motions.
This study showed that dynamic ROM, velocity and acceleration variables from the all
four regions of the spine were good indicators of LBP when healthy and severe low back
pain subjects were compared. However, when healthy and MLBP subjccts wcrc
compared. only the thoracic velocity and acceleration peak values were different. 7'hc
studies above suggested that spinal motion test with continuous dynamic protilcs of
motion with higher order derivatives should be investigated as study a physical test
measurement used in a longitudinal of LBP.
The purpose of this study was to determine whether the thoracic, thoracolumbar.
lumbar and sacral kinematic variables were able to differentiate subjects who would
develop low back pain in a longitudinal study.
Methods
The present study was part of a longitudinal research project that rneusurcd
various physical, lifting and health and lifestyle parameters in attempt to predict which
subjects would get low back pain (Weber et al., 1999). The longitudinal study was carried
out at the Dupont Company located in Kingston. Canada. Those who participated in the
trunk velocity test were selected according to the following criteria: males; no previous
experience of LBP or no LBP within the last two years and never sought for medical
treatment and changed activities. The subjects selected were tested from October to
December 1994. Before the test started, each subject received a written and verbal
explanation of the purposes and the protocol of the study and signed a consent form
(Appendix 8). Follow-ups on the occurrence of LBP disability using the Oswestry Low
Back Pain Disability Questionnaire were conducted from January 1 995 to January 199 7.
Trunk Velocity Test
The Polhemus ~ a s t r a k ~ ~ was used to collect kinematic data of the spine durins
the tmnk velocity test. This device is an electro-magnetic tracking system for the
measurement of the position and orientation of four sensors in space. Infom~ation about
the system and subject preparation were provided in the Chapter 2. The only differcncc in
the subject set up was that in the present study only three sensors were used to map the
thoracic and lumbar segments, and sacrum (Figure 5. I ) .
The trunk velocity test was performed using the Free test protocol as reported in
Chapter 3. All the subjects were pain free at the time of the test. Maximum ROM flexion.
peak velocity and peak acceleration values for the thoracic and lumbar segments. and
sacrum were measured. Two trails with five repetitions each were collected for every
subject, but only the second trail was considered in the analysis. The first trial was
considered a warm-up.
Disability questionnaire
The Oswestry Low Back Pain Disability Questionnaire (Fairbank et al.. 1980)
was used to assess the subjects' level of disability. More information about the Oswestry
questionnaire was given in Chapter 3. This questionnaire was administrated 4 times over
the two-year period (June 1995, December 1995, June 1996, December 1996). Only the
subjects who had experienced LBP during the current survey period were asked 10
complete the Oswestry questionnaire.
'igure 5.1 - Fastrak set up sensors at thoracic vertebrae 1 (T 1 ). lumbar vertebrae 2 (L 1 ) and sacral region
Data analysis
The data collection was performed in a designated room at Dupont Canada Inc.
(Kingston site). Since the ~ a s t r a k . ' ~ signal can be distorted by the presence of rnctallic
conductors located nearby or between the source and the sensors. calibration of the data
was required to account for distortion in the magnetic field observed in the area. The
calibration was performed using a calibration grid developed by Day et al. (1988) and
calibration software by Murdoch (1996). The calibration grid and collection area before
and after correction is illustrated in Figure 5.2.
The data were collected using customized software at 28 Hz on a 386 personal
computer. Residual analysis was performed on the data to determine the appropriate tiltcr
rate and a double pass Butterworth filter of 3 Hz was used to filter the velocity and
acceleration data aAer differentiation.
During the Follow-up period all healthy subjects were asked if they had
experienced LBP. Those who answered "yes" and had their first occurrence of pain
during the follow-up period formed the low back pain group.
The Oswestry Disability Questionnaire was analyzed in accordance with
guidelines suggested by the authors (Fairbank et al., 1980). Subjects with a score from
0% to 20% were considered to have minimal disability, 20% to 40% moderate disability.
40% to 60% severe disability, 60% to 80% crippled, and 80% to 100% bed-bound or
exaggerated.
The original sample From Dupont had two subgroups selected: those with no back
pain (NLBP) and those who did not have low back pain for over two years and did not
seek for medical help or changed their activities. To see if these subgroups could be
Figure 5.2 - Calibration test area: (A) calibration frame, (B) observed space. and (C) corrected space
collapsed into one group. an independent student t-statistic was performed on the
kinematic variables.
Independent sample student t-statistic was conducted to compare the means oi' ltlc
spinal kinematic variables between the group that developed LBP and the group thac did
not developed low back pain (No LBP). The statistical analyses were conducted with the
SPSS statistical package and a significance level of p < 0.05 was adopted.
Results
A total of 91 volunteer employees fiom the Dupont Canada Inc. (Kingston site)
participated in this study. No significant difference was observed in thc kinematic
variables of the two initial groups, and so they were treated as one group. During thc iwo-
year follow up, 17 of them developed LBP and the remaining 74 did not. No significant
difference was observed between the group of subjects who developed LBP and those
who did not when age, height and weight were compared (Table 5.1).
Nine subjects (53%) developed low back pain during the first six month o f the
study, 5 subjects (29% developed LBP after one year, 2 subjects (12%) alter one year
and six months and only one (6%) developed LBP after two years (Figure 5.3). The mean
disability score for the LBP group was 18%. The great majority of the group ( 1 3 subjects)
were classified as having a minimal level of disability, 2 subjects were considered
moderately disabled, and the other 2 subjects were considered severely disabled (Figure
5.4).
The descriptive data from the spinal kinematic variables showed that most of the
motion in both groups during the trunk velocity test occurred at thc sacral region
followed by the lumbar and the thoracic segments. The independent sample student r -
statistic showed that the thoracic peak velocity was the only vanable capahlc 01'
differentiating the LBP group from the no LRP group. The other thoracic i-ariablcs uvc.rc.
not significantly different between the two groups. Also. no statistically si~nil icant
results were observed between the two groups for the maximum ROM flexion. pcak
velocity, and peak acceleration in the lumbar segment and sacral angle. These tindings
are summarized in Table 5.2.
Discussion
The spinal ROM has been used in several longitudinal studies with the purposi. ol'
predicting LBP. However, the results have been more discouraging than optimistic
(Being-Sorensen, 1984; Troup et al., 1987; Burton et al., 1989; Battie et a!., 1990).
However, the ROM tests applied in these studies were considered static measures. once
only the endpoint of the motion was measured. The present study measured dynamic
spinal kinematic variables attempting to identify differences in those variables beforc
individuals developed LBP.
