Effects of Diverting Activities on Electromyographic Amplitude and Mean Frequency

The purpose of this study was to examine the effects of diverting activities on electromyographic amplitude and mean frequency. On three separate occasions, eleven men and eight women performed two bouts of fifty consecutive maximal concentric isokinetic muscle actions of the dominant leg extensors. Between these bouts, the subjects either solved math problems, performed contralateral dynamic constant external resistance leg extensions, or rested quietly. During each muscle action, electromyographic signals were detected from the vastus lateralis, rectus femoris, and vastus medialis. The results indicated that neither the mental nor the physical diverting activities consistently affected the mean electromyographic amplitude and mean frequency values relative to the control visit of quiet resting. If mental or physical diverting activities affected muscle activation in the vastus lateralis, rectus femoris or vastus medialis, electromyographic amplitude and mean frequency values were not sensitive enough to detect it.