Electromyographic analysis and energy expenditure of harness supported treadmill walking: implications for knee rehabilitation

Harness supported treadmill ambulation has been recommended for patients as a way of decreasing loads on the healing tissues, conserving energy and re ducing pain. We quantified muscle activation levels around the knee and met abolic responses during harness supported treadmill walking. Ten healthy re creational athletes (age 25.9 +/- 7.8 years) walked on the treadmill (1.34 m/s) for 5 min each at full weight bearing (FWB), 20 and 40% body weight su pport (BWS). Electromyography (EMG) was monitored for the vastus lateralis, vastus medialis, rectus Femoris, biceps femoris, medial hamstrings and the gastrocnemius. Oxygen consumption was collected by open circuit spirometry and the heart rate was collected by a heartwatch. A statistically signific ant reduction in EMG was found at 40% BWS for the quadriceps. Oxygen consum ption decreased by 6% (20% BWS) and by 12% (40% BWS) from FWB (P < 0.05). T he heart rate was unchanged. BWS ambulation reduces energy cost, but does n ot significantly alter muscle activation, except for the quadriceps at 40% BWS. (C) 1999 Elsevier Science B.V. All rights reserved.