The initial goup of 91 employees from Dupont showed kinematic measures
(dynamic ROM, velocity and acceleration variables for the lumbar segment) simi lar to
those reported by other researchers that have studied healthy subjects (Table 5.3) . The
only disagreement, probably due to protocol, was the lower velocity data reported by
Tahle 5.1 - Demographic information for the No LBP and LBP groups
Croups Weight (kg-)
Mean SD Mean SD Mean SD
No LBP 33 9 1.77 7 85.6 13 (n = 74)
LBP (n= 17)
Figure 5.3 -Sequence of low back pain occurrence in the two year follow up
. . - - - -
Moderate 1 2O/o
Figure 5.4 - Level of disability among LBP subjects
Table 5.2 - Descriptive data for the spinal kinematic variables and the p-value for the independent sample T- test
Variables NO LBP LBP p-value Mean + SD Mean + SD
n = 74 n = 17 Thoracic Segment
Maximum ROM Flexion 29 + 12 24 210 0.1 16
Peak Velocity 87 +_ 37 65 +_ 23 0.014*
Peak Acceleration 550k 241 474 + 235 0.094
Ltrmbar Segment
Maximum ROM Flexion
Peak Velocity
Peak Acceleration
Sacral Angle
Maximum ROM Flexion 63 + 16 67 + 15 0.299
Peak Velocity 175 -t. 41 181 k 4 6 0.558
Peak Acceleration 1297 k 367 131 1 + 441 0.182
* Significant different at 0.05 level
Escola et al. ( 19%). They used a protocol where the subjects were asked to mo\.c in
comfortable manner throughout their flexion ROM, whereas the subjects in the other
studies were asked to perform the test as fast as possible. The thoracic segment and sacral
angle spinal kinematic variables were in concurrence with the findings rep0ric.d 111
Chapter 4 (Table 5.3).
The findings of the present study showed that it was possible to idrntifv
differences between subjects that will develop LBP and others who will not. The thoracic
peak velocity was the only kinematic variable that was significantly differently between
the two groups. In order to compare the thoracic kinematic variables between the present
study and the Chapter 4, the Dupont data were divided in three groups, that is. hcalthy.
moderately disabled and severely disabled as suggested by Fairbank ct al. (1980) and
adopted in Chapter 4 (Table 5.4).
I t is important to note that the thoracic variables in the present study werc
collected when all subjects were initially asymptomatic and in Chapter 4 two distinct
groups were analyzed, that is. one asymptomatic and the other with low back pain
complaints. The two subjects from the Dupont study that scored severe disability on the
Oswestry questionnaire had similar kinematic measures as in Chapter 4. These two
subjects also reported their first episode of pain six-months after the data were collected.
suggesting that, although they were asymptomatic during the time of the data coilectlon,
their thoracic kinematic motions were already severely impaired.
The thoracic kinematic variables for the healthy and moderately disabled goups
were also similar to the healthy and MLBP groups in the Chapter 4 study. On this data
the thoracic peak velocity showed a significant difference between the healthy and the
Table 5.3 - Comparison among studies of the thoracic, lumbar. and sacral kincma~ic. variables
ROM Velocitv Acceleration Studies Mean (SD) Mean (sd) Mean (SD)
Deprec Degrcc!s ~ c ~ r c c i s : --
Lumbar Segment
Present study 49 (1 4) 129 (37) 780 (247)
Marras & Wongsarn (1986) 43 120
Escola et al. (1 996) 40 (14) 42 (12)
Chapter 4 SO (16) 13 1 (40) 843 (272)
Tho rack S e w err t
Present study 28 (12) 83 (36) 537 (241)
Chapter 4 31 (13) 74 (30) 693 (227)
Sacral Angle
Present study 64 (16) 178 (42) 1299 (378)
Chapter 4 63 (12) 197 (42) 1 189 (470)
' l 'able 5.4 - Cornpanson between Dupont and Chapter 4 study in terms of thoraclc kinematic variables and level of disability
Level of Disability ROM velocity Acceleration Oswestry Mean (SD) Mean (SD) Mean (SD) Mean (SD)
Degree Degrcds ~cgrcds' O / a
Healthy
Present study (N = 74) 28 (12) 83 (36) 537 (241) 0
Chapter 4 ( N = 30) 31 (13) 74 (30) 693 (227) 0
:Moderare
Present study (N = I 5) 25 (10) 58 (22) 499 (235) 13 (8)
Chapter 4 (N = 22) 31 (12) 50(22) 506 (2 1 5) 22 (8)
Severe
Present study (N = 2) 17 (1) 35 ( 9 ) 2 5 5 (30) 57 ( 7 )
Chapter 4 (N = 22) 16 (8) 35(11) 312(165) 46 ( 6 )
LBP groups, whereas in Chapter 4 the thoracic peak velocity and thc peak accrlcration
were the most sensitive to identify kinematic differences between those groups. This
difference might be explained by the fact that the Dupont's subjects were less Jisablcd
than in the Chapter 4 subjects.
Although in the present study the subjects were asymptomatic when rhc ~ r u n h
velocity test was performed, some of them already presented some restriction in their
thoracic peak velocity. A possible explanation for this fact is that these workers might be
in a pre-clinical phase where no pain has been observed but some kinematic changes haw
already start to occur before the symptoms can be observed. This fact was confirmed
when the thoracic peak velocity values were compared with the first onset of pain
reported by the subjects during the follow up (Figure 5.5). Subjects that developed LBP
in the first six mouths aRer the test had the lowest value for the thoracic peak velocity.
Those who developed LBP in the first year after the test had peak velocity lower than thc
subjects who developed LBP one year and a half and two years of following up.
Although this was a relatively small sample size, results would suggest that the trunk
velocity could be developed further to become a valuable prognostic test.
Conclusion
Results of this study showed that thoracic peak velocity was the only variable
sensitive enough to identify kinematic differences in the group that developed LBP in a
longitudinai study when the inclusion criteria limit subject to either no LBP or LBP in
last two years. Asymptomatic subjects who had lower peak velocities as measured during
Figure 5.5 - Thoracic peak velocity and the first occurrence of LBP
the trunk velocity test were the ones that developed low back pain during the two years
follow up. The creation of a database for the thoracic kinematic variables for healthy and
LBP subjects considering gender and age differences should be the ncxt step. thus
allowing the trunk velocity test be used more effectively. The database will allow thc 11s~
of this test in the process of LBP screening during periodical physical examinations m d
perhaps with further validation as an employee selection criteria. Individuals that prcscnl
lower values in the thoracic kinematic variable should be carefully examined for other
clinical signs of LBP and suggested to take part in a preventive program. since they might
be a potential candidate to develop LBP in the near future.
References
I . Abenhaim L, Suissa S: Importance and economic burden of occupational back pain: A study of 2,500 cases representative of Quebec. Journal of Occtcpulioncrl Medicine 29:670-674, 1987.
2. Battie, M. C., Bigos, S. J., Fisher. L. D., Spengler, D. hl., Hansson, T. H., Nachemson, A. L., and Wortle, M. D. The role of spinal flexibility in back pain complaints within industry: A prospective study. Spirle 16(8), 768-773. 1990.
