Dynamic Foot Function

Transcription

1 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 Disclosure belangen spreker (potentiële) belangenverstrengeling Geen 1

2 Overview and Acknowledgements Evolution of the Foot in a Split Second Foot biomechanics and pedobarography Effect of Habitual Shoe use on Foot function Role of the (sports) shoe construction Dr Kristiaan D'Août Department of Musculoskeletal Biology Institute of Ageing and Chronic Disease University of Liverpool 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 2

3 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?????) 3

4 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 Gorilla Neanderthal man Modern Man Development of Lateral Longitudinal Arch Deepening of Transverse Tarsal Arch 4

5 Functional Role of Sustentaculum Tali: 4 Inter- and Intra Racial Patterns of Articular Facets Subtalar Joint Egyptians N=300 (L/R) Africans N>500 Indians N=401 Caucasians N>500 Veddah (Ceylon) 63% 30% 4.7% 2% 60-63% 30-36% 10% <1% 67% 26% 5% 2% 33-40% 67% 12% <1%??? >50% Design of the Longitudinal Arch : 1 st ray supports Sustentaculum Tali 5

6 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

7 Neutral & First degree Pronation 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,

8 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, Effect of Habitual Footwear Use D Aout et al, Footwear Science Vol. 1, No. 2, June 2009,

9 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) 9

10 Sport Shoe construction vs. Rearfoot control Important features Heel Flare Midsole design Heel Height Sport shoe design vs. Fore & Midfoot control Last shape Important features Outsole curvature Shape cross section Outsole straight half-board curved 10

11 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 MP Asics Gel Hockey Pro Dita Attack ER Dita Xtreme SR-10W* Grays Child hockey shoe Adidas Hockey

12 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) 12