Myoelectric frequency changes in children during static force production.
Neuromuscular adaptations to a submaximal static contraction for a period of 2 min were investigated using children as subjects to detect changes in the contributing frequency components of the electromyogram (EMG) recorded from surface electrodes. The purpose of this study was to determine the similarity between EMG response patterns of children and published data for adult subjects under similar conditions. Spectral analysis of the EMG signal revealed a shift to lower frequency components and a concurrent increase in total variance of the signal as a response to fatigue. The frequency shift and increase amplitude for the EMG signal were discussed in light of evidence for recruitment and synchronization of motor units and changes in muscle fiber conduction velocity as possible mechanisms.