3. Biering-Sorensen F: Physical measurements of risk indicators for low back trouble over a one-year period. Spine 9: 106- 1 19, 1984.
4. Bigos SJ, Spengler DM, Martin NA, Zeh J, Fisher LD, Nachemson AL. Wang MH: Back injuries in industry: A retrospective study 11. Injury factors. Spine 1 1 246- 251, 1986.
5. Bigos SJ, Battie MC, Spengler DM, Fisher LD, Fordyce WE, Hansson TH. Nachemson AL, Wortle MD: A prospective study of work perceptions md psychosocial factors affecting the report of back pain injury. Spine 16: 1-6. 1991.
6. Bigos SJ, Battie MC. Spengler DM, Fisher LD, Fordycr WE. Hansson TH, Nachemson AL, Zeh J: A longitudinal, prospective study of industrial back injury reporting. Clinics in &thopuedics and Related Research 2?9:22-3 3, 1992.
7. Burton AK, Tillotson KM, Troup JDG: Prediction of low back trouble frequency in working population. Spbie 14:939-945, 1989.
8. Dales JL, MacDonald EB, Porter RW: Back pain; the risk factors and its prediction in work people. Clinical Biomechanics 1 :2 16-22 1, 1986.
9. Day JS, Dumas GA. Murdoch DJ: Evaluation of a long-range transmitter for use with a magnetic tracking device in motion analysis. Joztrnul o/Biomeciiu~lm 3 1 :957-96 1, 1998.
10. Esola MA, McClure PW, Fitzgerald GK, Siegler S: Analysis of lumbar spine and hip motion during forward bending in subjects with and without a history of low back pain. Spine 21:71-78. 1996.
1 I . Fairbank JC, Davies JB, Couper J, O'Brien J.P.: The Oswestry low back pain disability questionnaire. Physiotlrerapy 66:Y 1-273, 1980.
12. Frank JW, Kerr SM, Brooker A, DeMaio SE, Maetzel A, Shannon H, Sullivan TJ. Norman RW, Wells R: Disability resulting from occupational low back pain. Part 1: what do we know about primary prevention? A review of the scientific evidence on prevention before disability begins. Spine 2 1 :2908-29 1 7, 19%.
13. Hagen KB, Thune 0: Work incapacity from low back pain in general population. Spine 232091-2095, 1998.
14. Marras WS, Pamianpour M, Ferguson SA, Kim JY, Crowell RR. Bose S, Simon SR: The classification of anatomic- and symptom-based low back disorders using motion measure models. Spine. 20:253 1-2546, 1995.
15. Masset D, Malchaire J, Lemoine M: Static and dynamic characteristics of the trunk and history of low back pain. hternational Journal of Indicstrial Ergo~ionlics 1 1 :279-290, 1993.
1 6. Murdoch DJ: Calibration of an oriented measurement system. Proceedmgs Js&h Annual Meeting of the Stalistical Society of Canada, 1996.
17. Troup, 1. D. G., Foreman, T. K., Baxter, C. E., and Brown, D. The perception of back pain and the role of psychophysical tests of lifting capacity. S p i m 12(7), 645-657. 1987.
18. Weber CL, Stevenson JM, Smith JT, Dumas GA, Albert WJ: A longitudinal study of development of low back pain in a industrial population. Suhmirred ro Sptrle, 1999.
Chapter 6
General Discussion and Conclusion
The aim of this thesis was to study the reliability and repeatability of the trunk
velocity test using the ~ a s t r a k ~ ~ and the applicability of this device in the asssssn~ent of-
the spinal kinematics of healthy and low back pain subjects during the trunk veloc~ty test.
Good within day repeatability was observed for the measurement of the trunk's
displacement, velocity and acceleration for all trunk segments. In addition, the ~astrak'''
yielded excellent reliability for the saggital plane motion and sood reliability for latcral
bending and rotation motions. All dynamic ROM flexion variables were lower in the first
trial of the test than in the second, however no difference was observed from trials two to
eight. This suggested that, during the first trial, some learning or adjusting process
occurred and it should be disregarded and considered only as warm-up.
The l?astrakTM and the Lumbar Motion Monitor provided comparable trunk
kinematics for subjects when performing the trunk velocity test using the same testing
protocol. Although the kinematic variables from the restricted test protocol (RTP) and
from the free test protocol (FTP) were correlated, they were significantly different. Lower
kinematic values, including dynamic ROM flexion, peak velocity, and peak acceleratlon,
were observed for the RTP than for FTP, suggesting that the RTP protocol restricts the
spine's range of motion. As such, the free test protocol should be used when performing
the trunk velocity test, since the spine's motion will not be restricted and therefore the
test results will not underestimate the spine's motion. As well, the FTP can be used by
devices other than the Lumbar Motion Monitor. In addition, the hstrakTM had the
advantage of providing kinematic values not only for the thoracolumbar segment, which
is measured by the LMM, but also for the thoracic and lumbar segments as well as
sacrum, which are not measured by the LMM.
The ~ a s t r a k ' ~ and the FTP were used to assess the spine's kinematics for healthy
and low back pain individuals while performing the trunk velocity test. The results
showed that the thoracic, thoracolumbar, lumbar and sacral kinematic variables wcrc
significantly different between the severe LBP group and the healthy and modcratc
groups. However, only the thoracic peak velocity and thoracic peak acceleration values
were different between the healthy and moderate LBP group, and between the moderate
and severe LBP subgroups. This suggested that these variables were the most sensitive to
changes in the spine's motion due to LBP. In addition, the trunk velocity test may also
have prognostic value. In a longitudinal study where asymptomatic subjects were
followed for a two year period, those who had lower thoracic peak velocities initially
developed low back pain within the two year period.
Low correlations were observed between the kinematic variables of different
spinal segments suggesting that each segment contributed differently during the dynamic
ROM flexion test. As such, each segment may provide different motion pattern
information that may be useful in the study of LBP individuals. The high level
derivatives for the thoracic segment may provide more information about the low back
pain subjects motion profile than any other segment of the spine.
Biomechanics of the spine during the trunk velocity test
The human spinal motion is complex because of the complex interaction among
its components (intervertebral discs, ligaments, articulation surfaces and muscles) to
produce effective movement. The motions of the whole spine are a summation of the
motions of the individual functional spinal units, which have their own physical and
biomechanical proprieties (Hamill& Knutzen, 1995).
