Comparison of the effects of two neuromuscular electrical stimulation protocols on the isometric muscular strength of the quadriceps

Abstract

Neuromuscular electrical stimulation (NMES) is an important resource used in physiotherapy to accelerate recovery processes, showing positive results with regard to re-establishing strength. Different NMES protocols may also interfere with the results obtained that process. This being so, the aim of this research was to analyze the effect of two NMES protocols on the strength of the quadriceps muscle of the thigh of the non dominant member of 18 volunteers of the female Sex (aged 19,5+-1,7). The NMES protocol comprised two currents with a symmetric, quadratic, diphase pulse, with Ton-Toff of 5 seconds, one being of an average frequency (2500 HZ modulated at 50Hz) and the other of low frequencu (50 Hz). Stimulation was for 30 minutes daily, comprising 15 a total of sessions. The volunteers stayed sat down with flexão of 90º of the thigh and of the leg, so much for both application of the NMES and the for the strength measurement, which was collected by means of a charging cell. The signal was obtained a maximum voluntary isometric contraction of 4 seconds, being amplified and calibrated to be expressed in kilograms-strength (Kgf). The results demonstrated that there was a significant in increase in strength (p>0,05) in the electrically stimulated groups both at low (40,5%) and at high frequency (44,6%). Based on the results, we may conclude that irrespetive of the parameters of the current, NMES promoted increase in the strength of the quadriceps muscle of the thigh.