Abstract des Autors

Despite complex control systems, human gait is characterised by smooth, regular and repeating movements. Such coordinated motion occurs as a direct result of the cyclical activation of many leg muscles. It is the tension in these muscles that serves as the direct cause of the kinematic patterns that we observe and recognise as locomotion. The challenge facing biomechanists, however, is that there are many more muscle activators than independent equations defining the system. This leads to the classic indeterminate problem. Engineers have circumvented this problem by means of a mechanical ruse: all muscle, bone and ligament forces are reduced to a single (vector) resultant joint force and torque. Using an inverse dynamics approach, the joint torques may be estimated and it has been proposed that they are the causative factors that help biomechanists understand how gait is achieved. This is the approach that we followed at the University of Virginia over the past 5 years. In this paper, we will review the data from our own studies, exploring both the advantages and disadvantages ot the joint torque approach. Our target populations have included: normal children; cerebral palsy children with orthoses; ankle inversion-eversion in level gait; knee abduction-adduction in stair climbing; and athletes with torn anterior cruciate ligaments. While this quest should be an interesting journey, offering a few fleeting glimpses of biomechanical insight, our final destination does not yield the Holy Grail. Verf.-Referat