The trunk velocity test required the subject to execute a symmetric dynamtc
flexion-extension spinal motion that was repeated five times as fast and as comfortably as
possible. During the flexion motion the transversus, rectus abdominus, and internal and
external oblique muscles are recruited to perform the motion. and during extension the
muscle action is attributed to the erector spinae (iliocostalis, longissirnus and spinalis)
and the paravertebral muscles (Intertransversarii, interspinales. rotatores, and multilidus)
(Benson, 1977). Ln an erected standing position a constant contraction of the postural
muscles is needed to maintain equilibrium. When the subject moves forward this
equilibrium is destroyed and the trunk, under the influence of gravity. tends to 611
forward. At this point, the antagonist muscles spring into action, contracting eccentrically
to slow the gravitational acceleration and to lower the trunk under control in the fonvard
direction (Rasch & Burke, 1971). To stop the motion forward and start the extension to
return to the standing position the extensors are required to contract.
The study of this spinal motion test showed that the dynamic ROM flexion.
velocity and acceleration values were lower for subjects with severe low back pain than
the healthy subjects. Although the study of the trunk motion patterns was not the
objective of this thesis, an examination of the curve shapes may help ssplam thc
differences observed between the healthy and the LBP groups.
Comparison between healthy and SLBP subjects
Figure 6.1 illustrates the motions of the dynamic ROM flexioniestension profiles
for the four spinal regions of the healthy and SLBP subjects. The curves of the healthy
subjects were smooth and homogeneous while the SLBP subjects showed more erratic
pattern. Another difference between the groups was the lower amplitude of the curves
observed in the SLBP than in the healthy subjects. Other authors also observed reduced
motion capability and less smooth motion profile for the lumbar (Hindle et al.. 1900) and
thoracolumbar (Marras et al., 1994) segments for LBP subjects when compared to
healthy individuals.
Long periods of pain might be one explanation for the differences found between
the groups. Pain can result in a reduction in the spine's ROM due to the shorten of soR
tissues and a decrease in the strength of the back musculature. In this situation. motion
limitations may result as a consequence of disuse, rather than a result of the initial injury
(Magnusson et al., 1998). Although most of the subjects were pain free during the test, i t
is possible that a protective mechanism was in place. According to Wolf et al. (197Y), a
learned guarding behavior can develop in response to pain, generating postural
abnormalities by compensatory neuromuscular patterns that develop over time and affects
trunk motion characteristics. These kinematics changes may happen not only when the
muscles are weak, but also when they are overloaded.
I - .---
Dyrumlc TH ROM Flrxlon - Healthy i Dynamic TH ROM Flexlon - SLEP I
Dyrunlc TL ROM Fkxlon Hulthy 140 ,- - - .-- -----.-. --
I Dynamic LU ROM Flrxlon HuRhy
I O y ~ m l c SA ROM Fk~locr - HsllUy
Dyrumlc TL ROM Fiaxlan SLBP
Dyrumk LU ROM Fkxlan . SLBP
Oynrmk SA ROM Fkxkn SLBP
Figure 6.1 : Patterns of motions for (A) thoracic (TH), (B) thoracolumbar (TL). (C) lumbar segments (LU) and (D) sacral angle (SA)
When the primary muscles of the back are weak or overloaded, smaller and less
developed muscles, such as multifidus, rotadores and intertransversarii. are recruited to
assist with the motion (Gracovetsky, 1990). According to Soderberg (1986), these smaller
and less developed posterior muscles are responsible for stabilization and fine movrrncnl
control of spinal motion segments and these functions can be affected negatively when
the posture muscles are recruited constantly to help the primary movers. This may
explain the erratic pattern of motion observed in the SLBP group, in which the
stabilization and fine movement control of the spine has been affected. This is also
mentioned by Marras et al. (1993) who reported that lower velocity and acceleration
values throughout the spine flexiodextension movement in LBP individuals could
indicate a biornechanical response to back musculature overload. The musculoskeletal
system response to the load can be the result of a single event such a high-impaci load
(fall) or adaptive change due to repeated stimulus from prolonged awkward back postures
(Porterfield & DeRosa, 1991).
Adaptive changes in the spinal musculoskeletal system can also affect the spinal
motion (Porterfield & DeRosa, 1991). Although it was not assessed, it is reasonable to
assume that the LBP subjects exhibited some of the structural adaptation, that happen
over the course of the years, either as part of the normal aging process of disc
dehydration or depending on their activity level and life-style. Shortened hamstring and
anterior hip muscles, tight joint capsules, weakened back or abdominal muscles are some
of the most observed changes that require adaptation of the spinal structures to perform
their normal hnction.
Comparison between healthy, MLBP and SLBP subjects
The thoracic kinematic variables were the most sensitive in identifying
differences between the healthy and the LBP groups. and between the two LBP
subgroups. In addition, the thoracic segment pattern of motion for the dynamic ROM
the only variable set that suggested the existence of curve differences among healthy
subjects (Figure 6.1 B). From the thoracic ROM it was possible to extract two subgroups
of healthy subjects, one presenting smoother and symmetric curves, and the otllcr
presenting more erratic traces with some similarity to the SLBP group. Group 1 consisted
of 18 subjects with greater than 20" range of motion and group 2 was made up of 12
subjects who had less than 20" range of motion in the thoracic spine (Figure 6.2).
When the thoracic dynamic ROM is compared between the healthy, MLBP, and
SLBP groups, it appeared that there was a transition of the pattem of motion from healthy
to SLBP (Figure 6.3). In the MLBP group, some subjects presented curves that resembled
the SLBP group and others presented curves more similar to the healthy group. Although
different patterns of motion were observed among the spine segments, the thoracic
section would appear to provide more motion information than the others do. One
hypothesis for these differences may be alternative coordination strategies adopted for
spinal segments during the trunk velocity test based on the health and mobility of the
spinal segments or degree of low back pain. According to Andersson & Winter ( 1 N O ) , a
person is able to use different spinal movement strategies to perform a task, and the
presence of any hnctional abnormality would require an individual to create a new
movement strategy to perform the task. As such, one possible explanation for the
decreased thoracic velocity and acceleration is that subjects with low back pain may
1
I I
1 Dynamic TH ROM Flexion - Group 1
Normalized Time I
Dynamic TH ROM Flexion - Group 2 -
Normalized Ttme
C I
Figure 6.2: Thoracic patterns of motion from healthy subjects
-- --- I
! Dynamic TH ROM Flexion - Healthy
I -40 - 1
, Normallzed Tlme
Dynamic TH ROM Flexion - MLBP
Normallzed Tlme
i I 1
Dynamic TH ROM Flexion SLBP 1 I I
Nomlizod T lme i
Figure 6.3: Comparison of thoracic pattern of motion among healthy, MLtJP, and SLBP subjects
esperience stiffness in their thoracic segment or may guard their motion bascd on a
learned behavior due to pain. This hypothesis could be investigated with the addition ol'
electromyography as an outcome measure. The motion dunng the trunk velocity tcst is
initiated in the pelvic area followed by the lumbar motion. then the thoracic. Since thc
thoracic segment is the free end of motion, it could be hypothesized that its velocity
would be directly associated to the rate of the flexion of'the lumbar and sacral region. I f
the subjects have their thoracic segment stiff or guard protected, then the coordination
pattern will be altered during the trunk velocity test resulting in slower thoracic velocity
and acceleration. To further investigate this hypothesis, analysis of curve shapes would
be needed.
