Electromyographic threshold intensity in athletes with different physical activity patterns

The aim of this study was to investigate the EMG thresholds in four lower limb muscles and to compare them with ventilatory threshold as an alternative for detecting aerobic-anaerobic transition intensity. 49 subjects (23.8+/-5.7 years, 182.7+/-5.3 cm, 79,1+/-8.6 kg) were investigated on cycle ergometer. Expired gas and EMG activity were recorded from vastus lateralis, vastus medialis, biceps femoris and gastrocnemius lateralis. Ventilatory threshold and EMG threshold from different muscle were not significantly different. When thresholds were analyzed among different groups of subjects no significant difference were observed between ventilatory threshold and EMG thresholds despite threshold differencies between the groups. All EMG thresholds were significantly related to maximal aerobic power (r=0.73-0.83) and were highly correlated to each other (r=0.57-0.88). It can be concluded that EMG activity from leg muscles provided an alternative when detecting subjects individual aerobic-anaerobic transition intensity