Analysis of Pulse Duration of Neuromuscular Electrical Stimulation on the Femoral Nerve

Neuromuscular electrical stimulation is a method widely used as an additional tool to evaluate the neuromuscular function. The difference of pulse duration can influence the torque and Electromyography, however, their effects have not widely studied. Therefore, the aim of the study was to analyze the effects of pulse duration on torque as well as in electromyography using the M-wave method of analysis. Six different electrical stimulus were applied on the femoral nerve of a healthy subject.

Two protocols were followed to determine the effects of the pulse duration following the twitch interpolation technique, used to assess fatigue. The current was increased to determine the current necessary to obtain a plateau of the M-wave. The parameters to be analyzed were the amplitude peak to peak, time to peak to peak and the integral of the Mwave. Additionally, the torque was assessed during maximal voluntary isometric contraction of vastus lateralis and after the contraction, during relaxation. Voluntary activation level was compared for different pulse duration. No difference were found in voluntary activation level, while integral of M-wave showed to have difference. Finally, it was discussed the appropriate duration pulse to be used when analysis of fatigue is performed.