Kinematic variables as predictors of LBP disability
Another interesting finding regarding the thoracic segment was that the thormc
peak velocity was the main variable needed to explain the variation of the disability
followed by the thoracolumbar acceleration and lumbar velocity. The combination of
these three variables accounted for 52% of variance on the Oswestry disability score. The
remaining 48% may be explained by other contributors to the developrncnt of
musclcskeletal disorder related to disability cited in the literature, such as illness
behaviors (Brena et al., 1979), psychosocial factors (Moon et a].. 1997), and
psychological aspects (Bongers et al.. 1993). Eventually a more complete model of
potential risk factors could be developed.
Summary
The present series of studies showed that the ~ a s t r a k ~ " and the trunk velocity test
to assess spinal kinematics is a promising device and test respectively to be used in the
clinical and industrial settings. These studies contributed in to a better understanding the
complexity involved in the spinal kinematic of healthy and LBP individuals. Differences
in the kinematic variables between the two groups were observed and the thoracic
segment provided the most sensitive kinematic infomation. Further invcstigat~on in the
pattern of motions created during the trunk velocity test will undoubtedly provide more
information than kinematic peak values from the thoracic, thoracolumbar, lumbar and
sacral (pelvic) segments.
General Conclusions
From the four studies carried out, the following conclusions were drawn:
The static and dynamic ROM measured by the ~ a s t r a k ~ ~ proved to be reliable and
repeatable.
8 Only two trials of the trunk velocity test are required to assess the spinal kinematics
variables. The first trial should be considered a warm-up with the second trial used
for analysis. There were no significant differences in peak values with additional
trials.
The use of different test protocols affected the results of the trunk velocity test. The
Free test protocol is preferred as it allowed the subject to perform the test using their
total spinal range of motion, and is suitable for use with other data acquisition
devices.
The ~ a s t r a k ' ~ provided comparable spinal kinematic information to the Lumbar
Mot ion Monitor.
The peak kinematic values for the thoracic, thoracolurnbar, and lumbar segments, and
sacral angle showed that the severe low back pain group differed from the healthy and
moderate low back pain groups.
The thoracic peak velocity and peak acceleration variables were different between
healthy and LBP subjects and between moderate and severe LBP suffers.
Fifty two percent of the variation on Owestry disability score was explained by tile
thoracic peak velocity, thoracolumbar acceleration and lumbar velocity vanablcs.
The thoracic peak velocity was the only variable sufficiently sensitive to difl'erentiaic
subjects who developed low back pain in a longitudinal study. Asymptomatic subjects
who yielded lower peak velocity values during the trunk velocity test initially were
the individuals that developed low back pain during the two year follow up.
Future Research
The findings reported in this thesis raised new issues relating to the spinal
kinematics and its impact on the assessment of LBP, which may be addressed in future
studies. Specific directions are:
To study the coordination among the segments of the spine between healthy and LBP
subjects while performing the trunk velocity test.
To study the electromyography activity in the paravertebral muscles at the thoracic.
lumbar and sacral regions of healthy and LBP subjects while performing the trunk
velocity test and compare these results to a standardized static test such as the Bering-
Sorensen test.
To create a database with kinematic information for the healthy population.
To study the kinematic variables and the pattern of motion in healthy and LBP
subjects with a large sample size considering age and gender difference. This study
would be directed to answer the following questions: Can spinal kinematic variables
and spinal pattern of motion be used:
to discriminate between LBP and asymptomatic subjects'?
to identify different clinical LBP diagnosis?
as outcome in the rehabilitation treatment?
as screening test for employee selection in the industry?
to predict LBP in a longitudinal study?
to prevent recurrence of LBP?
References
1. Andersson GBJ, Winters JM: Role of muscle in postural tasks: Spinal loading and postural stability. In Muifiple Muscle Systems: Bionlechunics and Movmlew Orgamkatiotl. eds. Winters, JM & Woo, S L Y .New Y ork, Springer-Verlag, 1990, pp. 377-395.
2. Benson DR: The back: Thoracic and lumbar spine. In Musculoskeletal Disorders. ed. DfAmbrosia, EUlPhiladelphia, J.B. Lippincott Company, 1977, pp. 145-260.
3. Bongers PM, Kornpier MA, Hildebrandt VH: Psychosocial factors at work and musculoskeletal disease. Scandinavian Journal of Work, Envirorime~fr & Heulrk l9:297-3 12, 1993.
4. Brena SF, Stegall PG, Chyatte SB: Chronic pain states: their relationship to impairment and disability. Archives of Physical Medicine d; Rehabilirarion 60:387-389, 1979.
5 . Gracovetsky S: Musculoskeletal function of the spine. In Multiple Muscle Systems Biomechanis and Movement Organization. eds. Winters, JM & Woo, SL- Y .New York, Springer-Veriag, 1990, pp. 4 10-437.
6. Hamill J, Knutzen KM: Functional anatomy of the trunk. In Bionlecliu~ricui SWS o/- Human Movement. eds. Hamill, J & Knutzen, KM.Philadelphia, Williams & Wilkins, 1995, pp. 284-324.
7. Hindle RJ, Pearcy MJ, Cross AT, Miller DHT: Three-dimensional kinematics of the human back. CZinical Biomechanics 5 :2 1 8-228, 1990.
8. Magnusson ML, Bishop JB, Hasselquist L, Spratt KF, Szpalski M, Pope MH: Range of motion and motion patterns in patients with low back pain before and after rehabilitation. Spine 23:263 1-2639, 1998.
9. Moon S, Brigham C, Sydnor M: Cumulative trauma disorders: Impairment and disability assessment. In Cumulative Trauma Disorders: Prevention, Evaluarion and Treatment. eds. Erdil, M & Dickerson, 0B.New York, Van Nostrand Reinhold, 1997, pp. 385-438.
10. Porterfield JA, DeRosa C: Principles of mechanical low back disorders. In Mechanical Low Back Pain: Perspectives in Functional Attaromy. eds. Porterfield, JA & DeRosa, C.Philadelphia, W .B.Saunders company, 199 1, pp. 1-18.
1 I . Rasch PJ, Burke RK: Movements of the spinal column. In Kbiesiology und itpplied Anatomy. eds. Rasch, PJ & Burke, RKPhiladelphia, Lea & Febiger, 197 1. pp. 269-299.
I ? . Soderberg GL: Trunk. In Kinesiology: Applicntion to Patilological Motiorl. e d . Soderberg, GL.Baltimore, Williams & Wilkins, 1986, pp. 267-307.
