Estimation of work done in lower limb using EMG

Estimation of human lower limb motions is elementary to enable power-assist robotic systems used for lower limb disabled persons. These robotic systems are based on lower limb muscles electromyographic (EMG) signals. EMG allows for the measurement of the change in the membrane as voltage from our muscles relates to work done. Apparently, there is no particular technique to estimate the mathematical relation between work done and surface EMG (sEMG) value of lower limb muscles. This study aims to propose a numerical model to estimate the muscle work done in the human lower extremity. This paper investigates the activity of the Biceps Femoris (BF) and Medial Gastrocnemius (MG) muscles of healthy subjects during lifting different known weight to a defined height and corresponding sEMG voltage is measured. It is observed that EMG voltage maintain almost non linear parabolic relationship with work done. We have also shown the accuracy of our proposed mathematical model considering all facts of errors numerically. A significant findings is that incrementing weight over 2 kg undergoes in saturated EMG potential, which means muscle fatigue creates in lower limb muscles in that situation.