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Effects of Task-Specific Locomotor and

Strength Training in Adults Who WereAmbulatory After Stroke: Results ofthe STEPS Randomized Clinical TrialKatherine J Sullivan, David A Brown, Tara Klassen, Sara Mulroy, Tingting Ge,Stanley P Azen, Carolee J Winstein; for the Physical Therapy Clinical ResearchNetwork (PTClinResNet)

Background and PurposeA phase II, single-blinded, randomized clinical trial was conducted to determine the

effects of combined task-specific and lower-extremity (LE) strength training to im-prove walking ability after stroke.

SubjectsThe participants were 80 adults who were ambulatory 4 months to 5 years after aunilateral stroke.

MethodThe exercise interventions consisted of body-weightsupported treadmill training(BWSTT), limb-loaded resistive leg cycling (CYCLE), LE muscle-specific progressive-resistive exercise (LE-EX), and upper-extremity ergometry (UE-EX). After baselineassessments, participants were randomly assigned to a combined exercise program

that included an exercise pair. The exercise pairs were: BWSTT/UE-EX, CYCLE/UE-EX, BWSTT/CYCLE, and BWSTT/LE-EX. Exercise sessions were 4 times per week for6 weeks (total of 24 sessions), with exercise type completed on alternate days.Outcomes were self-selected walking speed, fast walking speed, and 6-minute walk

distance measured before and after intervention and at a 6-month follow-up.

ResultsThe BWSTT/UE-EX group had significantly greater walking speed increases compared

with the CYCLE/UE-EX group; both groups improved in distance walked. All BWSTTgroups increased walking speed and distance whether BWSTT was combined with LEstrength training or not.

Discussion and ConclusionAfter chronic stroke, task-specific training during treadmill walking with body-weightsupport is more effective in improving walking speed and maintaining these gains at6 months than resisted leg cycling alone. Consistent with the overtraining literature,LE strength training alternated daily with BWSTT walking did not provide an addedbenefit to walking outcomes.

View video clips related to thisarticle at www.ptjournal.org

KJ Sullivan, PT, PhD, is AssociateProfessor of Physical Therapy, Di-vision of Biokinesiology and Phys-

ical Therapy at the School of Den-tistry, University of SouthernCalifornia, 1540 E Alcazar St, CHP-155, Los Angeles CA 90089 (USA).

Address all correspondence to DrSullivan at: [email protected].

DA Brown, PT, PhD, is AssociateProfessor, Department of PhysicalTherapy and Human MovementSciences, The Feinberg School ofMedicine, Northwestern Univer-sity, Chicago, Ill.

T Klassen, PT, MS, NCS, is ClinicalInstructor, Department of PhysicalTherapy, University of British Co-lumbia, Vancouver, British Colum-bia, Canada.

S Mulroy, PT, PhD, is Director,Pathokinesiology Laboratory, Ran-cho Los Amigos National Rehabil-itation Center, Downey, Calif.

T Ge, MS, is Doctoral Student, De-partment of Preventive Medicine,Keck School of Medicine, Univer-sity of Southern California.

SP Azen, PhD, is Professor, Depart-ment of Preventive Medicine,Keck School of Medicine, Univer-sity of Southern California.

CJ Winstein, PT, PhD, FAPTA, isProfessor, Division of Biokinesiol-ogy and Physical Therapy at theSchool of Dentistry, and Depart-ment of Neurology, Keck Schoolof Medicine, University of South-ern California.

Physical Therapy Clinical ResearchNetwork (PTClinResNet) (see listof investigators on page 1598).

[Sullivan KJ, Brown DA, Klassen T,et al; for the Physical Therapy Clin-ical Research Network (PTClinRes-Net). Effects of task-specific loco-motor and strength training inadults who were ambulatory afterstroke: results of the STEPS ran-domized clinical trial. Phys Ther.2007;87:15801602.]

2007 American Physical TherapyAssociation

Research Report

Post a Rapid Response orfind The Bottom Line:www.ptjournal.org

1580 f Physical Therapy Volume 87 Number 12 December 2007


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Impaired walking ability is a hallmarkresidual deficit following stroke. Al-though approximately 70% to 80%

of adults who have survived a stroke will recover the ability to walk short

distances on flat surfaces, only 50%achieve even limited communityambulation1 and fewer than 20% haveunlimited ambulation in the communi-ty.2 In the early period following astroke, lower-extremity (LE) paresisfrom impaired muscle activation limits

the ability to advance the limb forswing and to support body weightduring stance.3,4 As time from strokeincreases in the early poststroke pe-riod, motor control, muscle strength(force-generating capacity), and walk-

ing ability begin to improve.5 In-complete recovery and developmentof secondary impairments, however,

may contribute to continued gait dys-function.4,6,7 In addition to paresis,stroke disrupts selective voluntarycontrol and can leave the patient withprimitive patterns of muscle actionand spasticity.8 Disuse muscular atro-phy compounds the initial neuro-logical injury, and muscle weaknessremains prevalent despite some

functional recovery during the acutephase.9 The net effect of these impair-ments on walking is reduced speedand endurance, with impaired stabilityand asymmetry, during gait. Conse-quently, self-selected walking speed isa strong overall indicator of bothstroke severity10,11 and communityambulation status.2

Impairment in muscle strength isthought to be an important limitingfactor in determining walking speedafter stroke. There is a positive cor-relation between muscle strengthand maximum gait speed.7,1114 Spe-cific muscle groups that demonstratethe strongest relationship with walk-

ing speed vary greatly among stud-ies, depending on the number ofmuscles investigated, the parameterused to quantify strength (ie, handdynamometer force, isometric or iso-kinetic torques), and the method of

documenting gait speed (eg, self-selected or fast speeds, distance

walked, with or without assistive de-

vices or orthoses).7,1114 Studies thathave compared multiple muscle

groups most frequently have identi-fied strength in the hip flexors15 andankle plantar flexors7,12 as the stron-gest predictor of walking speed afterstroke, although strength in the kneeextensors,14,16,17 hip extensors,13

and ankle dorsiflexors18 was identi-

fied as being significantly related togait speed. The contribution of thehip flexors and ankle plantar flexorsto maximizing walking speed hasbeen related to their large bursts ofpower generation late in the stance

phase of the gait cycle.7,15,19,20

Muscle strength training may lead to

improvement in both lower-limbstrength and gait speed, althoughcontrolled studies that isolate this in-tervention are lacking. Programs thatcombined muscle strength training

with stretching, balance training,and aerobic conditioning have dem-onstrated significant improvementsin walking function.2123 However,

because the protocols were multi-faceted, it is not possible to deter-mine the precise role that thestrength training component mayhave played in improving walkingfunction. Interventions of musclestrengthening for a single musclegroup after stroke have demon-strated increased muscle strength,

but little or no improvement in walk-ing speed.24 Several studies21,2527

demonstrated that strength trainingof multiple LE muscle groups pro-duced significant increases instrength, resulting in modest func-tional changes in walking distance orimproved balance or sit-to-stand abil-ity, but did not increase walking

speed. In a study of individuals withmild stroke severity (ie, baseline

walking speeds of approximately0.80 m/s), a program of progressiveLE strengthening using functional

weight-bearing activities such as step

climbing and single-limb heel raisesfor exercise produced moderate in-creases in walking speed that were

significantly correlated with in-creased strength in the paretic hip

flexors, knee extensors, and ankleplantar flexors.28 None of these stud-ies compared effects of muscle-specific strengthening protocols orinterventions that used resistedlocomotor-like activities such as aloaded cycling task. In addition, no

studies have combined task-specificlocomotor training with varioustypes of LE strength training such asthese.

Task-specific training is the repeti-

tive practice of a task that is specificto the intended outcome. Repeti-tive stepping on a treadmill is an ex-

ample of task-specific gait trainingthat appears to be critical to theachievement of improved walkingspeeds.23,25,29,30 Visintin et al31 dem-onstrated that treadmill training with40% body-weight support (BWS)provided in early training that wasprogressively decreased over train-ing sessions resulted in better walk-

ing outcomes after stroke than tread-mill training without BWS.

A recent Cochrane meta-analysis32

and an evidence-based systematic review conducted by Foley et al33 ofthe Canadian Stroke Network bothconcluded that there is conflicting(level 4) evidence that treadmill

training with or without BWS im-proves walking activity after stroke.

Across these 2 reviews, 9 random-ized clinical trials (RCTs) specificallyinvestigated treadmill training withBWS. There were large disparitiesamong the trials in terms of the ex-ercise parameters specified in the in-tervention protocols (ie, frequency,

intensity, and duration). Frequency(the number of sessions in a week)

varied from 3 times per week34,35 to4 times per week31 to 5 times per

week.3640 Training intensity can bequantified by measuring within-

Locomotor and Strength Training in Adults Who Were Ambulatory After Stroke

December 2007 Volume 87 Number 12 Physical Therapy f 1581


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session attributes such as walkingtime and treadmill speed. Actual

walking time was reported in only 5

of the 9 RCTs and varied from 14 to30 minutes of total walking time,

with or without restbreaks.31,32,35,38,40 Treadmill walkingspeed varied from 0.22 to 1.1 m/s(0.52.5 mph) across the RCTs, withonly one RCT that specified speedscloser to functional walkingspeeds.35 The duration across all

RCTs ranged from 10 to 68 sessions.Recent studies35,41,42 have consis-tently shown that treadmill training(with or without BWS) at higherspeeds (ie, higher intensity) is moreeffective at improving walking after

stroke than training at slowerspeeds. Therefore, a major limitationto the conclusions from the system-

atic reviews of treadmill training af-ter stroke that were conducted priorto these more recent studies is thelack of consistency and intensity inthe intervention and specified proto-cols. Due to this conflicting evi-dence, we specifically designed thisstudy to address the evidence relatedto treadmill training with BWS as our

intervention of task-specific training.

