Training conditions that best reproduce the joint powers of unsupported walking

- Joint powers of walking (slow, comfortable speeds) are preserved at 30% BWS.
- Losses in joint power associated with clinical training parameters are reported.
- Some losses at higher speeds can be ameliorated by applying body weight support.

ObjectiveTo identify the clinically relevant combinations of body weight support and speed that best reproduce the joint powers of unsupported walking.MethodsTiming and magnitude of lower extremity joint powers were calculated for 8 neurologically intact volunteers (4M/4F) walking with 0%, 30% and 50% body weight support at three speeds (slow, comfortable, and fast). Lower extremity joint power absorption was analyzed during weight acceptance and forward propulsion. In addition, power generation was analyzed during forward propulsion. Timings and magnitudes of joint powers per condition were evaluated to identify the training combinations of body weight support and speed that best preserved the powers of unsupported walking at slow, comfortable and fast speeds.ResultsFor all speeds examined, increasing body weight support to 30% without changing speed provided the best match. In general, changes in speed disrupted the joint power magnitudes and timings more than application of body weight support. Increasing body weight support when faster training speeds were used proved a viable method for reproducing the joint powers of slow, unsupported walking.ConclusionsThese data provide a reference for understanding the effect of potential training conditions on power absorption and generation within the lower extremity joints during walking. It is possible to reproduce the joint powers of unsupported walking with certain combinations of body weight support and speed. We recommend applying adequate levels of BWS when training speeds are faster than the overground speed goal, as occurs during treadmill-based locomotor rehabilitation of individuals with incomplete spinal cord injury.