Can a powered knee-ankle prosthesis improve weight-bearing symmetry during stand-to-sit transitions in individuals with above-knee amputations?

The study included only ten participants, all of whom were able to stand and sit, limiting generalizability to those with more severe mobility impairments. Three subjects required hand support during sit-down and were excluded from inverse dynamics analysis, potentially biasing the kinetic results. The powered prosthesis was a research device, not a commercially available product, and required individual tuning for each subject. Participants had no prior experience with the powered device, which may have influenced their muscle activation patterns due to a learning effect. The study was a within-subject comparison without a long-term follow-up to assess adaptation or sustained benefits.

The authors declared no conflicts of interest. The work was supported by the National Institutes of Health, U.S. Department of Defense, National Science Foundation, and the Rocky Mountain Center for Occupational and Environmental Health.

Do not conclude that powered prostheses reduce physical effort for the intact leg. While weight-bearing symmetry improved, the study found no significant reduction in intact-side quadriceps muscle activity, meaning the sound leg still works just as hard.