The design of our poststroke walkingrehabilitation study was influencedby the literature on LE strengthtraining and task-specific locomotortraining. We posed 2 distinct clini-cal questions, each with a specifichypothesis. First, we wanted to de-

termine whether a resisted cyclingprogram that incorporated some ofthe weight-bearing and task-relateddemands of walking in a cyclicalleg cycling task as described byBrown et al43 was as effective inimproving walking outcomes inadults with chronic stroke whohad walking disability (ie, walking

speeds at 33% of adult norms) as ahigh-intensity, task-specific treadmilltraining protocol with BWS. As thiscycling exercise uses whole-limb cy-clic locomotor-like movements thatemphasize LE extensors and flexors

as muscle groups, the effectivenessof a resisted cycling task to improve

walking after stroke is an important

and relevant clinical question be-cause the cost of additional person-

nel and workload demands on theclinician of body-weightsupportedtreadmill training (BWSTT) are high.If a resisted cycling task can achievethe same walking outcomes in indi-

viduals after stroke, then a morecost-effective treatment option may

be identified.

Second, we wanted to determine whether walking outcomes afterstroke would be enhanced if ahigh-intensity, task-specific locomo-

tor training program was combinedwith a moderately high progressive-resistive LE exercise program. There-

fore, we developed 2 interventionprograms that combined the BWSTTprotocol with resistive exercise pro-grams that are representative of op-tions physical therapists may have inthe clinic. One intervention programcombined BWSTT with the resistedcycling task described above. Theother intervention program com-

bined BWSTT with a muscle-specificprogressive-resistive exercise proto-col designed to strengthen the pa-retic hip flexors and extensors, kneeflexors and extensors, and ankle dor-siflexors and plantar flexors. This re-sisted exercise program used the 10-repetition maximum (RM), withloading provided by equipment typ-

ically present in the clinic such aselastic bands of varying resistanceand cuff weights, and includedmuscle-specific exercises that clini-cians use with their patients.

The challenge for using a muscle-specific resistive exercise program inindividuals with stroke is the motor

control problem associated with lossof movement selectivity. Therefore,

we designed an exercise program in-corporating movement activationbased on the individuals movementcapability that was either indepen-

dent or within synergy movementpatterns, as determined by the motortasks of the lower-extremity Fugl-

Meyer (LE-FM) motor assessment.

Finally, we designed an upper-extremity (UE) ergometry exercisethat was to serve as a sham task tobe combined with the BWSTT andresisted cycling exercise. Previousstudies that have used low-intensityUE exercise as a comparison control

have demonstrated that there is noeffect of low-intensity UE exerciseon walking outcomes.23,25 There issubstantial evidence that physicaltherapy interventions that include in-tensive, task-specific strength or en-

durance training are more effectivethan standard care or no care.4447

Therefore, there is little value in

comparing interventions with a no-treatment control. In contrast, thedesign of meaningful rehabilitationclinical trials requires the use of aparallel trial paradigm.48 A paralleltrial design includes the random as-signment of study participants into 2or more intervention groups that areequated for exposure both to the

therapeutic intervention as well as tothe therapist. This design discrimi-nates between the positive changesin behavior that occur when a per-son is being observed49 and the hy-pothesized treatment effect50 andcan result in clinical trials that have

practical clinical relevance.51,52

The Strength Training EffectivenessPost-Stroke (STEPS) RCT was de-signed to make specific comparisonsamong 4 intervention groups that

were equated for frequency (4 ses-sions per week), intensity (1 hour ofmoderate-intensity, task-specific gaittraining or strengthening exercise),and duration (6 weeks for a total of

24 sessions) and included interven-tions that are available and gainingpopularity in the clinic despite thelack of strong evidence of their ef-fectiveness. The use of this designshould provide valuable compari-




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sons that reveal the practical benefitsof task-specific training or combinedprograms to improve walking out-

comes after stroke. Thus, we pro-posed 2 separate a priori hypothe-

ses. First, we hypothesized that aresisted limb-loaded cycling task thatincorporated locomotor-like move-ments would be as effective at im-proving walking outcomes (ie, speedand distance) as a high-intensity,task-specific intervention of treadmill

training with BWS. Second, we hy-pothesized that intervention programsthat combine moderate-intensitystrengthening (ie, resisted cycling ormuscle-specific strengthening) withtask-specific training (ie, BWSTT in

this study) would be more effective atimproving walking outcomes thantask-specific training alone.

MethodParticipantsEighty participants with chronicstroke were recruited for this phaseII, single-blinded, multisite, random-ized intervention trial from strokegroups and outpatient clinics inthe greater Los Angeles, Calif, and

Chicago, Ill, communities. Threestudy sites participated: (1) Univer-sity of Southern California (USC), Di-

vision of Biokinesiology and PhysicalTherapy, Los Angeles, Calif; (2) Ran-cho Los Amigos National Rehabilita-tion Center (RLANRC), Pathokinesiol-ogy Lab, Downey, Calif; and (3)Northwestern University (NU), De-

partment of Physical Therapy and Hu-man Movement Sciences, Chicago, Ill.

Participants who were beyond theperiod of spontaneous neurologic re-covery and who were ambulatorybut had significant walking disabilitythat limited their community ambu-lation were screened for eligibility

based on the following a priori in-clusion criteria: (1) age 18 years orolder; (2) 4 months to 5 years afterfirst-time onset of a ischemic or hem-orrhagic cerebrovascular accident(CVA) confirmed by computed to-

mography, magnetic resonance im-aging, or clinical criteria; (3) able toambulate at least 14 m with an as-

sistive or orthotic device and assis-tance of one person (minimum of

Functional Ambulation Classificationlevel II) with a self-selected walkingspeed of 1.0 m/s; (4) voluntarilyprovided informed consent; and (5)approval of their primary care physi-cian to participate.

Exclusion criteria included healthconditions that would interfere withsafe participation in a moderatelyhigh exercise program or recent ex-ercise study participation that mightinterfere with the treatment effects

of our protocol. Specific exclusionsincluded: serious medical condi-tions; resting systolic blood pressure

greater than 180 mm Hg, resting di-astolic blood pressure greater than110 mm Hg, or resting heart rategreater than 100 bpm*; lower-limborthopedic conditions such as prior

joint replacement or limitations inrange of motion; spasticity manage-ment that included botulinum toxininjection (4 months earlier) or

phenol block injection (12 monthsearlier) to the affected LE and intra-thecal baclofen or oral baclofen(within the past 30 days); Mini-Mental State Exam score of24; cur-rently receiving LE strengtheningexercises or gait training; past partic-ipation in any study examining theeffects of long-term BWSTT (4

weeks of training); limb-loaded ped-aling or LE strengthening; or plans to

move out of the area within the next year or no transportation to thestudy site for all evaluations and

intervention sessions.

Study Design andOutcome MeasuresInformed consent was approved bythe institutional review board ofeach institution. After informed con-sent was obtained and baseline as-

sessments were completed, partici-pants were balanced for walkingseverity based on self-selected over-ground walking speed (severe: 0.5m/s or moderate:0.5 m/s but 1.0m/s) and randomly assigned to 1 of 4

comparison exercise groups that in-cluded 4 treatment sessions per

week for 6 weeks (total of 24 treat-

ment sessions). Severity strata cut-offs were determined a priori basedon a previous pilot study.35 Severity

was balanced within groups to en-sure that numbers of participants atmoderate and severe levels were notdisproportionate between groups;stroke severity is a factor that hasbeen demonstrated to affect respon-

siveness to locomotor training.29,35

Baseline measures of patient demo-graphics, stroke characteristics(including onset), and outcomemeasures were assessed prior to ran-domization to treatment group. Allmeasurements were performed byphysical therapists who were trained

to perform standardized assessmentprocedures and blinded to group as-signment; these therapists did notprovide the interventions. Consis-tent with the health impact of dis-abling conditions adopted by thePhysical Therapy Clinical ResearchNetwork (PTClinResNet), outcomemeasures were selected to measure

relevant poststroke outcomes at theprimary body function, activity, andparticipation levels of the Interna-tional Classification of Functioning,

Disability and Health.55 Outcomemeasures were selected based on

* Cardiovascular exclusions and preexerciseand postexercise tolerance guidelines werebased on findings of a previous study of exer-cise training in individuals with stroke53 andare consistent with the American College ofSports Medicine Guidelines for Exercise Test-ing and Prescription.54 In addition, becausegraded exercise testing with an electrocardio-graph was not conducted in our study, medi-cal clearance was required by a primary carephysician or cardiologist for each participant.If indicated by the personal physician, moreconservative cutoffs for systolic blood pres-sure and diastolic blood pressure were usedfor exercise termination.




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their known reliability and validity inthe population of adults with stroke.

The primary outcome measure wasoverground self-selected walking

speed.2,56

Secondary walking out-come measures were fast-walkingspeed and 6-minute walk distance.57,58

Walking speed was determined bythe therapist as the participantstime (measured in seconds with astopwatch) to walk the middle 10 m

of a 14-m walkway with the assistivedevice or ankle-foot orthosis typi-cally used for community ambula-tion. Data for 2 trials were collectedfor the self-selected pace followedby collection of data for 2 trials for

the fast pace. Measurements for bothtrials were averaged for each re-spective walking speed. Six-minute

walk distance was determined by thetherapist as the distance that the par-ticipant walked in 6 minutes withthe typically used assistive device orankle-foot orthosis on an oval walk-

way between 2 chairs positioned18 m apart. Standardized encourage-ment was provided at each minute,and participants could stop and rest

at 1 of 4 chairs positioned on thewalkway.

