Dynamic optimization of transfemoral prosthesis during swing phase with residual limb model.

A new simulation model was created with a transfemoral prosthesis including a residual limb muscle model during the swing phase. The optimal knee joint friction value was calculated to minimize muscle metabolic energy expenditure. Using this model to examine how an amputee could walk as fast as possible, the minimum swing duration was calculated. The obtained optimal joint friction value was close to the value the subject preferred when walking normally. The calculated minimum swing duration was close to the time the subject could achieve. The method of dynamic optimization with a musculoskeletal model used in this study indicated the possibility of obtaining optimal mechanical properties suited to each amputee's capability of mastering control of his/her residual limb.