Surface electromyography changes of male athletes during 2000 m rowing ergometer test

This study aimed to investigate the changes in surface electromyography (EMG) in four anatomical segments of three muscles during a 2000 m rowing ergometer test. 19 healthy male rowers were requested to perform the test. Surface electrodes were attached to their vast medialis (VAM), erector spinae (ERS) and latissimus dorsi (LD) muscles. Raw EMG signals were presented at five different distance points: start (D0), 500 m (D1), 1000 m (D2), 1500 m (D3) and 2000 m (D4). The mean velocity and power were greater during 0-500 m and 1500-2000 m phases compared to 500-1000 m and 1000-1500 m phases (p < 0.01). Integrated Electromyography (iEMG) of VAM was significantly higher at the start and 2000 m compared to consecutive points (p < 0.05). The peak root mean square (pRMS) of ERS muscles was significantly higher at the start and 2000 m (p < 0.05). The frequency domain indexes mean frequency (MNF) and median frequency (MDF) of all muscles were significantly reduced at 1500 m compared to 1000 m (p < 0.05). However, no significant changes were observed in time domain indexes of LD muscles at any distance points (p > 0.05). A "fast start-speed maintains-final sprint" pacing pattern was observed during the 2000 m all-out rowing ergometer test. The EMG activation rates of VAM and ERS muscles were greater at the start and final phases, contributing to the increase in power. The decline in MNF and MDF of all three muscles at 1500 m could be related to greater muscle fatigue at this point. When using EMG to analyze endurance exercise, the results were dependent on the length of the test. Although not all EMG indexes were sensitive enough to detect these changes, combing them with different indicators for a comprehensive analysis might be considered.