Additional secondary outcome mea-sures included the LE-FM motorscore59; Berg Balance Scale60; the 16-item Stroke Impact Scale (SIS-16),

version 3.061,62; Medical OutcomesStudy 36-Item Short-Form Health

Survey (SF-36), version 2.0 (physicalhealth and mental health compo-nents)62,63; and LE isometric peaktorque (bilateral hip flexors, hip ex-tensors, knee flexors, knee exten-sors, and ankle dorsiflexion andplantar flexion).64

We decided to measure isometric

torque due to the known deficits inmovement selectivity after strokeand the range of motor severity weexpected to observe in our partici-pants. Isometric torque was mea-sured, bilaterally, on a Biodex

dynamometer, with test positionsselected based on optimal anatomi-cal muscle length (ankle plantar flex-

ion at 5, ankle dorsiflexion at 15 ofdorsiflexion, knee flexion and exten-

sion at 45 of knee flexion, hip flex-ion at 60 of hip flexion, hip exten-sion at 90 of hip flexion) and bodystability considerations. Hip torque

was measured with participants in asupine position, and knee and ankletorque were measured in the seated

position with both the knees andhips flexed to 90 degrees. Prior toeach measurement, the weight ofthe limb due to gravity was mea-sured and subtracted from the re-corded measurement. Participants

were instructed to perform the iso-metric muscle contractions as hardas they could and then rest for about

1 minute between the 3 efforts.Three peak torque measurements

were taken from each muscle groupand averaged for data analysis.

The primary and secondary walkingoutcome measurements were col-lected at baseline, after 12 treat-ment sessions, after 24 treatment

sessions, and at the 6-month follow-up. All other outcomes were mea-sured at baseline, after treatment,and at a 6-month follow-up, exceptfor SIS scores, which were obtainedonly at baseline and at the 6-monthfollow-up.

Only the primary and secondary

walking outcomes from the activity-level measures related to walkingspeed and endurance will be pre-sented in this article, along withcomposite extensor and flexor iso-metric muscle torque measurements(ie, the sum of the 3 extensor torque

values and the sum of the 3 flexortorque values) as an explanatory vari-

able from the body function level. We elected to analyze compositestrength scores rather than individ-

ual muscle torques because thestrengthening interventions tested inthis study target either whole-limb

activities (limb-loaded cycling andtreadmill training) or specific muscle

groups but are individualized basedon each participants initial patternof weakness. We separated compos-ite scores into extensor and flexorscores because these muscles tendto work together both in functionand in the whole-limb exercises.

Moreover, the magnitude of torqueproduction is greater in the exten-sors than in the flexors, and separatecomposites would prevent thechanges in extensor torques fromobscuring the changes in the flexor

values.

InterventionsThe goal of the treatment sessions

was to have each participant engagein a 1-hour physical therapy programthat included a moderate-intensityprogressive exercise protocol that isrepresentative of what therapistsmay do in a usual treatment session.Intervention consisted of physicaltherapistsupervised exercise con-

ducted in 1-hour sessions, 4 days per week, for 6 weeks. Protocol varia-tions for missed visits were accept-able if the total 24 visits were accom-plished within an 8-week period.

Four exercise interventions wereused. Three exercise interventions

were designed to improve gait speed

or LE strength, and one UE exerciseintervention was designed as a shamintervention, not to include any ac-tive component that would improvegait speed or LE strength. The exer-cise interventions were: (1) BWSTT,(2) limb-loaded resistive leg cycling(CYCLE), (3) LE muscle-specificprogressive-resistive exercise (LE-

EX), and (4) UE ergometry (UE-EX).(For video clips of these exercises,

visit this article online at www.ptjournal.org). After baseline assess-ments, participants were randomlyassigned to a combination exercise

Biodex Medical Systems Inc, 20 Ramsay Rd,Shirley, NY 11967-4704.




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program that consisted of the follow-ing exercise pairs: BWSTT/UE-EX,CYCLE/UE-EX, BWSTT/CYCLE, and

BWSTT/LE-EX. Participants engagedin the exercise 4 days per week. Ex-

ercise type was on alternate days (eg,BWSTT session on one day followedby CYCLE session on the alternateday). Based on participant prefer-ence, a rest day was provided on

Wednesday or Friday, with no exer-cise on the weekend.

All participants received the samenumber of treatment sessions andcontact time with a physical thera-pist in order to minimize the Haw-thorne effect.49 Two separate com-

parisons were conducted: (1)BWSTT/UE-EX and CYCLE/UE-EXand (2) BWSTT/UE-EX, BWSTT/

CYCLE, and BWSTT/LE-EX. The firstcomparison examined the efficacy oftask-specific treadmill training withBWS compared with a resistive cy-cling program that emphasized LEstrengthening of muscle groups usedin gait. The second comparison al-lowed for an analysis of the efficacyof an exercise program that com-

bines task-specific treadmill training with BWS with a progressive-resistive exercise program (eitherresistive LE cycling or LE muscle-specific progressive-resistive exer-cise) compared with task-specifictreadmill training with BWS alone.

A brief description of each interven-

tion is provided below and in the Appendix. A detailed descriptionof methods, progression algorithms,and response to treatment will fol-low in subsequent publications.

During the BWSTT protocol, the par-ticipant was fitted with a harness at-tached to an overhead suspension

system positioned over a treadmill.The BWSTT session required the par-ticipant to walk on a treadmill forfour 5-minute training bouts atspeeds within the range of 1.5 to 2.5mph to achieve 20 accumulated min-

utes of treadmill walking time overthe 1-hour intervention session. De-tails of the BWSTT protocol have

been described in a previous publica-tion.35As part of the task-specific train-

ing session, the participant receivedgait instruction in an overground set-ting over a 50-ft (15-m) distance, im-plemented specifically to reinforce thegait training that transpired while onthe treadmill. The BWSTT session wasprovided on either a Robomedica

(USC, RLANRC) or a Biodex (NU) un-weighting system.

The CYCLE training protocol re-quired the participant to cycle withthe LEs on a modified Biodex semi-

recumbent cycle. The apparatus hasa releasable seat, enabling it to slidealong a linear track where up to ten

10-lb bungee cords can be attachedto produce extensor muscle resis-tance similar to a leg press machine.Therefore, in addition to the regularcrank-based resistance encounteredduring pedaling exercise, the limbextensor muscles primarily are re-quired to overcome resistance tomaintain a stable body position

against the sliding seat. The goal ofthe exercise is for the participant topedal while keeping the sliding seatfrom moving forward out of the tar-get exercise region. If the forcesgenerated by the legs are not suffi-cient to overcome the pull of theseat, the seat will move forward outof the target region and the partici-

pant will be cued to push out backinto the exercise region.

Participants were asked to complete10 sets of 15 to 20 revolutions ineach session. Participants weregiven at least 2 minutes to rest be-tween sets, during which heart rate,blood pressure, and signs of distress

were monitored. The initial load set-ting was determined through a limbload test that counted how many cy-

cles the participant was able to suc-cessfully pedal with the seat base lo-cated in the exercise region. The

number of successful revolutionscompleted by the paretic limb deter-

mined the load setting for the nextset. After each set, the number ofsuccessful revolutions on the pareticlimb was recorded. A successful rev-olution was defined as the comple-tion of one extension phase with theseat base remaining in the exercise

region. The load settings were adjusted using this guideline for theremaining sets in each session, asdescribed in the Appendix.

The LE-EX protocol required each

participant to isotonically exercisethe affected LE using external resis-tance (eg, gravity, resistive tubing,

cuff weights of various incre-ments). The therapist followed anexercise algorithm that accountedfor the participants strength as

well as movement synergy level todetermine a 10-RM for 6 specificmuscle groups (hip flexors, hip ex-tensors, knee flexors, knee exten-sors, ankle dorsiflexors, and ankle

plantar flexors). For example, thestarting position against gravity forthe ankle dorsiflexors was theLE-FM position for testing anklemovements independent of syn-ergy (ie, standing, knee extended,

with foot dorsiflexed against grav-ity). If the participant could isolateankle dorsiflexion in this position,

the typical procedure to determinea 10-RM was used, and the dorsi-flexor would be loaded with resis-tance typically used by a therapist(in this case, resistive tubing). Ifthe participant could not isolatethe dorsiflexors in the standing po-sition, then dorsiflexion againstgravity in a sitting position was

used (ie, the less difficult positionto activate the dorsiflexors in theLE-FM test). If the participant couldnot activate the dorsiflexors in asitting position, then the partici-pant was positioned supine and

Robomedica, One Technology Park, SuiteC-511, Irvine, CA 92618.




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used hip and knee flexion to activate the dorsiflexors.

Progression included moving to amore isolated movement position or

increasing resistance within a posi-tion where activation occurred. Dur-ing the LE-EX session, each musclegroup was exercised for 3 sets of 10repetitions at 80% of the 10-RM. Aprogression algorithm was used toincrease the workload across the 12

treatment sessions. The therapistprogressed the exercise by either in-creasing the load within an exercisetype or progressing the participantto the more difficult exercise-typelevel.

The UE exercise protocol requiredthe participant to cycle with the UEs

on an Endorphin EN-300 HandCycle. The therapist adjusted the re-sistance on the cycle to a level wherethe participant could complete 20revolutions, but no more (ie, 20-RM).The exercise session consisted of theparticipant completing 10 sets of amaximum of 20 revolutions. For-

ward and backward cycling were al-

ternated for each set of exercise, andthe therapist assisted the partici-pants hemiparetic UE with the cy-cling motion, as needed.

