Behaviour of EMG-parameters and conduction velocity in contractions with different muscle temperatures

In the study the effect of changing muscle temperature on EMG-parameters and muscular conduction velocity was investigated for ambient temperatures of 0, 10, 20, 30, 40 degrees C. With temperatures below 20 degrees C a striking diminution of EMG-amplitudes was observed despite nearly unchanged mechanical capability. The decrease in mean frequency of surface EMG was related directly to changes in conduction velocity during cooling of the muscle whereas in fatiguing muscle contractions the mean frequency seemed to be also affected by other mechanisms.