Aerobic-anaerobic transition intensity measured via EMG signals in athletes with different physical activity patterns

The purpose of this study was to investigate the use of electromyographic signals (EMG), to determine the EMG threshold(EMGT) in four lower extremity muscles and to compare these thresholds with the second ventilatory threshold (VT2) in subjects participating in different sports and at different performance levels. Forty-nine subjects (23.8 +/- 5.7 years, 182.7 +/- 5.3 cm, 79.1 +/- 8.6 kg) including eleven cyclists, ten team-handball player, nine kajakers, eight power lifters and eleven controls were investigated utilizing a cycle ergometer. Respiratory gas exchange measures were collected and EMG activity was continuously recorded from four muscles (vastus lateralis. vastus medialis, biceps femoris and gastrocnemius lateralis). The V02max averaged 56.1 +/- 11.1 ml kg-1 min-1, the average aerobic power was +/- 348.5 +/- 61 W and the corresponding VO2 occourred at 271.4 +/- 64 W. The VT2 and EMGT ranged from 80 to 98% of power output for the different muscles. The VT2 and EMG thresholdsfrom four different muscles were not different, When thresholds were analyzed among different group of subjects, no significant difference was observed between VT2 and EMGT despite threshold differences between the groups. All four EMGT were significantly different related to maximal aerobic power (r = 0.73-0.83) and were higly correlated to each other (r=0.57-0.88). In conclusion, EMGT can be used to determine the VT2 for individuals independent of sport specificity or performance level