The acute effect of neuromuscular electrical stimulation on optimum power performance in healthy individuals

Background: This study examines the acute effects of neuromuscular electrical stimulation (NMES) application on peak power (PP) and mean propulsive power (MPP) during a weighted squat jump (SJ(Loaded)). Methods: Fourteen male students (age: 23.71 +/- 2.30 years; height: 173.71 +/- 6.89 cm; weight: 69.59 +/- 9.08 kg; body mass index (BMI): 26.87 +/- 3.49) from the Faculty of Sport Sciences participated voluntarily. PP and MPP values were measured during the SJ(Loaded) movement, performed with an external load of 40% body weight, using a computer-integrated linear velocity transducer system (T-Force Dynamic Measurement System Ergotech Consulting SL, Murcia, Spain). NMES was bilaterally applied to the musculus hamstring and musculus quadriceps femoris for 20 minutes. The Shapiro-Wilk test, skewness and kurtosis values assessed data normality. Results: Differences between pre- and post-test PP and MPP power performances were analyzed using Paired Samples t-tests. Cohen's d (ES: effect size) and 95% confidence intervals (CI) were also calculated to assess the pairwise comparisons' magnitude. According to the analysis results, statistically significant improvements were observed in both PP (t (13) = -2.612, p = 0.021, d: -0.69 (-1.27; -0.10, 95% CI)) and MPP (t (13) = -2.756, p = 0.016, d: -0.73 (-1.32; -0.13, 95% CI), moderate effect) values after the NMES application. Conclusions: NMES significantly enhances PP and MPP during loaded squat jumps, highlighting its potential as a supplementary training tool for improving explosive power. Future studies should explore its long-term effects across different sports and populations, such as female athletes or older adults, to optimize training protocols. Research on NMES intensities and frequencies may provide insights into optimal parameters for power development and neuromuscular adaptation.