EMG Analysis of Lower Limb Muscles for Developing Robotic Exoskeleton Orthotic Device

Human walking is a complex and rhythmic activity. It is well integrated effort of brain, nerves and muscles. It relies on the coordinated action of various muscles to control the jointed trunk and limbs and to generate the forces needed to counter gravity and propel the body forward. In this study, surface electromyography (EMG) signals of the gluteus maximus, gluteus medius, adductor longus, hamstrings, tibialis anterior, Tricep surae, rectus femoris and erector spine muscles were recorded on various subject walked over ground at normal walking speeds. Comparative study of the normal gait with clinical gait exhibited greater activation of the hamstring and tricep surae during mid-stance phase. The complete lack of triceps surae signal during the pushoff phase was also seen. Tibialis anterior showed activation throughout most of the gait cycle in clinical gait. During the walking, EMG activity of Adductor Longus, Hamstrings, Tibialis Anterior, Tricep Surae and Erector Spine muscles were significantly augmented (p<0.05) in both normal and clinical gait. There were no significant differences (p < 0.050) shown for muscle EMG for the gluteus maximus, gluteus medius and rectus femoris muscle. The biomechanical lower extremity model proposed in this study will estimate the muscle activation patterns and also be used to design the lower-limb exoskeltal assistive robotic systems for physically challenged persons.