During intervention sessions, cardio-vascular response was monitored byheart rate and blood pressure mea-surements prior to exercise, immedi-

ately after each exercise bout, and atthe end of the exercise session. Priorto the start of exercise and at the endof the exercise session, each partici-pants heart rate and blood pressureneeded to be within the followingcardiovascular tolerance guidelines:

while sitting at rest, systolic bloodpressure had to be less than 180 mm

Hg, diastolic blood pressure had tobe less than 110 mm Hg, and heartrate had to be less than 100 bpm,

and, with standing, systolic bloodpressure could not drop more than20 mm Hg. Immediately after exer-

cise, the participants systolic bloodpressure had to be less than 200 mm

Hg and diastolic blood pressure hadto be below 110 mm Hg. Exerciseintensity was no greater than 80% ofage-predicted maximum heart rate; arest was provided if the individualperceived a high rate of exertion. Ifany of the previous cardiovascular

guidelines were not met, the exer-cise session was not started or, ifalready started, was stopped imme-diately. The participants primarycare physician was contacted if there

were abnormal responses to exer-

cise or if heart rate or blood pressurewas higher then what was typical forthe participant at rest. Medication

adjustment was provided by the phy-sician, if needed. If the physician orthe investigators felt that the exer-cise intensity was too high for anindividual, the participant was with-drawn from the study.

Each therapist passed a rigorousstandardization procedure on his or

her respective protocol before eval-uating or intervening with a par-ticipant in the STEPS study. Thestandardization process included at-tendance at training sessions to de-

velop psychomotor skills, video-taped performance of the therapistconducting the protocol on an indi-

vidual with stroke, and 90% compe-

tency rating by peer review on astandardized assessment rating scaleassessed by the research coordinatorfrom a cooperating site other thanthe therapists home site.

Adverse Event MonitoringDuring the study, adverse events

were reported to the PTClinResNet

Administrative Core at USC, the DataManagement Center (DMC) at USC,

and the institutional review board ateach site. An adverse event was de-fined as an unexpected health-related incident that occurred duringthe course of the study, regardless ofits severity or potential relationshipto the study. Adverse events were

coded on the severity and potentialrelationship to the STEPS protocol.

Data AnalysisBecause of concern that a simplerandomization might yield notice-

able imbalance with respect totreatment assignment and baseline

walking severity, a blocked random-

ization treatment allocation proce-dure was used to ensure that 20 par-ticipants were assigned to each ofthe 4 intervention groups and thatseverity (moderate or severe walkingimpairment) was balanced withineach group (BWSTT/UE-EX, CYCLE/UE-EX, BWSTT/CYCLE, and BWSTT/LE-EX). Allocation sequence was

generated and intervention group as-signed after baseline assessments bythe DMC.

The primary outcome measure forthe preplanned hypotheses (hypoth-esis 1: BWSTT/UE-EX versus CYCLE/UE-EX; hypothesis 2: BWSTT/UE-EX

versus BWSTT/CYCLE versus

BWSTT/LE-EX) was 10-m self-selected walking speed. Due to thenature of this phase II study, in

which we were interested in thedose-response between interventioneffects and long-term functional ef-fects of our interventions, we de-cided to complete the analysis on theevaluable participants (ie, those par-

ticipants who received the full doseof therapy). However, we also reportthe results of the more conservativeintention-to-treat analysis of all ran-domized subjects using a carry-forward method by imputing the last

Endorphin Corp, 6901 90th Ave, NorthPinellas Park, FL 33782.

Cardiovascular guidelines established forthis trial were developed prior to the 2004

American Heart Association scientific state-ment on exercise guidelines for people whohad survived a stroke.65 Based on this morerecent evidence, we would recommend a sub-maximal training heart rate of 70% of age-predicted maximum heart rate when an exer-cise tolerance test has not been done in anindividual after stroke.




8/23

collected value for the posttreatmentvalue for the primary outcome mea-sure. Consistent with our prespeci-

fied analytic plan, an intent-to-treatanalysis was completed between:

(1) BWSTT/UE-EX and CYCLE/UE-EX (40 randomized participants)and (2) BWSTT/UE-EX, BWSTT/CYCLE, and BWSTT/LE-EX (60 ran-domized participants) for the pri-mary outcome measure and second-ary walking outcome measures.

Secondary outcome measures were10-m fast walking speed and6-minute walking distance. In addi-tion, paretic and nonparetic exten-sor and flexor composite torquescores (ie, the sum of the 3 extensor

torque values and the sum of the 3flexor torque values) were used tocharacterize strength gains as a result

of the interventions.

Power calculations were conductedfor the expected posttreatmentchange (postsession 24 value baseline value) in the primary out-come measure for each of the 2 pre-planned hypotheses. For hypothesis1, with a sample size of 18 in each

of the 2 groups, a one-way analysisof variance (ANOVA) will have 80%power to detect a between-group ef-fect size of 0.23 at the .05 level ofsignificance. For hypothesis 2, whenthe sample size in each of the 3groups is 18, a one-way ANOVA willhave 80% power to detect abetween-group effect size of 0.19 at

the .05 level of significance. With anexpected attrition rate of 10%, ourrecruitment goal was 80 partici-pants, with an expectation that 72participants (n18 per group) withboth baseline and posttreatmentmeasures of comfortable walkingspeed would provide enough powerto detect significant group differ-

ences for each of the hypotheses.Because our preplanned analyticstrategy (see below) was to adjust forthe severity level (moderate, severe)using an analysis of covariance(ANCOVA), in theory, our power to

detect these effect sizes is largerthan 80%.

Demographics, stroke history, andbaseline functional assessments were

compared across the 4 randomizedgroups using an ANOVA for compari-son of means and chi-square andFisher exact tests for comparison ofproportions. Variables found to be sta-tistically significant were used as co-

variates in the subsequent intention-to-

treat analyses.

For hypothesis 1, one-way ANCOVA was used to compare the postinter-vention change in primary and sec-

ondary outcomes between theBWSTT/UE-EX and CYCLE/UE-EX in-tervention groups. Severity (moder-ate, severe) was the preplanned co-

variate. Paired t tests also wereconducted within each of the inter-

vention groups to evaluate changesafter 24 sessions. Effect sizes werecalculated as the between-treatmentdifference in mean change scores di-

vided by the pooled standard devia-tion. Similar analyses were con-ducted to evaluate the persistence of

the treatment effects at 6 months. Inthis case, the dependent variable

was the 6-month change in the pri-mary and secondary walking out-come measures (6-month follow-up

value postsession 24 value).

For the primary outcome measure, a2-way repeated-measures ANOVAmodel was used to determine theinteraction effects of group (BWSTT/UE-EX, CYCLE/UE-EX) and time

(baseline, after 12 sessions, after 24sessions, and after 6 months), withtime as the repeated measure.

For hypothesis 2, similar analyses

were conducted to compare out-comes among the BWSTT/UE-EX,BWSTT/CYCLE, and BWSTT/LE-EXintervention groups. When signifi-cant differences across the 3 inter-

vention groups were found, multiple

comparisons were conducted usingthe Tukey adjustment procedure.

Similar analyses were conducted forthe extensor and flexor composite

torque scores. However, due to non-normality, the Wilcoxon rank-sumand Kruskal-Wallis nonparametrictests were used to evaluate the treat-ment effect of BWSTT/UE-EX versusCYCLE/UE-EX after 24 sessions andthe effects across all 3 BWSTT

groups, respectively. The Wilcoxonsigned-rank test was used to com-pare within-treatment differences inthe torque measurements. Statisticalanalyses were conducted using SAS,

version 9,# at the .05 level of

significance.

ResultsRecruitment and RetentionTo achieve the planned sample sizeof 72 participants (18 per inter-

vention group), a total of 284 indi-

viduals were screened by telephoneor chart review. Of these individuals,127 were evaluated for an in-person,physical screening examination (Fig. 1).

A total of 80 participants (28%) were

recruited and randomly assigned tothe 4 exercise pairs between June2002 and April 2005. Of the 204 par-ticipants who were not recruited, 173

(85%) did not meet the inclusion cri-teria, and 31 (15%) declined due topersonal reasons. Table 1 summarizesthe reasons for exclusion by clinicalsite.

Of the 80 randomized participants,71 (89%) completed the full exerciseprotocol (Fig. 1). Reasons for drop-

ping out during the interventionphase included abnormal cardiacresponse to exercise, musculoskele-tal injury, medical illness, and per-sonal reasons. Of the 71 participantsfrom the intervention phase, 63(89%) were evaluated at the 6-monthfollow-up examination. Reasons for

# SAS Institute Inc, PO Box 8000, Cary, NC27513.




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loss to follow-up included personalreasons and inability to locate theparticipant. Chi-square analysis re-

vealed that participant follow-uprates (BWSTT/UE-EX group0.95,

CYCLE/UE-EX group0.70, BWSTT/CYCLE group0.80, and BWSTT/LE-EX group0.70) were not sig-nificantly different across the 4intervention groups (P.17).

Table 2 summarizes the demo-graphic and clinical characteristicsfor the 80 randomized participantsby treatment assignment. No signifi-cant differences in baseline charac-

teristics were found across the intervention groups. Overall, 45 (56%)of the participants were men. TheaverageSD (range) age and time af-ter stroke were 60.912.4 (32.083.2) years and 25.016.2 (4.3

60.7) months, respectively. Strokecharacteristics included 42 left CVAand 38 right CVA. Stroke type in-cluded 48 infarcts, 17 hemorrhages,and 15 not specified because these

strokes were determined by clinicalpresentation. Baseline clinical out-comes, including the primary andsecondary walking outcomes, strokeimpairment severity (LE-FM motorscore, Berg Balance Scale score), and

Summary of ineligbility(n=204)

Personal reasons(n=31)

Did not meet inclusioncriteria(n=173)

STEPS Prescreened-Telephone screen (n=284)

Eligible for in-person physical screen (n=127)

Randomized (n=80)Randomized proportionally

byinitial gait speed to 1 of

4 treatment groups

Allocated toBWSTT/UE-EX group

(n=20)10 moderate10 severe

Allocated toCYCLE/UE-EX group

(n=20)12 moderate

8 severe

Allocated toBWSTT/CYCLE group

(n=20)11 moderate

9 severe

Allocated toBWSTT/LE-EX group

(n=20)10 moderate

10 severeRandomized

6-m

o

Follow

-up

Evaluable

Withdrawn by

(n=0)

Refused (n=0)

Analyzed (n=19)

10 moderate9 severe

Enrollment

administration

Withdrawn by

(n=1)Refused (n=0)

Analyzed (n=19)

10 moderate9 severe

administrationWithdrawn by

(n=2)Refused (n=0)

Analyzed (n=18)

10 moderate8 severe


(n=1)Refused (n=1)

Analyzed (n=18)

10 moderate8 severe


(n=4)Refused (n=0)

Analyzed (n=16)

9 moderate7 severe

administration

Withdrawn by

(n=1)Refused (n=3)

Analyzed (n=14)

8 moderate6 severe

administration

Withdrawn by

(n=0)

Refused (n=2)

Analyzed (n=16)

9 moderate7 severe


(n=0)Refused (n=2)

Analyzed (n=14)

9 moderate5 severe

administration

Figure 1.CONSORT diagram. Flow of participants through trial. STEPSStrength Training Effectiveness Post-Stroke study, BWSTT/UE-EXcombined body-weightsupported treadmill training and upper-extremity ergometry intervention group, CYCLE/UE-EXcombined resistive leg cycling and upper-extremity ergometry intervention group, BWSTT/CYCLEcombined body-weightsupported treadmill training and resistive leg cycling intervention group, BWSTT/LE-EXcombined body-weightsupported tread-mill training and lower-extremity progressive-resistive exercise intervention group.