13. Wolf SL, Basmajian JV, Russe TC, Kurtner M: Normative data on low back mobility and activity levels. American Journal of Physical Medicine 5 8 2 1 7 - 229, 1979.
Consent Form I
Investigator: Mhrcio Marqal, PT, MSc. Ph.D. Candidate 545.2658 - School of Physical and Health Education 544.1300 - Home
Su~ervisors: Joan Stevenson, Ph.D. - School of Physical and Health Education - Queen's University - 545-6288
Pat Costigan, Ph.D. - School of Physical and Health Education - Queen's University - 545-6603
Title of the Study: " ~ a s t r a k ~ ~ Reliability and Repetability of Kinematics Variables from Spinal segments During Trunk Velocity Test"
Purpose of the study
This is a research project that aims to study the reliability and repetability of a magnetic tracking device ( ~ a s t r a k ~ ~ ) to assess trunk dynamic range of motion flexion (ROM), velocity, acceleration and static ROM.
Procedures Involved
Two day test will be required to complete all the measurements. You will spend approximately 1.5 hours to complete the measurements in the first day and 45 minutes on the second day. The test will take place at the biomechanic lab at The School of Physical and Health Education, Queen's University.
In the first day you will be asked to perfom a series of tests: 1 ) Physical measurements which include height, weight, etc. 2) Fastrak set up - Four sensors will be placed in your back and you be asked to perfom the following tests: a) Spinal Range of Motion Test - You will be encouraged to bent the spine as far as possible in the lateral (side to side), rotation (twisting) and flexion (forward). This test will be performed three times, b) Trunk Velocity Tcst - You will flex and extend the trunk in the sagittal plane as quickly as comfortably possible for 5 repetitions (one trial). Eight trials will be collected in the first day with two minute rest between trials. In the second day you will be asked to repeat the Range of Motion and four trials of the Trunk Velocity tests.
Risk and Benefits
There is minimal risk of injuries in all tests. The scientific data show that over 35 1 subjects have been involved in the Trunk Velocity Test with no reported of injuries. However, you may experience some discomfort in your back, but no pain should bc expected. If you feel back pain report it to investigator. Should discomfort occur, it should progressively resolve well within the 5 minute recovery period. There are no direct benefits to participating in this study, however i t is our hope that a new clinical instrumentation will be developed fiom this study for clinical assessment of low back pain problems.
Voluntary Participation
Participation in this study is on a voluntary basis and you are free to withdraw at any time for whatever reason. Withdrawal from the study will not affect your present or future medical care in any way.
Confidentiality
All information obtained is strictly confidential and your anonymity will be protected at all times. A numerical code will be assigned to your file and the number will be used on all data related to you. The consent form and data will be stored separately in locked files and be available only to the inwstigators. Thc informstion gathered may Sc used in scientific papers and presentations, but your name will not be used for either purpose. The records will not be used for any other purpose or disclosed to a n y third party without your permission.
The information included in this consent form has been explained to me by the investigator to my satisfaction. I have had the opportunity to ask questions or seek other opinions. I am aware that if I have any questions or concerns regarding the study I may contact the investigators at the numbers provided above at any time and I will keep a copy of this form for my own information.
I have read and understand the explanation of the procedures of this study. I have had the opportunity to ask questions, which have been answered to my satisfaction. I am voluntarily signing this consent form to participate in this study.
I have carefully explained to the subject the nature of the above research study.
Consent Form I1
Investieator: Mircio Marqal, PT, MSc. Ph.D. Candidate 545-2658 - School of Physical and Health Education 544- 1300 - Home
Supervisors: Joan Stevenson, Ph.D. - School of Physical and Heath Education - Q u c ~ n ' ~ University - 545-6288
Pat Costigan, Ph.D. - School of Physical and Heath Education - Queen's University - 545-6603
Title of the Study: "Trunk Velocity Test: Comparative Study Between ~astrak'." and I-umhar Mot im Monitor"
Purpose of the study
The purpose of this study is compare two trunk velocit test protocols using the Lumbar Motion Monitor (LMM), and compare the FastrakY\' and the LMM while performing the same trunk velocity test protocol.
Procedures Involved
You will spend approximately 1 hour to complete all the measurements, which will take place at the Biomechanics lab, School of Physical and Health Education, Queen's University.
You will also be asked to perform a series of tests: Physical measurements which include height, weight, etc; LMM restricted test protocol (RTP) - Using the LMM you will flex and extend the trunk in the sagittal plane as quickly as comfortably possible for 5 repetitions (one trial). Four trials will be collected with two minute rest between trials. During the test you will need to look and follow a target in a monitor sceen. LMM free test protocol (FTP) - The same test will be repeated ,but at this time no visual feedback will be provided. You will be allowed to move freely. Fastrak set up - Four sensors will be placed on your back and you will be asked to perform the same test above using the Free test protocol.
Benefits
There is minimal risk of injuries in all tests. Previous scientific data show that over 171 subjects suffering from various low back disorders performed the Trunk Velocity Test with no reported injuries or recurrence of pain. However, it is possible that you may experience some pain or exacerbation of symptoms, which may be prolonged
with this testing. In case this occurs, any discomfort should resolve well within the 5 minute recovery period. There are no direct benefits to participating in this study, however it is our hope that a new clinical instrument will be developed from this study for clinical assessment of low back pain problems.
Voluntary Participation
Participation in this study is on a voluntary basis and you are free to withdraw at any time for whatever reason. Withdrawal from the study will not affect your present or future medical care in any way.
All information obtained is strictly confidential and your anonymity will be protected at all times. A numerical code will be assigned to your file and the number will be used on all data related to you. The consent fonn and data will be stored separately in lacked files and be available only to the investigators. The information gathered may be used in scientific papers and presentations, but your name will not be used for either purpose. The records will not be used for any other purpose or disclosed to any third party without your permission.
The information included in this consent form has been explained to me by thc investigator to my satisfaction. 1 have had the opportunity to ask questions or seek other opinions. I am aware that if I have any questions or concerns regarding the study I may contact the investigators at the numbers provided above at any time and I will keep a copy of this form for my own information.
I have read and understand the explanation of the procedures of this study. I have had the opportunity to ask questions, which have been answered to my satisfaction. I am voluntarily signing this consent form to participate in this study.
I have carefully explained to the subject the nature of the above research study.
