The Impact of microbreaks with simplified ID stretches on muscle fatigue: Insights from EMG and MMG frequency analysis during suture ligation training

Prolonged surgical procedures contribute to musculoskeletal fatigue among surgeons, potentially shortening their career span. To address this issue, this study investigated the effects of microbreak (MB) interventions on muscle fatigue during suturing and tying training by analyzing electromyography (EMG) and mechanomyography (MMG) signals. Twelve male engineering students (8 without MB, 4 with MB) participated in the study. Biosensors were attached to the upper trapezius (UT) and anterior deltoid (AD) to measure EMG and MMG signals during the training. The frequency range for EMG was set at 10–350 Hz, and for MMG at 1–250 Hz. Short-time Fourier transform (STFT) and continuous wavelet transform (CWT) analyses were conducted. Subjective fatigue assessments were also performed to complement these analytical results. The MB intervention limited the reduction in the mean power frequency (eMPF) of AD EMG to approximately 2.1%. CWT analysis of EMG and MMG revealed that, under the no-MB condition, low-frequency components (LF/TP) increased by approximately 7.3% and high-frequency components (HF/TP) decreased by approximately 5.8% ( p < 0.01). Subjective fatigue levels reported under the MB condition indicated reduced fatigue in the neck and shoulders compared to the no-MB condition, although an increase in lumbar fatigue was observed. EMG and MMG analyses demonstrated that MB interventions effectively mitigated the progression of muscle fatigue, particularly alleviating fatigue in the neck and shoulders. These findings suggest that implementing MBs could be a promising approach to reducing musculoskeletal strain during prolonged surgical procedures.