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quality-of-life (SF-36 physical healthand mental health scores, SIS-16

score) variables, are presented in Ta-ble 2 by treatment assignment. Nosignificant differences were foundacross the intervention groups.

Comparison by severity level (datanot shown) revealed that, as ex-pected, the moderate group hadhigher values compared with the se-

vere group for all of the primaryand secondary outcome measures(self-selected overground walkingspeed: 0.710.20 m/s versus 0.250.12 m/s, fast walking speed:1.000.30 m/s versus 0.340.18m/s, and distance walked in 6 min-utes: 258.0786.71 m versus 93.9460.52 m), LE-FM scores (26.143.45

versus 20.895.46), and Berg Bal-ance Scale scores (49.617.26 versus33.9410.20). All differences werestatistically significant at P.0001.Stratification by severity was equiva-lent between all groups at baseline, asindicated by no significant differencesin severity by group for all variables(P.05).

Adverse Events andProtocol Variations

Across the intervention and 6 monthfollow-up period, there were 21 cu-mulative adverse events reported

that occurred in 18 participants.There were 17 adverse events during

the intervention period, 8 of which were not study related (4 falls inhome, 1 report of low back pain, 1controlled seizure, 1 participantdiagnosed with colon cancer, 1 par-ticipant diagnosed with congestiveheart failure after randomization butprior to starting intervention). Study-related events associated with the

following intervention pairs includ-ed: (1) in the BWSTT/UE-EX group,minor hand abrasion and foot pain;(2) in the BWSTT/CYCLE group, footpain, reduced blood pressure, andincreased blood pressure (twice in 1participant); and (3) in the BWSTT/LE-EX group, gluteus medius musclepain and toe pain, with later diag-

nosis of toe stress fracture (2 oc-currences in 1 participant). Fourparticipants were withdrawn fromthe study by the administration dueto the adverse events. Two adverseeffects were adjudicated as related tothe study (foot pain, toe stress frac-ture), and 2 adverse effects wereconsidered not related to study but

due to cardiac conditions (conges-tive heart failure, high blood pres-sure not responsive to medication).The participant with colon cancer

withdrew from the study.

In addition to participant adverseevents, there were 11 instances of

unanticipated protocol variations. Acommittee of PTClinResNet andSTEPS investigators assessed eachunanticipated protocol variation todetermine whether the participantshould be included in the evaluabledata set. The investigators deter-mined that 8 were minor variations,and 3 were major variations. Minor

variations included missing one ses-sion of exercise (for a reduced totalof 23 out of 24 exercise sessions) andcompleting a total of 24 exercise ses-sions but not an equal number ofeach of the 2 exercises (eg, 11 ses-sions of one exercise and 13 sessionsof the other exercise). Major varia-tions were protocol deviations that

were beyond the tolerances deter-mined a priori, such as prolongedabsences and doubling of exerciseson single days. Data for participants

with major protocol variations wereincluded in the baseline analysis but

were excluded from the final evalu-able data analysis. Of the 71 evalu-able participants, 8 were lost to the

6-month follow-up (1 died, 1 had sus-tained a myocardial infarction, and 6refused to attend or could not belocated).

Table 1.Summary of Ineligibility by Site: Strength Training Effectiveness Post-Stroke (STEPS) Study Recruitment Efforts Summary, June2002 to April 2005, Composite Across Sitesa

Reason Code

Site TF SS TL TG MS OP OR SI CS TP MP CP Total

Contacts

STEPS

Subjects

USC 4 5 5 2 2 12 3 0 2 2 4 2 78 35

RLANRC 3 0 1 1 1 11 5 0 1 0 1 0 42 18

NWU 75 2 3 12 0 8 2 6 0 20 0 9 164 27

Total 82 7 9 15 3 31 10 6 3 22 5 11 284 80

a TFtoo far poststroke (5 y); SSsecond/multiple strokes; TLtoo low on ambulation criteria; TGfree walking speed exceeded 1.0 m/s; MSmentalstatus (Mini-Mental State Exam score 24); OPother problems (participant did not show or return telephone call, personal reasons for not participating,no reason for not participating, not able to participate 34 times per week); ORorthopedic limitations (hip, knee, or ankle contracture; prior hip or kneereplacement; leg-length discrepancy 5 cm; or premorbid gait disorder); SIspasticity issues (receiving intrathecal baclofen, botulinum toxin injectionwithin past 4 mo to affected lower extremity); CScerebellar stroke; TPtransportation problems; MPmedical problems (diagnosis other than stroke, othermedical issues); CPcurrent participation in formal physical therapy program/clinical program or past participation in body-weightsupported training for4 weeks; USCUniversity of Southern California; RLANRCRancho Los Amigos National Rehabilitation Center; NUNorthwestern University.




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Table 2.Baseline Demographics, Stroke History, Primary Outcomes, and Participation Measures by Intervention Group (N80)a

BWSTT/UE-EX(n20)

CYCLE/UE-EX(n20)

BWSTT/CYCLE(n20)

BWSTT/LE-EX(n20)

Pb

Demographics

Sex: male 10 (50%) 11 (55%) 13 (65%) 11 (55%) .81

Age (y) 60.6 (13.7) 63.4 (8.6) 58.2 (15.2) 61.4 (11.2) .63

Race/ethnicity

Hispanic or Latino 2 (10%) 1 (5%) 2 (10%) 2 (10%) .92

African American 6 (30%) 6 (30%) 2 (10%) 4 (20%) .77

Asian 2 (10%) 4 (20%) 4 (20%) 2 (10%)

White 12 (60%) 9 (45%) 13 (65%) 13 (65%)

Undeclared 0 (0%) 1 (5%) 1 (5%) 1 (5%)

Education level

College: graduate 3 (15%) 10 (50%) 9 (45%) 9 (45%) .13

College: postgraduate 6 (30%) 3 (15%) 4 (20%) 4 (20%)

High school or less 11 (55%) 7 (35%) 7 (35%) 7 (35%)

Stroke characteristics

Time since stroke (mo) 27.5 (16.1) 28.4 (19.0) 23.1 (15.0) 20.7 (14.4) .40

Right-sided weakness 12 (60%) 10 (50%) 11 (55%) 9 (45%) .80

Right-hand dominance 19 (95%) 17 (85%) 19 (95%) 19 (95%) .54

Type of stroke

Hemorrhage 4 (20%) 4 (20%) 4 (20%) 5 (25%) 1.00

Infarct 12 (60%) 12 (60%) 13 (65%) 11 (55%)

Clinical criteria 4 (20%) 4 (20%) 3 (15%) 4 (20%)

Stroke severity

LE-FM motor score

(maximum score34)

24.5 (5.5) 24.4 (4.5) 24.2 (4.0) 22.1 (6.3) .49

Berg Balance Scale

(maximum score56)

42.1 (9.8) 42.6 (11.4) 45.2 (10.1) 40.4 (15.0) .72

Primary and secondary

outcomes at baseline

Comfortable gait speed (m/s) 0.49 (0.24) 0.48 (0.28) 0.53 (0.28) 0.52 (0.35) .93

Fast gait speed (m/s) 0.69 (0.38) 0.65 (0.42) 0.71 (0.38) 0.76 (0.50) .88

6-min walk distance (m) 189.3 (99.9) 170.0 (115.2) 187.6 (99.9) 190.0 (135.4) .93

Participation measures

SF-36 (n14) (n16) (n13) (n16)

Physical health 39.3 (9.0) 41.9 (5.8) 41.5 (9.0) 37.4 (8.1) .38

Mental health 52.3 (8.9) 55.4 (9.7) 49.9 (13.0) 55.7 (9.7) .40

Stroke Impact Scale (n19) (n20) (n18) (n19)

SIS-16 73.8 (14.0) 79.5 (10.9) 76.2 (13.0) 76.3 (14.7) .60

aValues are meanSD for continuous variables, frequency (%) for categorical variables. BWSTT/UE-EXcombined body-weightsupported treadmill trainingand upper-extremity ergometry intervention group, CYCLE/UE-EXcombined resistive leg cycling and upper-extremity ergometry intervention group,BWSTT/CYCLEcombined body-weightsupported treadmill training and resistive leg cycling intervention group, BWSTT/LE-EXcombined body-weightsupported treadmill training and lower-extremity progressive-resistive exercise intervention group, LE-FMlower-extremity Fugl-Meyer motor score,SF-36Medical Outcomes Study 36-Item Short-Form Health Survey, SIS-1616-item Stroke Impact Scale.b Chi-square test for categorical variables, one-way analysis of variance for continuous variables.




