The effects of bracing and knee flexion angle on hamstring activity during crutch walking: A preliminary study for post-operative care

AbstractObjectives: To determine if immobilization of the knee at varying degrees of knee flexion will limit the surface electromygraphical (sEMG) activity of hamstring muscles during crutch-assisted ambulation. Methods: Ten healthy participants walked with crutches with the knee maintained at 0, 30, 60 and 90° of knee flexion, both with and without a brace. The leg was non-weight bearing for all trials except for those with the knee at 0° of flexion, when subjects performed a ‘toe-touch’ gait. sEMG was used to record activity of the biceps femoris and semitendinosus during trials. Results: For the semitendinosus, there were no differences between braced and unbraced conditions at 0° (22.5 vs. 23.2%), 30° (37.5 vs. 28.7%), 60° (47.2 vs. 44.6%), and 90° (32.7 vs. 51.8%) of knee flexion (all, p > 0.05). Similarly, for the biceps femoris, there were no differences between braced and unbraced conditions at 0° (22.5 vs. 23.2%), 30° (44.5 vs. 28.7%), 60° (47.2 vs. 44.6%), and 90° (32.7 vs. 51.8%) of knee flexio...