Effects of Belt Electrode-Skeletal Muscle Electrical Stimulation on Lower-Extremity Muscle Temperature

Introduction Warm-ups are essential for optimizing physiological readiness before physical activity, and active warm-up methods increase muscle temperature and neuromuscular activation. However, excessive exertion can lead to fatigue. Belt electrode-skeletal muscle electrical stimulation (B-SES) enhances muscle flexibility and prevents atrophy; however, its effectiveness in increasing muscle temperature as a passive warm-up strategy remains unclear. Therefore, we aimed to examine the effects of B-SES on lower limb muscle temperature. Methods This cross-sectional study comprised 20 healthy adults randomly assigned to either a low-frequency (LF; 4 Hz) or high-frequency (HF; 20 Hz) B-SES condition. Electrical stimulation was applied to the dominant lower extremity for 10 min, and the muscle temperature was measured every minute during and after stimulation. Temperature changes over time and between groups were analyzed using repeated-measures two-way analysis of variance (ANOVA). Repeated-measures one-way ANOVAs were conducted as post hoc analyses. Results Muscle temperature significantly increased over time in LF and HF conditions (p < 0.01), starting from 2 min of stimulation (at 2 min, LF: 0.24 ± 0.04℃; HF: 0.18 ± 0.04℃). However, no significant differences were observed between the two stimulation conditions (p = 0.09). The median fatigue rating on the visual analog scale was 31.5 mm (interquartile range, 14.8-60.8 mm). Conclusion B-SES effectively increased the muscle temperature within a short duration, suggesting its potential as an efficient passive warm-up method. Further research is required to explore its functional benefits in athletic performance and rehabilitation settings.