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Posttreatment and 6-MonthFollow-up OutcomesIn order to avoid bias in the primaryanalyses or initial interpretations, the

principal investigators (KJS, DAB,SM) were blinded to group assign-ment until the final primary analyses

were completed for the primary andsecondary walking outcome mea-sures for both the BWSTT/UE-EX andCYCLE/UE-EX comparisons and theBWSTT/UE-EX, BWSTT/CYCLE, andBWSTT/LE-EX comparisons. Table 3

presents the means and standard de-viations for each of the walking out-come measures at baseline and forsession 24 as well as pretest-posttestchange scores by experimental inter-

vention group. Table 4 presents the

means and standard deviations foreach of the walking outcome mea-sures for session 24 and the 6-monthfollow-up as well as the change

scores calculated from the posttreat-ment measurement to 6-monthfollow-up for each interventiongroup.

BWSTT/UE-EX compared withCYCLE/UE-EX. Self-selected andfast walking speeds and walkingdistance increased significantly after

the BWSTT/UE-EX intervention. Incontrast, the CYCLE/UE-EX interven-tion resulted in improvements in

walking distance but not in self-selected or fast walking speed.Paired t-test values for each within-

group comparison are provided inTable 3.

Group analysis confirmed that the

BWSTT/UE-EX intervention in-creased self-selected and fast walkingspeeds to a significantly greater ex-tent than the CYCLE/UE-EX interven-tion. The ANCOVA with walking se-

verity as the covariate revealedsignificantly greater increases in self-selected walking speed (P.004, ef-fect size0.99) and fast walking

speed (P.03, effect size0.68) forthe BWSTT/UE-EX group compared

with the CYCLE/UE-EX group. Treat-ment group differences were nonsig-nificant for the 6-minute walk test(P.50, effect size0.21). Figure 2

Table 3.Primary and Secondary Gait Outcomes at Baseline, After 24 Treatment Sessions, and Change From Baseline by Groupa

BWSTT/UE-EX(n19)

CYCLE/UE-EX(n18)

BWSTT/CYCLE(n18)

BWSTT/LE-EX(n16)

Pb

Pc

10-m comfortablegait speed

(m/s)

Baseline 0.50 (0.23) 0.43 (0.25) 0.54 (0.28) 0.57 (0.35)

Postintervention 0.63 (0.32) 0.44 (0.26) 0.63 (0.33) 0.67 (0.37)

Changed 0.13 (0.14) 0.01 (0.07) 0.09 (0.12) 0.10 (0.07) .004 .70

P .001* .67 .004* .0001*

10-m fast gait

speed (m/s)

Baseline 0.71 (0.37) 0.57 (0.36) 0.73 (0.39) 0.80 (0.51)


Change 0.10 (0.14) 0.01 (0.09) 0.08 (0.13) 0.10 (0.08) .03 .81

P .008* .79 .032* .0002*

6-min walk

distance (m)

Baseline 196.96 (96.4) 149.00 (99.6) 192.33 (102.3) 199.28 (137.87)


Change 22.5 (34.8) 15.5 (31.0) 25.5 (37.6) 45.3 (33.5) .50 .17

P .011* .049* .011* .0001*

aValues are meanSD. BWSTT/UE-EXcombined body-weightsupported treadmill training and upper-extremity ergometry intervention group, CYCLE/UE-EXcombined resistive leg cycling and upper-extremity ergometry intervention group, BWSTT/CYCLEcombined body-weightsupported treadmill trainingand resistive leg cycling intervention group, BWSTT/LE-EXcombined body-weightsupported treadmill training and lower-extremity progressive-resistiveexercise intervention group. *P.05 for baseline-postintervention comparison using paired t test.b

Pvalue is comparison of BWSTT/UE-EX and CYCLE/UE-EX data using analysis of covariance (covariateseverity).c Pvalue is comparison of BWSTT/UE-EX, BWSTT/CYCLE, and BWSTT/LE-EX data using analysis of covariance (covariateseverity).d Postintervention change calculated by subtracting baseline value from postsession 24 value.




13/23

shows the postsession 24 base-line change scores for self-selectedand fast walking speeds and distance

walked for the BWSTT/UE-EX and

CYCLE/UE-EX groups. Group differ-ences were the same when the moreconservative intention-to-treat analy-sis of all 40 randomized subjects us-ing the carry-forward method wasused for the primary outcome mea-sure (P.01).

At the 6-month follow-up, gains in

walking speed and distance walkedfor the BWSTT/UE-EX group and indistance walked for the CYCLE/UE-EX group were maintained (Tab. 4,

within-group comparisons). Addition-ally, the lack of change in walking

speed from the posttreatment mea-surement to the 6-month follow-up inthe CYCLE/UE-EX group adds validityto intervention effects rather than

other factors such as natural recoveryor individual experience. Groupdifferences after treatment persistedfor all walking outcome measures at6 months (Tab. 4, between-groupcomparisons).

To better understand changes overthe course of treatment (ie, effects

of treatment duration) and for the6-month follow-up, a 2-way repeated-measures ANOVA (with group asthe between factor and session as the

within factor) was conducted for theparticipants who completed all treat-

ment sessions (baseline, postsession12, and postsession 24 measures) andthe 6-month follow-up measure. Datafor 33 participants (19 in the BWSTT/

UE-EX group, 14 in the CYCLE/UE-EXgroup) were included in this analysis.Figure 3 illustrates the longitudinal pat-tern of change for the primary out-come measure across the baseline,postsession 12, postsession 24, and6-month follow-up measures. For self-selected walking speed, the repeated-measures ANOVA revealed significant

main effects of group (P.03) andtime (P.004) and a significantgroup time interaction (P.002).Multiple comparisons (using theTukey method) revealed that theBWSTT/UE-EX group improved self-

Table 4.Primary and Secondary Gait Outcomes Change Scores From PostSession 24 Assessment to 6-Month Follow-up Assessment(n63)a

BWSTT/UE-EX(n19)

CYCLE/UE-EX(n14)

BWSTT/CYCLE(n16)

BWSTT/LE-EX(n14)

Pb

Pc

10-m comfortable

speed (m/s)

Postsession 24 0.63 (0.32) 0.44 (0.28) 0.63 (0.35) 0.72 (0.36)

6-mo follow-up 0.65 (0.33) 0.43 (0.26) 0.64 (0.32) 0.77 (0.03)

Changed 0.02 (0.11) 0.01 (0.11) 0.01 (0.10) 0.05 (0.09) .35 .53

P .38 .61 .68 .06

10-m fast gait

speed (m/s)

Postsession 24 0.81 (0.43) 0.61 (0.42) 0.81 (0.47) 0.98 (0.49)

6-mo follow-up 0.82 (0.44) 0.60 (0.42) 0.83 (0.43) 0.94 (0.69)

Change 0.01 (0.10) 0.01 (0.17) 0.02 (0.12) 0.04 (0.37) .57 .65

P .52 .76 .54 .70

6-min walk

distance (m)

Postsession 24 219.46 (105.95) 170.52 (122.80) 221.58 (128.53) 265.69 (141.87)

6-mo follow-up 219.50 (116.85) 165.54 (116.13) 233.61 (131.31) 266.40 (133.03)

Change 0.04 (55.54) 4.98 (55.40) 12.03 (24.70) 0.71 (32.64) .81 .65

P 1.00 .74 .07 .94

aValues are meanSD. BWSTT/UE-EXcombined body-weightsupported treadmill training and upper-extremity ergometry intervention group, CYCLE/UE-EXcombined resistive leg cycling and upper-extremity ergometry intervention group, BWSTT/CYCLEcombined body-weightsupported treadmill trainingand resistive leg cycling intervention group, BWSTT/LE-EXcombined body-weightsupported treadmill training and lower-extremity progressive-resistiveexercise intervention group. *P.05 for baseline-postintervention comparison using paired t test.b

Pvalue is comparison of BWSTT/UE-EX and CYCLE/UE-EX data using analysis of covariance (covariateseverity).c Pvalue is comparison of BWSTT/UE-EX, BWSTT/CYCLE, and BWSTT/LE-EX data using analysis of covariance (covariateseverity).c Six-month follow-up change calculated by subtracting postsession 24 value from 6-mo follow-up value.




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selected walking speed significantlymore than the CYCLE/UE-EX group bysession 24 (P.01) and sustained this

improvement 6 months later (P.02).

BWSTT combined with strength-ening regimens. Consistent withthe BWSTT/UE-EX intervention, theBWSTT/CYCLE and BWSTT/LE-EXinterventions resulted in significantincreases in self-selected and fast

walking speeds and walking distance

(Tab. 3, within-group comparisons).Group analysis of the 3 BWSTT train-ing interventions revealed that theaddition of an LE strengthening pro-tocol on alternate days to task-specific training did not result in ad-

ditional gains in walking-relatedoutcomes, including walking speedor walking distance. An ANCOVA

with walking speed severity as thecovariate comparing the BWSTT/UE-EX, BWSTT/CYCLE, and BWSTT/LE-EX groups revealed no significantgroup differences for any of the

walking outcomes (Tab. 3, between-group comparisons). Figure 2 showsthe change scores for self-selectedand fast walking speeds and distance

walked for the BWSTT/UE-EX,BWSTT/CYCLE, and BWSTT/LE-EXgroups. Group differences were thesame when the more conservativeintention-to-treat analysis of data forall 60 subjects randomly assigned tothe 3 BWSTT groups using the carry-forward method was used for theprimary outcome measure (P.43).

