The Effect of Prior Muscle Activation on the Compound Muscle Action Potential (CMAP)

The purpose of this investigator-initiated study is to determine the effect of prior muscle activation on the response obtained by nerve conduction studies (the compound muscle action potential \[CMAP\]) looking at the amplitude, area, and duration of the CMAP and evaluating the length of time the CMAP is larger than at baseline. On the opposite side, the corresponding CMAP will be tested periodically, but there will be no muscle activation on that side. Null Hypothesis: While controlling all possible technical and other known physiological variables, prior activation of a muscle has no effect on the amplitude and area of the compound muscle action potential (CMAP); and the CMAP does not change over time in the relaxed muscle (on the opposite side). The investigators suspect that there is an effect of prior activation of the muscle on the subsequent CMAP recorded from that muscle.