ELECTROMYOGRAPHIC AND NEUROMUSCULAR FATIGUE THRESHOLDS AS CONCEPTS OF FATIGUE IN ROWERS

Objectives: To investigate the concepts of electromyographic threshold (EMGT) by iEMG signals and neuromuscular fatigue threshold concepts in trained male athletes. Methods: Nine competitive national level male rowers (21.8±4.4 years; 186.2±4.6 cm; 79.6±8.4 kg) took part in this investigation. Subjects were asked to participate in the graded exercise test to volitional exhaustion and 500m, 1000m, and 2000m all-out rowing ergometer tests on rowing ergometer. During the all tests oxygen consumption parameters, average power and integrated EMG of the musculus vastus lateralis was recorded. Results: The ventilatory threshold (VT) (248.9±26.67 W) and EMG threshold (258.89±27.13 W) were not significantly different but were significantly (p<0.05) lower than neuromuscular fatigue threshold (NMFT) (302.25±45.10 W). NMFT did not show any relationship with VO2 parameters (r=0.57; p>0.05). However, no relationship was detected between NMFT and VT and EMGT parameters, while significant relationship was found in VT and EMGT. All measured threshold values were significantly correlated (r>0.70; p<0.05) to the rowing ergometer performance characteristics. Conclusions: EMGT is closely related to aerobic-anaerobic transition phase as NMFT represents the local fatigue accumulation in the muscle