Table 4 summarizes the long-termbeneficial effects of BWSTT on walk-ing improvements. At 6 months,

walking improvements were sus-tained regardless of whether the sub-

jects were trained in the BWSTT/UE-EX, BWSTT/CYCLE, or BWSTT/LE-EX protocol, as demonstrated by

nonsignificant differences in thechange scores between the postses-sion 24 and 6-month follow-up mea-sures (Tab. 4, within-group compar-isons). An ANCOVA comparing the 3groups that received BWSTT re-

A

Self-selectedWalkingSpeed(m/s)

FastWalkingSpeed

(m/s)

6-m

inWalkDistance(m)

BWSTT/ BWSTT/ BWSTT/CYCLE/

CYCLEUE-EX UE-EX LE-EX

ns

ns

ns

ns

0.15

0.10

0.05

0.15

0.10

0.10

50

40

30

20

10

B

C

Figure 2.Bar graphs of change (postsession 24 baseline) by group (combined body-weight

supported treadmill trainingand upper-extremity ergometry [BWSTT/UE-EX], solid bluebars; combined resistive leg cycling and upper-extremity ergometry [CYCLE/UE-EX],white bars; combined body-weightsupported treadmill training and resistive leg cy-cling [BWSTT/CYCLE], lined bars; combined body-weightsupported treadmill trainingand lower-extremity progressive-resistive exercise [BWSTT/LE-EX], hatched bars) for theprimary and secondary walking outcomes (meanSEM): (A) self-selected walkingspeed, (B) fast walking speed, and (C) 6-min walk distance. Significant baseline topostintervention changes (paired ttest, P.05) indicated by asterisk above bar. Analysisof covariance (ANCOVA) for between-group differences for BWSTT/UE-EX and CYCLE/UE-EX comparisons indicated by lower horizontal bar; ANCOVA group differences forBWSTT/UE-EX, BWSTT/CYCLE, and BWSTT/LE-EX comparisons indicated by top hori-zontal bar; significant group difference (P.05) indicated by asterisk above lowerhorizontal bar; nsnot significant.




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vealed that there were no group dif-ferences in 6-month follow-upchange scores (Tab. 4, between-group comparisons). This analysisconfirmed that, for all of the BWSTT

groups, posttreatment walking gainspersisted at 6 months.

Changes in isometric torque mea-surements. Composite torquesfor the extensors (sum of hip exten-sor, knee extensor, and plantar-flexor measurements) and flexors(sum of hip flexor, knee flexor, and

dorsiflexor measurements) were cal-culated for the nonparetic and pa-retic LEs. Medians (1 interquartilerange) for each group are shown inTable 5. In the BWSTT/UE-EX group,there was a significant increase inpostintervention torque for the non-paretic extensors (P.004) and theparetic flexors (P.02). Although

not statistically significant, the in-crease in postintervention torque forthe paretic extensors approachedsignificance (P.06). For theCYCLE/UE-EX group, there was a sig-nificant increase in postintervention

torque for the paretic flexors(P.01). There were no significantpostintervention increases instrength for either the BWSTT/CYCLE or BWSTT/LE-EX interven-

tion (Tab. 5).

Group analysis revealed no significantgroup differences in composite torquechanges between the BWSTT/UE-EXand CYCLE/UE-EX groups (Mann-

WhitneyUand Wilcoxon tests, P.05for all composite torque comparisons,Tab. 5). Similarly, group differences

were not significant for the BWSTT/UE-EX, BWSTT/CYCLE, and BWSTT/LE-EX groups (Kruskal-Wallis test,

P.05 for all composite torque com-parisons, Tab. 5).

DiscussionThe major finding of this study wasthat task-specific training using tread-

mill walking with BWS was more ef-fective in increasing walking speedthan a less task-specific, resisted cy-cling training program in individuals

with chronic stroke who have lim-ited community ambulation ability.

Endurance improvements were evi-dent for both the BWSTT-trained andresisted cyclingtrained groups. Fur-

thermore, our findings indicate thata moderate-intensity program of LE

progressive-resistive exercise alter-nated daily with task-specific train-ing did not provide an added benefitto walking outcomes after stroke. Re-gardless of whether treadmill train-ing with BWS was combined withresistive LE exercise, an intense,

task-specific walking program re-sulted in improvements in walkingspeed and endurance that were sus-tained at the 6-month follow-up.

Specificity and Intensity of

TrainingThe primary finding from the STEPStrial, that treadmill training with

BWS was more effective than re-sisted cycling in improving walkingspeed after stroke, may be ex-plained, in part, by considering thecombination ofspecificity of trainingintrinsic to walking on a treadmilland intensity of walking at challeng-ing speeds. Several recent systematicreviews of physical therapy interven-

tions have concluded that there isstrong evidence that task-specificgait training can improve poststroke

walking outcomes.33,45,46 Treadmilltraining with BWS at challengingspeeds is a primary example of ahigh-intensity, task-specific gait train-ing intervention because it requiresthe participant to engage in repeti-

tive walking practice with high de-mand during the training session.Consistently, long-term changes inperformance are achieved when theconditions of task practice are simi-lar to the task and conditions in

which retention or transfer perfor-mance is expected.66 In addition,task specificity effects are particu-

larly strong for highly practicedskills, where motor abilities acquired

with practice are specific to the taskthat is performed.67 Keetch et al67

demonstrated this with a highly prac-ticed skill, free-throw shooting, in

0.80

0.60

0.40

0.20

Baseline After 12 Sessions After 24 Sessions 6-mo Follow-up

Self-selectedWalking

Speed(m/s)

Figure 3.Time series plot comparing combined body-weightsupported treadmill training andupper-extremity ergometry (BWSTT/UE-EX) () and combined resistive leg cycling andupper-extremity ergometry [CYCLE/UE-EX] () group means (SEM) at baseline, after12 sessions, after 24 sessions, and at 6-month follow-up for the primary outcome ofself-selected walking speed.




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expert basketball players. It is con-ceivable that highly practiced func-tional tasks such as walking also areinfluenced by similar task specificityeffects.

For individuals after stroke, walkingis a highly practiced functional task

where the learner has to reacquirethe motor abilities associated withgait function. In this study, all of theprotocols that incorporated BWSTT

were effective in improving immedi-ate and long-term walking ability.Moreover, this ability transferred

from the treadmill training environ-ment to overground walking. In con-trast, there was evidence that re-sisted cycling, which required theparticipants to coordinate a lower-limb cycling pattern with an LE ex-

tensor load, resulted in improve-ments in endurance but not in gaitspeed. Although it has been demon-strated that cycling with or withoutlimb loading requires kinematic pat-terns and coordinated muscle activa-

tion patterns similar to those re-quired for walking,6870 it appearsthat the specificity effects of thistype of training affected distance

walked but not speed in individuals with chronic stroke. This partial ef-fect may be due to the nature of theCYCLE protocol used in this study,

which involved 20 repetitions that

were repeated for 10 sets per ses-sion. This type of training stimulusmay be more effective in improvingendurance that benefited walkingdistance versus walking speed.

We argue that the standardized inter-vention protocol for BWSTT used inthe STEPS trial incorporated suffi-cient training specificity, intensity,and duration to achieve a significantchange in walking speed in individ-

uals with chronic stroke that wasmaintained at the 6-month follow-up. There were improvements in

walking speed and walking distanceacross all 3 groups whose interven-tion incorporated BWSTT. The func-tional walking classification devel-oped by Perry and colleagues2 is auseful way to determine whether

changes in walking speed are associ-ated with clinically meaningfulchanges in walking outcomes at thelevel of participation (ie, communityambulation). Of the 53 participants

who received an intervention that

Table 5.Composite Flexor and Extensor Torques (in Newton-Meters) for the Paretic and Nonparetic Lower Extremities at Baseline andPostintervention Change (Median, Range) by Group (n69)a

BWSTT/UE-EX(n19)

CYCLE/UE-EX(n18)

BWSTT/CYCLE(n18)

BWSTT/LE-EX(n16)

Pb

Pc

Flexors, nonparetic

Baseline 39.70 (30.9350.23) 42.12 (33.2353.47) 47.90 (38.6362.73) 47.10 (32.2056.73)

Changed 0.70 (2.907.10) 0.21 (3.672.37) 0.47 ( 6.936.17) 0.10 ( 3.773.50) .92 .72

P 1.00 .81 1.00 1.00

Flexors, paretic

Baseline 20.97 (10.2732.07) 23.63 (13.9332.13) 29.13 (14.6733.30) 28.13 (20.6334.50)

Change 3.43 (1.537.63) 1.53 (0.577.33) 0.70 ( 2.333.10) 1.60 (4.274.70) .28 .07

P .02* .01* .63 .61

Extensors, nonparetic

Baseline 87.97 (54.30119.67) 96.97 (79.03109.70) 95.30 (74.40137.07) 107.93 (87.63146.13)Change 9.17 (1.8716.47) 1.48 ( 11.8315.53) 0.20 (6.6716.23) 5.83 ( 14.3711.10) .07 .16

P .004* .81 1.00 1.00

Extensors, paretic

Baseline 49.87 (36.1767.10) 56.07 (35.0782.47) 64.93 (47.6083.67) 64.80 (49.4391.13)

Change 9.10 ( 1.1718.30) 3.02 (8.8016.83) 2.10 (2.7011.43) 7.67 ( 15.0712.43) .35 .46

P .06 .48 .33 .30

a BWSTT/UE-EXcombined body-weightsupported treadmill training and upper-extremity ergometry intervention group, CYCLE/UE-EXcombined resistiveleg cycling and upper-extremity ergometry intervention group, BWSTT/CYCLEcombined body-weightsupported treadmill training and resistive leg cyclingintervention group, BWSTT/LE-EXcombined body-weightsupported treadmill training and lower-extremity progressive-resistive exercise interventiongroup. * P.05 for baseline-postintervention comparison using the Wilcoxon signed-rank test.b Pvalue is comparison of BWSTT/UE-EX and CYCLE/UE-EX data using the Wilcoxon rank-sum test.c Pvalue is comparison of BWSTT/UE-EX, BWSTT/CYCLE, and BWSTT/LE-EX data using the Kruskal-Wallis test.d Postintervention change calculated by subtracting baseline value from postsession 24 value.




