Assessment of neuromuscular electrical stimulation effect on contralateral quadriceps muscle

In the field of rehabilitation, the acute application of neuromuscular electrical stimulation (NMES) causes not only peripheral muscle contraction but also involve the central nervous system by the transient increase in spinal motor neuron and cortical activity. Therefore it has been used in several fields of rehabilitation. Previous studies used surface electromyography to assess this effect. But we conducted our study to assess the effect of NMES on contralateral quadriceps muscle in normal individuals using another method needle electromyography.

A study carried out on 20 normal males, who were subjected to (i) NMES Training Program for 60 min for the right quadriceps muscle. (ii) Assessment of EMG activity for rectus femoris muscle (RF) on the contralateral side. An assessment was done for minimal volition and maximal volition or interference pattern analysis, this assessment was done twice: before the start of NMES and during the session.

EMG of voluntary activity (Minimal volition) and Maximum voluntary activity analysis for RF muscles showed increased duration (in millisecond), amplitude (in millivolt) (P < 0.01), increased activity in turn per second, amplitude/turn (M) (uV) compared to the result before NMES application.

Our study provides a new evident date that the acute NMES application to the contralateral quadriceps muscles, leads to significant facilitation of the maximal voluntary power in the ipsilateral muscles through activation of efferent neural control. This facilitating effect of motor neurons in the contralateral muscles is likely due to the complex combination interaction between spinal and supraspinal control.

Trial registration: PACTR202010887172053.