Effects of powered versus passive-elastic ankle foot prostheses on leg muscle activity during level, uphill and downhill walking

People with transtibial amputation (TTA) using passive-elastic prostheses have greater leg muscle activity and metabolic cost during level-ground and sloped walking than non-amputees. Use of a stance-phase powered (BiOM) versus passive-elastic prosthesis reduces metabolic cost for people with TTA during level-ground, +3 degrees and +6 degrees walking. Metabolic cost is associated with muscle activity, which may provide insight into differences between prostheses. We measured affected leg (AL) and unaffected leg (UL) muscle activity from ten people with TTA (6 males, 4 females) walking at 1.25 m s(-1) on a dual-belt force-measuring treadmill at 0 degrees, +/- 3 degrees, +/- 6 degrees and +/- 9 degrees using their own passive-elastic and the BiOM prosthesis. We compared stride average integrated EMG (iEMG), peak EMG and muscle activity burst duration. Use of the BiOM increased UL lateral gastrocnemius iEMG on downhill slopes and AL biceps femoris on +6 degrees and +9 degrees slopes, and decreased UL rectus femoris on uphill slopes, UL vastus lateralis on +6 degrees and +9 degrees, and soleus and tibialis anterior on a +9 degrees slope compared to a passive-elastic prosthesis. Differences in leg muscle activity for people with TTA using a passive-elastic versus stance-phase powered prosthesis do not clearly explain differences in metabolic cost during walking on level ground and slopes.

Automated summary

People with transtibial amputation using passive-elastic prostheses have higher leg muscle activity and metabolic cost than non-amputees. Stance-phase powered prostheses can reduce metabolic cost for amputees. However, differences in leg muscle activity between different prostheses do not fully explain the differences in metabolic cost.