Date: -------- ----------------- Signature of the Investigator: ---------------------- -----------------
Multiple Regression Analysis I
Maximum ROM Flexion
Correlations
Pearson Correlation ROMLMM-RTP
I ROMLMM-FTP I 15 1 15
ROMLMM-FTP N ROMLMM-RTP
Model Summary
ROMLMM-RTP 1 .OOO
I Std. Errr of I I Adjusted R
ROMLMM-FTP .856
.856 15
I Model I R I R Square ( Square ( Estimate I
1 .OOO 15
a. Predictors: (Constant), ROMLMM-FTP
a. Predictors: (Constant), ROMLMM-FTP
b. Dependent Variable: ROMLMM-RTP
Model 1 Regression
Residual
Sum of Squares
482.450 175.284
Model 1 (Constant)
ROMLMM-FTP
d f 1
13
a. Dependent Variable: ROMLMM-RTP
Unsbndardized Coefficients
Mean Square 382.450
13.483
Standardb ed
Coefficient s
I
Beta
.856
8 11.043
.453
Std. Error 5.349
.076
F 35.781
t
2 .064 5.982
Sig. .OOOa
Sig . .060 .OOO
Regression - Peak Velocity
Correlations
I VELLMM-FTP I -871 1 1.000 I Pearson Correlation VELLMM-RTP
Model Summary
VELLMM-RTP 1 .OOO
N VELLMM-RTP VELLMM-FTP
1 Std. Er of 1 / Adjusted R
VELLMM-FTP .871
1 Model I R 1 R Square 1 Square I Estimate I
15 15
a. Predictors: (Constant), VELLMM-FTP
15 15
a. Predictors: (Constant), VELLMM-FTP
b. Dependent Variable: VELLMM-RTP
Model 1 Regression
Residual
i Total
Mean Square 1987.966
48.567
Model 1 (Constant)
VELLMM-FTP ,
Sum of Squares ,,
1987.966 63 1.367
2619.333
d f 1
13 14
F 40.933
a. Dependent Variable: VELLMM-RTP
Sig . .OOOa
I
Unstandardized Coefficients
Standardiz ed
Coefficient s
Beta
- .87 1
B 69.932
,186
Std. Enor 6.767
,029
t 10.334 6.398
Sig . -000 .ooo
Regression - Peak Acceleration
Correlations
Poarson Conelation ACCLMM-RTP
I ACCLMM-FTP I 15 1 15
ACCLMM-FTP N ACCLMM-RTP
Model Summary
ACCLMM-RTP 1.000
( Std. :;or of ( 1 Adjusted R
ACCLMM-FTP .873
.873 15
1 .OOO
15
a. Predictors: (Constant), ACCLMM-FTP
Model 1
*
R .873=
Model 1 Regression
Residual Total
Model 1 (Constant)
ACCLMM-FTP
R Square .762
a. Predictors: (Constant), ACCLMM-FTf
b. Dependent Variable: ACCLMM-RTP
Sum of Squares
347928.381 108378.552 456306.933
a. Dependent Variable: ACCLMM-RTP
square - .744
d f 1
13 14
Mean Square
347928.381 8336.812
Unstandardized Coefficients
Estimate 91.3061
Standardiz ed
Coefficient s
Beta
- .873
B -66.569
.397
F 41.734
Std. Error 83.207
- .061
Sig . .OOOa
t -. 800 6.460
Sig . .438 ,000
Consent Form 111
Title of the subjects"
Miucio Marqal, PT, MSc. Ph.D. Candidate 545-2658 - School of Physical and Health Education 544- 1300 - Home
Joan Stevenson, Ph.D. - School of Physical and Heath Education - Queen's University - 545-6288
Pat Costigan, Ph.D. - School of Physical and Heath Education - Queen's University - 545-6603
Study: "Study of the hunk velocity test in healthy and low back pain
Purpose of the study
The purpose of this study is determine whether spinal kinematic variables will be different or not in healthy and low back pain subjects.
Procedures Involved
You will spend approximately 1 hour to complete all the measurements, which will take place at the Biomechanics lab, School of Physical and Health Education, Queen's University.
You will be asked to answer a low back pain and a work information questionnaire and also to use a pain scale to show your level of pain aAer and before the test.
You will also be asked to perform a series of tests: Physical measurements which include height, weight, etc; Fastrak set up - Four sensors will be placed on your back and you will be asked to perform trunk velocity test - You will flex and extend the trunk in the sagittal plane as quickly as comfortably possible for 5 repetitions (one trial). two trials will be collected with two minute rest between trials. You can stop the test any time you feel pain or discomfort.
Risks and Benefits
There is minimal risk of injuries in all tests. Previous scientific data show that over 171 subjects suffering from various low back disorders performed the Trunk Velocity Test with no reported injuries or recurrence of pain. However, it is possible that you may experience some pain or exacerbation of symptoms, which may be prolonged with this testing. In case this occurs, any discomfort should resolve well within the 5 minute recovery period. There are no direct benefits to participating in this study, however it is our hope that a new clinical instrument will be developed from this study for clinical assessment of low back pain problems.
Voluntary Participation
Participation in this study is on a voluntary basis and you are free to withdraw 81
any time for whatever reason. Withdrawal from the study will not affect your present or future medical care in any way.
Confidentiality
All information obtained is strictly confidential and your anonymity will be protected at all times. A numerical code will be assigned to your file and the number will he used on all data related to yoil. The consent form end data will be storcd scpamtcl y in locked files and be available only to the investigators. The information gathered may be used in scientific papers and presentations, but your name will not be used for either purpose. The records will not be used for any other purpose or disclosed to any third party without your permission.
The information included in this consent form has been explained to me by the investigator to my satisfaction. I have had the opportunity to ask questions or seek other opinions. I am aware that if I have any questions or concerns regarding the study I may contact the investigators at the numbers provided above at any time and I will keep a copy of this form for my own information.
I have read and understand the explanation of the procedures of this study. 1 have had the opportunity to ask questions, which have been answered to my satisfaction. I am voluntarily signing this consent form to participate in this study.
I have carehlly explained to the subject the nature of the above research study.
Pain Scale
Subject Code: Date:
Please use the scale below to rate the intensity of you back pain. Circle the number that
best describe your pain right now.
0 1 2 3 4 5
No pain Extremely intense
Pain Scale
Subject Code: Date:
Please use the scale below to rate the intensity of you back pain. Circle the number that
best describe your pain right now.
No pain Extremely intense
Working Condition Questionnaire
Subject Code:
1 - Have you had low back pain in the past two years?
7.
-1 Yes
1- Are you currently employed?
O Yes
(If No, stop here)
3- Are you currently:
- L_1 Working
[3 On sick-leave due to low back pain
5 Ondisability duetolowbackpain
(If you are currently working answer the next question)
Date:
4- Have your duties been modified due to your low back pain condition'?
O yes O NO
Multiple Regression Analysis II
Stepwise Multiple Regression - LBP X Disability
Variables EnteredlRsrnoveda
- Model
Variables Entered
PKTHVEL
PEKTLACC
PKLUVEL
Variables Removed
- -
Method
Stepwise (Criteria: Probability- of-F-to-ente r <= .050, Probability- of-F-to-rern ove >= 100).
