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

Biomechanics Laboratory

Joseph Hamill, PhD Professor, Kinesiology

Associate Dean for Research, SPHHS

Biomechanics Laboratory

University of Massachusetts Amherst, MA 01003

Does Changing Footfall Patterns Benefit Runners?

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Footfall Patterns - RF

2

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Footfall Patterns - FF

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Footfall Patterns - MF

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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)

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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........

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• 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?

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• 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

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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

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• 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?

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• 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?

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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

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University of Oregon 1977

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• 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?

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• 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

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RF Pattern FF Pattern

NM

R (W

/kg)

11.95 ± 0.68

12.42 ± 0.66

Gruber et al., 2012 Habitual RF Runners

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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

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• 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?

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Lieberman et al., 2010

RF v. FF Running

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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

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-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

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0

200

300

400

500

600

Am

plitu

de

100

0 0 5 10 15 20 25

Frequency (Hz)

Vertical Ground Reaction Force Frequencies

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impact peak

active peak

4 – 8 Hz

10 – 20 Hz

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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

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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

)

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Wavelet Analysis of VGRF Component Rearfoot Pattern Forefoot Pattern

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Time (ms) Time (ms)

Forc

e (N

)

Forc

e (N

)

active peak

impact peak

Bobbert et al., 1992

The Impact Peak in RF running?

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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)

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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

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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%

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Do Impacts Really Cause Injury?

?????????

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• 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?

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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

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Possible Injuries If Changing to an FF Pattern

• Achilles tendinitis

• Plantar Fasciitis

• Patellofemoral Pain

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Achilles Tendinitis

Gruber et al., 2011

Ach

illes

Tend

on F

orce

(N)

Percent Support

RF

FF

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Plantar Fasciitis

Gruber et al., 2010

RF Segment

FF Segment

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Foot Motion with Different Running Patterns

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

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Patellofemoral Pain

Kleindienst et al., 2005

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

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

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)

What those who advocate change really say?

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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

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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!

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Thank you!

Questions?

www.umass.edu/biomechanics/