Cross Exercise: A Comparison of Electromyographic Recordings During Maximal Static Performance of the Vastus Lateralis Muscle

The purpose of this study was to investigate the transient response of cross exercise during maximum static performance by electromyography. Thirty male athletes performed maximum static exercise at 115 degrees extension of the knee. Action potentials generated in this dominant exercising and nondominant, nonexercising vastus lateralis muscles were compared to determine whether or not the nonexercising muscle was affected during exercise. Surface electrodes were attached to both vastus lateralis muscles. The muscular impulses were recorded on a Grass Five Polygraph. The amplitude of the EMG tracings were then measured to determine the relative quantity of stimulus that each muscle received during exercise. A comparison of the exercising vastus lateralis muscle\u27s mean EMG amplitudes to that of the nonexercising vastus lateralis muscle provided the basis for analyzing cross exercise. The comparison indicated the nonexercising musculature\u27s mean EMG amplitude was eleven percent ■ of the exercising musculature\u27s mean EMG amplitude. The eleven percent cross exercise response was shown to be significant to the .01 level of confidence when compared to the resting EMG amplitude