On-line determination of anaerobic threshold with rms-EMG.

1. On-line monitoring of surface rms-EMG for detecting the anaerobic threshold during a cycle ergometer test was evaluated and compared with blood lactate and ventilatory parameters in 12 healthy icehockey players. 2. Dislinearity of increase in blood lactate level, ventilatory parameters and myoelectrical activity was observed at the mean work level of 300 (range 270-330) watts in each case. 3. The linearity disappeared at the same time in the rms-EMG-load ratio in working quadriceps and gastrocnemius muscles while also in nonworking frontalis muscle a change in EMG level was noticed. 4. The break point in rms-EMG did not correlate with the changes in skin humidity and temperature. No change was observed in spectral properties of the myoelectrical signals. 5. The rms-EMG follow-up is easier to perform than measurements of blood lactate and ventilatory parameters in the determination of anaerobic threshold.