Does Changing Footfall Patterns Benefit Runners?€¦ · Joseph Hamill, PhD . Professor,...
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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?
Transcript of 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
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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
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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
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Percent Support
VG
RF
Com
pone
nt (N
)
Gruber et al., 2011
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-400
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800
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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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500
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Am
plitu
de
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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
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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?
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0 50 100 150 200
Forc
e (N
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Time (ms)
Forc
e (N
)
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1500
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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
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
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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
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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/
