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Ch07-I044963.fm Page 30 Tuesday, August 1, 2006 12:30 PM
Ch07-I044963.fm
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4: The heel strike corresponds to the foot contacting the ground, and the force causes the ankle
plantarflexion rapidly.
5: Since the force at the time of midstance is in the neutral position of the load-cell, it is zero.
6: Heel-off occurs as the heel loses contact with ground, and the force is the maximum of the ankle
plantarflexion.
Although this is a healthy person's condition, the patient's drop-foot tendency increases the force of
ankle plantarflexion. The difficulty in walking occurs due to this drop-foot, which occasionally
causes a fall during gait.

Heel strike Midstance Heel-off Acceleration Midswing Deceleration
Stance phase Swing phase
otance pnase owmg pirns
Fig. 4: Comparison with the gait (Healthy person)
The relation between the moment and the visco-elasticity of the muscle of the circumference of the
ankle is shown. It is thought that the moment in the circumference of an ankle joint is generated by
tension in the muscles of the foot. Since it measured keeping the ankle joint at 90 degrees in this
experiment, inertia was very minute and can be omitted. The visco-elasticity can be found using the
formula for the moment of the circumference of this leg joint and this experiment. If this
visco-elasticity value is used for the parameter of the visco-elasticity of an orthosis, it is thought that
orthodontics of the foot can be performed appropriately.

Conclusions
The purpose of this study was to experimentally determine the feature point of ankle during gait. We
will have to consider how the outcomes of measurements should be processed as parameters in the
design of 3DCAD. When we measure the spasticity in the gaits, it is important to take special care to
measure the tendency to counter the force of drop foot. This study is an initial stage in 3D_designing
system of AFOs.

References
1. A.D.Pandyan. C.I.M. Price.H. Rodgers. M.P.Baranes. GRJohnson. (2001).Biomechanical
examination of a commonly used measure of spasticity. Clinical Biomechanics: 2001.16.859-865
2. Christopher. L.Vaughan, Brian L. Davis, Jeremy C.O'Connor. (1992). Dynamics of Human Gait.
Human Kinetics Publishers.
3. Sergio T. Fonseca, Kenneth G Holt, Elliot Saltzman, Linda Fetters. (2001). a dynamical model of
locomotion in spastic hemiplegic cerebral palsy: influence of walking speed. Clinical
Biomechanics. 16. 793-805
4. Y.Ebara, T.Tubota, T.Tuchiya, T.Nosaka, S.Yamamoto. (2002).Biomechanics of an AFO. MDP.
5. Y.Ebara, S.Yamamoto. (1997). Analysis of Gait by joint moments. Clinical walk analysis study
group.MDP.