does changing footfall patterns benefit runners?€¦ · joseph hamill, phd . professor,...

Biomechanics Laboratory

Joseph Hamill, PhD Professor, Kinesiology

Associate Dean for Research, SPHHS


University of Massachusetts Amherst, MA 01003

Does Changing Footfall Patterns Benefit Runners?

Biomechanics Laboratory Biomechanics Laboratory

Footfall Patterns - RF

2


Footfall Patterns - FF

3


Footfall Patterns - MF

4


Rearfoot v. Forefoot Runners

• of 753 runners at the 10 and 20 km point of marathon races, 81% RF, 19% MF, 0% FF

• 283 elite runners analyzed at 9.3 mile mark of a half marathon: 75% RF, 24% MF, 1 %FF

• 936 runners analyzed at 10 km point of marathon: 89% RF, 3% MF, 2% FF, 6% asymetrical

Ker et al., (1983)

Hasegawa et al., (2007)

Larsen et al., (2011)


Why are there so few forefoot runners?

• ancient homo (∼500,000 years ago) may have been a runner (Liebermann et al., 2010)

• what footfall pattern did they use when running?

• Liebermann and others suggest that they used a FF pattern

• argument for using a FF pattern suggests that since ancient homo ran with a FF pattern so........


• forward dynamics computer model two-dimensional (sagittal) 11 segments: trunk, two legs vertical trunk force ≈ arm swing soft constrains on joint ROM (ligaments, etc.) foot-ground contact wobbling masses (trunk, thighs, calfs)

Miller & Hamill, (2012)

• 12 Hill-based muscle models per leg contractile and series elastic components parameters: dynamometer experiments

Why do we have multiple footfall patterns? Why are there so few FF runners?


• RF strike pattern for minimal energy solution

• MF strike increased energy rate (15.9 → 16.9 W•kg-1,

+1.2 kcal•min-1)

• FF strike to maximize average speed

Energetic Optimality for Computer Model


Rearfoot v. Forefoot

• there is little to no evidence that FF or MF running is a healthy alternative to RF running

• there is also little scientific evidence that RF is a healthy alternative to FF or MF running


• changing to a FF or MF footfall pattern from an RF pattern:

caused by modern footwear

is metabolically more efficient

decreases the impact forces in running

reduces running-related injuries

What those who advocate change really say?


Are footwear the cause of few FF runners?

• one argument often mentioned is „modern footwear“

• the development of the modern running shoe (i.e. thick heel) allowed individuals to run with an RF pattern

• the thick heel cushioning thus decreased the number of runners who ran with a FF pattern

1971 2012 2013


University of Oregon 1977


• running with a FF pattern is not more economical than running with an RF pattern

Running Economy

0

2

4

6

8

10

12

14

16

18

RF Pattern FF Pattern

NM

R (W

/kg)

11.95 ± 0.68

12.42 ± 0.66

Gruber et al., 2012 Habitual RF Runners


Speed Group CHO (g·hr-1) CHO (% of EE)

Slow RF 88.89 ± 23.41 51.3 ± 12.7

FF 100.23 ± 21.76 58.5 ± 8.3

Medium RF 131.17 ± 39.65 64.7 ± 15.5

FF 140.08 ± 33.00 71.3 ± 11.4

Fast RF 187.87 ± 58.05 77.9 ± 16.8

FF 186.12 ± 39.82 80.9 ± 11.8

Carbohydrate Oxidation

Gruber et al., 2012

Habitual RF Runners


Lieberman et al., 2010

RF v. FF Running

18


Vertical Ground Reaction Force Component

RF FF

0 20 40 60 80 100 0

500

1000

1500

2000

Percent Support

VG

RF

Com

pone

nt (N

)

Gruber et al., 2011


-400

0

400

800

1200

1600

0 50 100 150 200 250 Time (ms)

Forc

e (N

)

passive

VGRF

active

2000

Spectral Decomposition of VGF Component


0

200

300

400

500

600

Am

plitu

de

100

0 0 5 10 15 20 25

Frequency (Hz)

Vertical Ground Reaction Force Frequencies

21

impact peak

active peak

4 – 8 Hz

10 – 20 Hz


Frequency Content of VGRF

0 5 10 15 20 25 30 0

500

1000

1500

2000

2500

Frequency (Hz)

Am

plitu

de

RF

FF

R

Gruber et al., 2011

22


Why is their no impact peak in FF running?

