Effect of joint angle on EMG variables in leg and thigh muscles

It is the purpose of this article (a) to show the influence of electrode location on EMG amplitude and spectral variables for simulated and real signals for different muscles of the thigh and leg, (b) to investigate the relative movement of the muscle under the recording electrodes when the joint angle changes for the set of muscles most frequently investigated in gait analysis, and (c) to illustrate how different electrode locations may lead to different interpretations of the muscle activity investigated with amplitude and spectral analysis of the surface EMG signal. The study has been carried out on the following muscles of the leg and thigh: rectus femoris, vastus lateralis, vastus medialis, biceps femoris, semitendinosus, tibialis anterior, gastrocnemius lateralis, and gastrocnemius medialis.