Does passive bi-articular coupling of joint moments in the lower extremity of paraplegics differ from normal persons?

Previous research has shown that significant coupling of passive, elastic joint moments between neighboring joints occurs in normal persons due to muscle groups that span both joints. In functional electrical stimulation of the lower extremity of paraplegics to achieve standing and walking, knowledge of this particular coupling is essential in order to implement model-based control algorithms. In this study, we investigated the bi-articular coupling in two representative paraplegic patients. A comparison with the averaged results of 10 normal persons showed characteristic differences for which we offer pathophysiologically based explanations.