Dynamic Foot Function - NVOS

MOVEFIT
Dynamic Foot Function
Is it influenced by shoe design and insole material?
Stephan F.E. Praet, MD PhD FEBSM
Sports & exercise physician
MoveFIT-Sports Medicine
Dept. Rehabilitation Medicine
Erasmus University Medical Centre,
Rotterdam, the Netherlands
[email protected]
Disclosure belangen spreker
(potentiële) belangenverstrengeling
Geen
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Overview and Acknowledgements
Evolution of the Foot in a ‘Split Second’
Foot biomechanics and pedobarography
Effect of Habitual Shoe use on Foot function
Dr Kristiaan D'Août
Department of Musculoskeletal
Biology | Institute of Ageing
and Chronic Disease |
University of Liverpool
Role of the (sports) shoe construction
Complexity of the Foot
In order to understand foot anatomy,
we have to account for two aspects:
1. Function: foot anatomy reflects functional requirements
BUT! The foot has not been « engineered » de novo
2. Evolution: foot anatomy reflects its historical background
and may show vestigeal remains
1. A structure (in the broad sense) can change (over generations) if there is an adaptive benefit.
If there is a cost, or if there is no benefit, they are unlikely to change.
Genetic
variation
Design
variation
Performance
variation
Fitness
variation
2. Changes may lead to unwanted side effects (pleiotropic effects).
Courtesy of dr. K. Août, University of Liverpool
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Morton’s view on the Human Foot
Insights from Modern Apes
Bonobo:
upright tree climbing
Bonobo:
upright tree walking
Bonobo:
upright terrestial walking
Macaque:
Acute upright terrestial walking
(After narcosis ?????)
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Terrestial changes:
Reduced Metatarsal Torsion:
Chimpansee
Gorilla
Man
Improved Leverage Axis in Movement Direction
Terrestial changes:
Reduced Obliquity of Sustentaculum Tali:
•Body weight distribution towards lateral side
•Less Abduction of Hallux / Metatarsal I
•Development of Lateral Longitudinal Arch
•Deepening of Transverse Tarsal Arch
Gorilla
Neanderthal man
Modern Man
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Functional Role of Sustentaculum Tali:
4 Inter- and Intra Racial Patterns of Articular Facets Subtalar Joint
Egyptians
N=300 (L/R)
63%
30%
4.7%
2%
Africans
N>500
60-63%
30-36%
10%
<1%
Indians
N=401
67%
26%
5%
2%
33-40%
67%
12%
<1%
?
?
?
>50%
Caucasians
N>500
Veddah
(Ceylon)
Design of the Longitudinal ‘Arch’ :
1st ray supports Sustentaculum Tali
5
Mechanics of the Foot during
Walking and Running:
Transfer of Stress from Static ⇒ Dynamic Plane of Balance
Heel
off
Loading mechanics of MT-I
MT-I support
MT-I support
6
Neutral
Pronation
&
First degree
The « normal » human foot
Picture by dr. K. Août, University of Liverpool
Shod South Indians wear less constricting footwear than Western populations.
They remove their shoes often.
BI < SI < W
D’ Aout et al, Footwear Science Vol. 1, No. 2, June 2009, 81–94
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The « normal » human foot
#009
#014
#022
South-Indians, habitually wearing footwear (group « SI »)
#141
#150
#156
Pictures by dr. K. Août, University of Antwerp
South-Indians, habitually walking barefoot (group « BI »)
D’ Aout et al, Footwear Science Vol. 1, No. 2, June 2009, 81–94
Effect of Habitual Footwear Use
D’ Aout et al, Footwear Science Vol. 1, No. 2, June 2009, 81–94
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Tailor-made Solutions to optimize Foot balance
D3D concept (RSscan International)
How about the Shoe Design?
• Effect of lever arm and bidensity sole stiffness on
GRF and pronation velocity... (Stacoff et al., 1988; Nike, 1989)
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Sport Shoe construction vs. Rearfoot control
Important features
• Heel Flare
• Midsole design
• Heel Height
•
Sport shoe design vs. Fore & Midfoot control
Important features
•Last shape
•Outsole curvature
•Shape cross section Outsole
straight
half-board
curved
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Biomechanical Features Field Hockey shoes
courtesy Bas de Bruin, June 2011
Stability Features of Field Hockey shoes
Ratings by Bas de Bruin, June 2011
Brand /Model
Rocker
Last Curvature
Torsional Stiffness
Asics Gel Black heath 3*
+
+++++
++
Asics Gel Lethal MP3
++
+++++
+++
Asics Gel Hockey Pro
+
+++++
+
Dita Attack ER-10
++++
+++++
+++
Dita Xtreme SR-10W*
+++
+++
++++
Grays Child hockey shoe
++++
++++
+
Adidas Hockey
+++++
+++++
+++
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Additional motion control through
• Individualised shoe modifications
• Corrective orthotics
However, success rate depends highly on:
•
Choice of appropiate materials
• Critical evaluation
(eg. video or foot pressure feedback)
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