An Optimality Criterion for Processing Electromyographic (EMG) Signals Relating to Human Locomotion

Emphasizing consistency and repeatability of acquired data, we have studied the characteristics of surface EMG signals from m. vastus lateralis and m. rectus femoris during several steps of level walking under controlled repeatable gait conditions at three different speeds for several subjects. The variance ratio, a statistical descriptor for repeatability, has been devised. Our findings indicate that the variance ratio offers a simple means for selecting an optimal envelope processor of full-wave rectified EMG signals. It is of value also in determining an optimal location for surface electrodes on a muscle.