Isometric-based EMG threshold in girls and women.

Girls' EMGTh values are higher compared with women's, possibly reflecting lower ability to activate higher-threshold (type-II) motor units. The females' EMGTh and detection-rate values were similar to the corresponding values previously observed in males. The females' age-related difference in the recruitment of higher-threshold motor units, as reflected by the EMGTh, appears to be on par with the males.