Significant Lower Limb Muscles in Walking and Running for Design of Low-Cost Swing-Assist Rehabilitation Device

According to Census of India 2011, 26.8 million people are disabled and more than 20% of them suffer from a movement disability [1]. Furthermore, 68% of disabled population belongs to lower socio-economic class necessitating the need for developing low-cost yet high quality and high performance assistive devices as the current sophisticated devices developed in the western countries are not simply affordable to this population. The aim of this work is to propose a significant lower limb muscle model during swing phase for walking at 1 m/s and running at 4 m/s, to be used in the design of efficient low cost swing-assist rehabilitation device for lower limb amputees. Swing phase of 0.4s is considered here out of gait cycle of 1s and the proposed model consist of six muscles namely biceps femoris long head, biceps femoris short head, psoas, rectus femoris, soleus and tibialis anterior. The simulation results show greater muscle forces for running due to greater push needed for forward propulsion and more foot clearance. The largest change is observed in knee angle during initial swing to mid swing as it flexed more in case of running. The biarticular muscles rectus femoris and biceps femoris long head are responsible for energy transfer between hip and knee joints in the sagittal plane. The trajectory generated at hip, knee and ankle joint matches more than 98% and 83% for walking and running respectively.