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included BWSTT, more than 50% (27out of 53) increased walking speedto an extent that would classify them

at a higher functional walking levelpostintervention.

Based on an analysis of data of theparticipants who completed all 24sessions of their randomization as-signment, we found that BWSTT

with initial BWS of 30% to 40% that was reduced across sessions, and at

treadmill speeds of 1.5 to 2.2 mphfor 20 minutes of walking time (withrests, as needed), for a minimum of 2sessions over a 6-week period re-sulted in functionally significantchanges in walking outcomes in a

majority of the individuals afterstroke who participated. Findingssuch as these provide information

about an effective dosing of exerciseand gait training needed to achievefunctional poststroke walking out-comes. Additionally, it is interestingto note that an intense schedule of12 sessions of treadmill training withBWS was enough of a training stim-ulus to increase walking speed, walk-ing distance, and LE strength in indi-

viduals with chronic stroke. This wastrue when BWSTT was combined

with either the UE sham exerciseprogram or a progressive LE exerciseprogram. The robustness of this find-ing is validated further by the com-parable results of the intention-to-treat analysis for self-selected

walking speed that included all ran-

domized participants where we car-ried forward baseline or postses-sion 12 treatment data for missingpostsession 24 treatment data.

Furthermore, the repeated-measuresanalysis that compared changes in

walking speed over the course oftraining and the 6-month follow-up

(Fig. 3) suggests that the significantchange in walking speed was not ev-ident between the BWSTT/UE-EXand CYCLE/UE-EX groups until ses-sion 24 (ie, the 12th BWSTT session).These findings replicate the pilot

work by Sullivan et al35 and demon-strate that both treatment intensity(ie, treadmill training speed of 2.0

mph) and duration (ie, minimum of12 BWSTT training sessions) are fac-

tors associated with BWSTT trainingeffectiveness. This phase II RCT can-not address the optimal training du-ration (ie, effect of increased trainingsessions) or timing (ie, early or lateafter acute stroke) for this type oflocomotor training after stroke. In

order to inform clinical practice,larger-scale rehabilitation clinical tri-als that include a larger poststrokepopulation are required to addressthese factors.

Does BWS add a critical element tothe training experience? Clearly, fur-ther studies would need to be spe-

cifically designed to adequately an-swer this question. However, thefindings of a study by Visintin et al31

and a follow-up analysis of the ef-fects of stroke severity by this samegroup71would suggest that BWS dur-ing treadmill walking appears to bean active ingredient of this inter-

vention. In our experience, there are

many additional benefits of BWS provided by an overhead suspensionsystem. First, the unweighting pro-

vides added support and positive re-inforcement to the patients so thatthey are able to practice walking ina safe environment without fear offalling. Second, BWS is progressivelydecreased over the course of train-

ing, which allows the therapist toprogressively increase the biome-chanical demand (ie, body weightload to muscles) as the individual

with stroke develops improved mo-tor control and power during thestance and swing phases of gait. In-deed, one of the criteria for pro-gression is for the therapist to de-

crease stepping assistance level asthe patient increases motor control.

Third, the use of the harness and theprogressive manipulation of BWSand therapist assistance are impor-

tant therapeutic factors that result inmore intense task practice of walk-ing (ie, able to achieve faster walking

speeds despite severity level) thanwould occur on a treadmill without

BWS. Finally, the participants them-selves reported a higher level of con-fidence in their walking skills. Con-sistently, participants reported thatthey felt that they were practicingsomething meaningful and that theyenjoyed the walking sessions. Fur-

ther study of how this type of train-ing improves patient self-efficacy is

warranted. In addition, the BWSTTgroups did receive 50 ft (15 m) ofoverground walking reinforcementafter the treadmill session. Though

possible, it is unlikely that this low-intensity activity alone could haveaccounted for the strong effects of

the BWSTT group or differences be-tween the CYCLE and the BWSTTgroups.

Evidence for Overtraining EffectsContrary to our initial hypotheses,strength training added to task-specific BWSTT training did not pro-

vide an additive effect to walking

outcomes. Our results suggest thatBWSTT alternated with a UE shamexercise was more effective in in-creasing LE strength than a com-bined training program that includedboth task-specific and strength train-ing (BWSTT/CYCLE, BWSTT/LE-EX).This appears counterintuitive in apopulation of adults with stroke,

where motor control deficits are re-lated to both weakness and the tim-ing of muscle activation needed tosupport functional tasks such as

walking.72 However, evidence existsin the exercise science literature thatexercise programs for young adultsthat combine high-volume and high-intensity endurance and resistive ex-

ercise programs can reduce thestrengthening effect, particularly ifthe muscle groups recruited are usedduring both strength and endurancetraining (for reviews, see Kraemerand Ratamess73 and Hunter et al74).




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Recent investigations of the appar-ent interference of endurance train-ing on strength development have

studied older adults who werehealthy, including 55- to 75-year-old

men75

and 60- to 84-year-old menand women.76 Both studies con-trolled for frequency and durationbetween exercise groups over 20and 12 sessions of training, respec-tively. Endurance training, includingcycling or walking on a treadmill,

was in the range of 60% to 80% ofestimated heart rate reserve. Upper-extremity and LE resistance trainingon exercise machines ranged frommoderate (20-RM) to high (8-RM)intensity levels, as defined by the

American College of Sports Medicineguidelines.54 Both studies demon-strated that, in older adults, cardio-

vascular training alone resulted in LEstrength gains comparable to thoseachieved through either a low- orhigh-resistance or combined program.

The lack of a significant strength in-crease in the combined exercisegroups in our study might be ex-plained by a similar interference ef-

fect between resistance and endur-ance training. Significant increases inthe nonparetic extensors and pareticflexors as well as a nonsignificanttrend for the paretic extensors(P.06) were found in the BWSTT/UE-EX group and for the paretic flex-ors in the CYCLE/UE-EX group, butnot in the combined BWSTT/CYCLE

and BWSTT/UE-EX groups. If there was no interference from the com-bined exercise groups, we wouldhave expected the torque changes tobe similar in all 3 BWSTT groups.

One possible explanation is that wehad induced an overtraining effect inthe combined exercise groups. The

training intensities of our groups were moderately high for the BW-STT sessions, as validated by age-predicted maximum heart rates thataveraged 62%10.3% in session 1and 67%10.1% in BWSTT session

12 for our participants. For the LE-EXprotocol, loads were adjusted foreach muscle group such that the par-

ticipants completed 8 to 10 repeti-tions for 3 sets at 80% of their 10-RM

load. For the CYCLE protocol, theparticipants completed a minimumof 12 to 20 repetitions for 10 sets

with as much load as could be toler-ated. In both of the resistive exerciseconditions, the perceived effort re-ported by the participants was high.

For the exercise protocol used in thisstudy, it appears that the beststrength training stimulus for the LEoccurred in the BWSTT/UE-EXgroup, where the LE muscle groups,progressively loaded through de-

creasing BWS, were provided ade-quate rest on the alternating UE-EXsham intervention days.

Smith et al77 also reported LEstrength gains in adults with chronicstroke who participated in a tread-mill aerobic exercise program ad-ministered 3 times per week over 12

weeks. The results of their study andour study suggest that the benefit oftask-specific training, and the associ-

ated increases in torque production,could be attributed to improved mo-tor unit activation that occurs as in-dividuals after stroke actively engagein functional tasks that demand mus-cle activation that is progressedacross treatment sessions. The short-term increases in torque productionover the 6-week training program

that we observed would provide ad-ditional support for improved cen-tral activation.

Our findings need to be interpreted with caution. The STEPS protocolcombined resistive exercise and amoderately high intensity of trainingon alternate days and induced what

appeared to be an overtraining ef-fect. However, recent findings byPatten et al78 suggest that a dy-namic high-intensity resistance train-ing intervention (15 sessions over 5

weeks) followed by clinic-based

gait training (9 sessions over 3 weeks) resulted in increases in gaitspeed and torque production for a

group that received eccentric mus-cle strengthening. Together, these

studies reveal the need for furtherwork to determine the optimal doseresponse and scheduling of exerciseinterventions that combine resis-tance and task training to improvefunctional walking ability in individ-uals after stroke.

Study LimitationsThere are several limitations associ-ated with this study. We did notachieve the isometric strength gainsthat we projected with the CYCLE

protocol. One explanation is thatthe exercise repetitions selected forthis protocol were 12 to 20 repeti-

tions for 10 sets, which is more ef-fective for increasing muscle endur-ance.73 Due to physical limits of therecumbent bicycle that we used,some participants progressed to thehighest level of resistance (ie, 100lb); therefore, the only method toprogress the exercise was to in-crease repetitions. Some individuals

actually completed as many as 40repetitions per set. The increase inrepetitions rather than load likelyfurther enhanced the muscle endur-ance effect.

Another potential limitation is thatthe hemiparetic muscles were testedisometrically in isolated positions

and potential gains in torque gener-ation during full limb flexion or ex-tension synergy patterns were notmeasured by these tests. Due to lim-itations in selective movement abil-ity, this resulted in great variability inour torque data, with some differ-ences in baseline torque valuesamong groups. However, the longi-

tudinal torque comparisons wereconsistent, regardless of whetherparametric or nonparametric statis-tics were used (we used the moreconservative nonparametric compar-isons for this analysis), which sug-




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gests that a larger sample size mayhave provided more power for de-tecting group differences.

Clinical Relevance and

ConclusionsThis study investigated the effects of 4standardized training protocols to im-prove walking ability in individuals

with chronic stroke. This is the firstrehabilitation RCT to use exercisecontrol-comparison groups to report

the effects of task-specific training, re-sistance training, and protocols thatcombined these 2 forms of exerciseon measures of walking activity out-comes and strength after stroke.

The results of the present investiga-tion indicate that treadmill walking

with BWS that uses

sullivan et al 2007 steps-cr 5

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