Training Effects Of Alternated And Pulsed Currents On Body Mass Of Competitive Athletes

Abstract

Neuromuscular electrical stimulation (NMES) is widely used for strength training in healthy individuals and athletes. Previous studies have shown that alternated mid-frequency currents (MF) and low-frequency pulsed currents (PC) have similar effects on quadriceps evoked strength and level of discomfort in this population. However, little is known about the effects and best parameters of NMES to induce body mass loss. PURPOSE: To evaluate the effects of 6 weeks of training with 2 different NMES currents - medium alternated and low frequency pulsed current - on body mass of competitive athletes. METHODS: A double-blind controlled and randomized experimental study was carried out with 33 athletes (22.2 ± 2.6 yrs, 74.7 ± 9.8 kg, 176.8 ± 6.0 cm), divided into 3 groups: mid-frequency current (MF, n=12), pulsed current (PC, n=11) and control group (CG, n=10). Body mass was assessed before and after the intervention through a body mass scale (BC-418, Tanita Corporation of America Inc., Illinois, USA). NMES training was performed 3 times per week and consisted of 18 sessions, 15 min/session (36 involuntary isometric quadriceps contractions per session), 6s duration in each contraction interspersed with 18s rest. Data were expressed as means ± standard deviation (SD) and normality was checked using the Shapiro-Wilk test. A two-way analysis of variance (ANOVA) with repeated-measures and Tukey post-hoc test were used to analyze data (group and time effects). Statistical significance was accepted with p < 0.05. RESULTS: After the training period, body mass did not change in any group (PRE: PC = 76.1 ± 8.1 kg, MF = 74.7 ± 9.8 kg, CG = 73.5 ± 21.5 kg; POST: PC = 76.7 ± 8.9 kg, MF = 74.7 ± 9.4 kg, CG = 74.0 ± 11.3 kg; p > 0.05). All currents produced similar evoked torque and levels of discomfort (p > 0.05). CONCLUSION: Quadriceps NMES training applied through alternated or pulsed currents produced similar effects and did not change body mass in competitive athletes.