Tohoku J. Exp. Med., 2003, 200 (1)

A Computer Simulation of Human Walking in Persons
with Joint Contractures

HITOSHI KAGAYA, SHUNICHI ITO,¹ TAKEHIRO IWAMI,²
GORO OBINATA³ and YOICHI SHIMADA⁴

Department of Rehabilitation Medicine, Akita City Hospital, Akita 010-0933,
¹Graduate School, Akita University, Akita 010-0852,
²Tsuruoka National College of Technology, Tsuruoka 997-8511,
³Department of Mechanical Engineering Faculty of Engineering and Resource Science, Akita University, Akita 010-0933, and
⁴Rehabilitation Division, Akita University Hospital, Akita 010-8543

Joint contractures decrease the patient's ability to walk, but usually other parts of the body compensate the affected joint contractures. When we restore the gait performance in paraplegic patients by means of functional electrical stimulation, however, we cannot expect complications of compensation. A computer simulation was done to clarify how the contractures affect the gait pattern when no complications of compensation were expected. A seven-segment link mechanical model was used for simulation of human walking in the sagittal plane. In turn, using a personal computer stance and swing-leg joint contractures of the ankle, knee, and/or hip were simulated. When stance-leg contracture was simulated, step length became short with increasing hip flexion contracture. The trunk was tilted backward during knee flexion or ankle plantarflexion contracture simulation. When the swing-leg contracture was simulated, step length became short with increasing knee flexion contracture. We found that hip or knee flexion contracture of ≦15°, or ankle plantarflexion contracture of <0° was required to maintain positive step length and forward movement of the center of gravity. These findings suggest that 15° of hip and knee flexion contracture, and 0° of ankle plantarflexion contracture are critical when gait restoration is performed by functional electrical stimulation.

keywords —— joint contractures; computer simulation; gait; functional electrical stimulation

© 2003 Tohoku University Medical Press

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Tohoku J. Exp. Med., 2003, 200, 31-37

Address for reprints: Hitoshi Kagaya, M.D., Ph.D., Department of Rehabilitation Medicine, Akita City Hospital, 4-30 Kawamoto-Matsuoka cho, Akita 010-0933, Japan.