ABSTRACT
This paper investigates the optimal velocity for human walking. The subjects were children and adults (age range 8–40, height range 120–185 cm and weight range 10–85 kg walking at their subjectively selected ‘slow’, ‘normal’ and ‘fast’ velocities. Kinematic data (joint angles and angular velocity) were obtained by photogranunetric reconstruction using two orthogonal, genlocked video cameras. Ground reaction forces were measured using a Kistler forceplate. Joint moments and mechanical joint power were then calculated by inverse dynamic analysis. Results indicated that as the forward velocity of the body centre of mass increases, the mean powers for joints vary in different ways: the mean powers for ankle and hip increase with velocity, but the mean power for the knee decreases. Thus, when the forward velocity is smaller than 2 m/s, the sum of mean powers for all joints is almost unchanged. When the forward velocity is greater than this value, the sum increases very quickly. Therefore, in order to walk as fast as possible while minimizing necessary power output, a speed should be selected as close as possible to 2m/s.