• in RF running, the foot/ground collision occurs early in the support period

• in FF running, the collision occurs later in the support period

RF FF

Percent Support

VG

RF

Com

pone

nt (N

)


Wavelet Analysis of VGRF Component Rearfoot Pattern Forefoot Pattern


Time (ms) Time (ms)

Forc

e (N

)

Forc

e (N

)

active peak

impact peak

Bobbert et al., 1992

The Impact Peak in RF running?


The Impact Peak in FF running?

0

500

1000

1500

2000

0 50 100 150 200

Forc

e (N

)

Time (ms)

Forc

e (N

)

0

500

1000

1500

2000

0 50 100 150 200 Time (ms)


Do Impacts Cause Injury?

• running on hard surfaces did not increase injuries over running on soft surfaces

• incidence of osteoarthritis found in equal

frequency in runners and non-runners

Van Mechelen, 1992

Lane et al., 1986; Panush et al., 1986; Eichner, 1989


Injury and Impacts?

• subjects with greater impact peaks had significantly fewer running-related injuries

Nigg, 1997

Relative Injury Frequency (%)

30

20

10

0

Maximum Impact Force (N) Low 25% Medium 50% High 25%


Do Impacts Really Cause Injury?

?????????


Injury Epidemiological Studies

• prospective study on 471 runners - no difference in injury rates between FF and RF - suggested injury site affected by portion of the foot that makes initial contact Kleindienst, 2003

• prospective study on 1203 runners - no differences in injury rates between FF and RF - difference in location and kind of injury

Walther, 2005

• few epidemiological studies


Possible Injuries If Changing to an FF Pattern

• Achilles tendinitis

• Plantar Fasciitis

• Patellofemoral Pain


Achilles Tendinitis

Gruber et al., 2011

Ach

illes

Tend

on F

orce

(N)

Percent Support

RF

FF


Plantar Fasciitis

Gruber et al., 2010

RF Segment

FF Segment

Presenter

Presentation Notes

In RF running, after the heel touches the ground, ***the RF segment begins to EV which is followed by FF EV In FF running, We believe that the RF and FF segments will ***EV at the same time b/c the foot is more rigid when in a plantar flexed position


Foot Motion with Different Running Patterns

foot acts like a rigid structure thus plantar fascia is always under tension

Presenter

Presentation Notes

In FF running, We believe that the RF and FF segments will EV at the same time b/c the foot is more rigid when in a plantar flexed position This study found that FF running involves more in-phase coordination than RF running In-phase coordination during FF running may be a result of the longitudinal arch being more rigid when the foot is plantar flexed


Patellofemoral Pain

Kleindienst et al., 2005

• increased knee abduction and external rotation moments related to PFPS (Stefanyshyn et al., 2001)



caused by modern footwear NO

is metabolically more efficient NO

decreases the impact forces in running NO

reduces running-related injuries NO (and possibly causes running-related injuries)



Conclusions

• the change in footfall pattern (i.e. rearfoot to forefoot) may result in stressing tissue not used in the RF pattern possibly resulting in a running-related injury

• our research suggests that changing one’s footfall pattern is not beneficial to the runner


Take-home Message

Changing one’s footfall pattern is not good!

thus

Variety of one’s footfall pattern is not always the spice of life!


Thank you!

Questions?

www.umass.edu/biomechanics/

does changing footfall patterns benefit runners?€¦ · joseph hamill, phd . professor,...

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