Stepwise (Criteria: Probability- of-F-to-ente r <= .050, Probability- of-F-to-rem ove >= .loo).
Stepwise (Criteria: Probability- of-F-to-ente r <= .050, Probability- of-F-to-fern ove >= 100).
a. Dependent Variable: OSWESTRY SCORE
Model Summary
Model Summary
Model
a. Predictors: (Constant), PKTHVEL
b. Predictors: (Constant), PKTHVEL, PEKTLACC
c. Predictors: (Constant), PKTHVEL, PEKTLACC, PKLUVEL
R
Model I
1 2 3
1 I .553a
b. Predictors: (Constant), PKTHVEL, PEKTLACC
R Square
Model 1 Regression
Residual Total
2 Regression Residual Total
3 Regression Residual
i Total
c. Predictors: (Constant), PKTHVEL, PEKTLACC, PKLUVEL
,306
_
Change Statistics
d. Dependent Variable: OSWESTRY SCORE
Adjusted R Square
a. Predictors: (Constant), PKTHVEL
Sum of Squares 3662.203 8312.706
1 1974.909 5588.306 6386.603
1 1 974.909 6245.574 5729.335
1 1974.909
Std. Error of the
Estimate .289
R Square Change
,306 . I61 .055
14,0685
F Change 18.503 12.365 4.589
dfl 1
1
I
d f 1
42 43
2 41 43
3 40 43
df2 42 41 40
Sig. F Change
.OOO
.001
- .038
Sig . .OOOa
.OOob
.00Oc
Mean Square 3662.203
197.922
2794.153 155.771
2081.858 143.233
F 18.503
17.938
14.535
Model 1 (Constant)
PKTHVEL 2 (Constant)
PKTHVEL PEKTLACC
3 (Constant) PKTHVEL PEKTtACC PKLUVEL
a. Dependent Variablc OSWESTRY SCORE
t 11.219 -4.302 1 1.966 -4.612 -3.516 12.175 4.653 -3.265 -2.142
f
Correlations
Standardiz ed
Coefficient s
.. Beta
-S53
-.527 -.402
-.511 -.363 -.238
Unstandardized Coefficients
Sig. .OOO .OOO -000 .OOO .OO 1 .OOO .OOO .002 .038
8 55.81 1 -.212
68.746 - .202
.1.24 1 E-02 74.4 17 -.I96
, I . 121 E-02 6.853E-02
Std. Error 4.975 .049
5.745 .044 .004 6.1 12 .042 -003 -032 _
Zero-order
-553
-.553 -.436
-.553 -.436 -.339
Partial
-2553
-.584 - .48 1
-.593 -.459 -.321
Part
-553
-.526 -.401
-.SO9 -.357 -,234
Excluded aria blesd
hodel PKTHDISP PEKTHACC PKTLDISP PKTLVEL PEKTUCC PKLUDISP PKLUVEL PEKLUACC PKSADISP PKSAVEL PEKSAACC
Z PKTHDISP PEKTHACC PKTLDISP PKTLVEL PKLUDISP PKLUVEL PEKLUACC PKSADISP PKSAVEL PEKSAACC
3 PKTHDISP PEKTHACC PKTLDISP PKTLVEL PKLUDISP PEKLUACC PKSAOt SP PKSAVEL PEKSAACC
Beta In -.006a 1 0oa -.226a -.34Ga -.402= -. 1 5za -.298a -.3Oza -.257a -.21 7a -.22Fi2
a. Predictors in the Model: (Constant), PKTHVEL
Sig . .972 .594 .080 .008 ,001 ,247 -01 9 .028 .045 .094 .092
Partial :orrelation
-.005 .084 -.270 -.397 -.481
-.I80 -.357 -.335 -. 308 -.259 -.260 .I01
-106 -.039 -.098 -.079 -.321 - .25 1 -.242 -.221 -.I85
>ollinearit Statistics
rolerance 532 .488 .985 ,913 .996 .9R 1 ,994 .a53 ,994 .985 .925
b. Predictors in the Model: (Constant), PKTHVEL, PEKTLACC
c. Predictors in the Model: (constant), PKTHVEL, PEKTLACC, PKLUVEL
d. Dependent Variable: OSWESTRY SCORE
Consent Form IV
Investiaator: Mkcio Marqal, PT, MSc. Ph.D. Candidate 545-2658 - School of Physical and Health Education 544- 1300 - Home
Suoervisors: Joan Stevenson, Ph.D. - School of Physical and Heath Education - Queen's University - 545-6288
Pat Costigan, Ph.D. - School of Physical and Heath Education - Queen's University - 545-6603
Title of the Study: "Queen's-Dupont study: Use of the trunk velocity test in a longitudinal study"
Purpose of the study
The purpose of this study is determine whether spinal kinematic variables will be different or not in workers that developed low back pain.
Procedures Involved
You will spend approximately 1 hour to complete all the measurements, which will take place at Dupont Canada.
You will also be asked to perform a series of tests: I ) Physical measurements which include height, weight, etc; 2) Fastrak set up - Three sensors will be placed on your back and you will be
asked to perform trunk velocity test - You will flex and extend the trunk in the sagittal plane as quickly as comfortably possible for 5 repetitions (one trial). two trials will be collected with two minute rest between trials.
Risks and Benefits
There is minimal risk of injuries in all tests. Previous scientific data show that over 171 subjects suffering from various low back disorders performed the Tnink Velocity Test with no reported injuries or recurrence of pain. However, it is possible that you may experience some pain or exacerbation of symptoms, which may be prolonged with this testing. In case this occurs, any discomfort should resolve well within the 5 minute recovery period. There are no direct benefits to participating in this study. however i t is our hope that a new clinical instrument will be developed from this study for clinical assessment of low back pain problems.
Voluntary Participation
Participation in this study is on a voluntary basis and you are free to withdraw at any time for whatever reason. Withdrawal from the study will not affect your present or future medical care in any way.
Confidentiality
All information obtained is strictly confidential and your anonymity will be protected at all times. A numerical code will be assigned to your file and the number will be used on all data related to you. The consent form and data will be stored separately in locked files and bc available only ts the investigators. Thr ialonnation gathered may be used in scientific papers and presentations, but your name will not be used for either purpose. The records will not be used for any other purpose or disclosed to any third party without your permission.
The information included in this consent form has been explained to me by the investigator to my satisfaction. I have had the opportunity to ask questions or seek other opinions. I am aware that if I have any questions or concerns regarding the study I may contact the investigators at the numbers provided above at any time and I will keep a copy of this form for my own information.
1 have read and understand the explanation of the procedures of this study. 1 have had the opportunity to ask questions, which have been answered to my satisfaction. 1 am voluntarily signing this consent f o m ~ to participate in this study.
I have carefully explained to the subject the nature of the above research study.