D. Casey Kerrigan, M.D., M.S.Chairman, OESH Shoes and JKM Technologies, LLCFormer Professor and Chair, University of Virginia

Department of Physical Medicine and RehabilitationAdjunct Professor, University of Virginia Department

of Mechanical and Aerospace EngineeringFaculty, University of Virginia School of Architecture

Healthy Shoe Design: How Shoes Affect Joints

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Studies of the effects of shoes on forces and loads in the body done at Harvard Medical School and the University of Virginia

10 Camera Vicon Motion Analysis System

Marker Placement

Force Plate

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Force Plate Measurements

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Force Plates in a Treadmill

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Walking, Running, Standing

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Studied Subjects of All Ages

(This one’s now at Oxford!)

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0 10 20 30 40 50 60 70 80 90 100 -0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

High Heels Barefoot

% Gait Cycle

Coronal Knee Torque

Val

gus

V

arus

N-m

/kg

-m

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Lancet 2001;357:1097-1098

…more studies on all different types of shoes

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ABC 20/20 Feature Presentation

Women's shoes and knee osteoarthritis.Kerrigan DC, Lelas JL, Karvosky ME.Lancet. 2001 Apr 7;357(9262):1097-8.

Wide heeled shoes also increase torques

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Effect of Running Shoes on Knee Varus Torque

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And shoe components – orthotics and off the shelf arch supports

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Knee joint torques during runningArrows point to the moment of peak “impact”

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Peak torques relate to:

Illiotibial Band SyndromeGluteus Medius TendonopathyTrochanteric BursitisHip osteoarthritisPatellofemoral Knee PainMedial Knee OsteoarthritisShin SplintsTibial Stress FracturePlantar FasciitisMetatarsal Stress Fracture

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And here’s what all these injuries have in common:

The torques, forces, pressures stresses and strains that cause ALL of them occur at the same moment in the gait cycle – when the foot is firmly planted on the ground – NOT AT IMPACT

Plantar Fasciits

TibialStress Fracture

Medial Knee Osteoarthritis

MetatarsalStress Fracture

Illiotibial BandSyndrome

Shin Splints

Gluteus Medius Tendinopathy

TrochantericBursitis

PatellofemoralKnee Pain

HERE….

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N=74

Natural Springiness of the Foot During Gait

Walking

Running

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This is the moment of Impact

Note the tiny ground reaction force

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Note the large ground reactionforce

This is when the foot is firmly planted

Peak stresses occur at time of peak GRFtwice during walking

Sagittal plane walking

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Peak stresses occur at peak GRF once during running

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Sagittal plane running

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Impact

Planted

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Planted

Impact

(This one’s going to Yale next year!)

Ground Reaction Force Curve in Running

First peak The impact peakHas nothing to do

with injurySecond peak

The so called “active” peak

Has everything to do with injury

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Force(body weight)

2

1

Absorption Acceleration

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The research papers that define OESH Shoe Construction

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Shoe attributes that abnormally increase loads on jointsHeel height differential Arch supportSide to side contouring (the typical

shoe has a cradle running side to side

Cushioning which effectively produces unwanted contours during weight support -- a heel differential, arch support, side to side contouring

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What then comprises a good shoe?

Flat in the heel to toe directionFlat in the side to side directionNo arch supportNo cushioning or dampening which

causes unwanted contouringTrue responsiveness or springiness

in a perfectly flat sole that works in unison with foot compliance

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