Objective
To investigate the effect of distant muscle contraction on the sensory and motor nerve conduction and F-wave studies in stroke patients. Method: During isometric contraction of contralateral hand, sensory nerve action potential (SNAP), compound muscle action potential (CMAP) and F-wave of median nerve were recorded at submaximal and supramaximal stimulus intensity. The subject group consisted of 15 stroke patients and 10 control subjects. Results: At submaximal stimulation, the amplitude and area of SNAP were significantly increased during muscle contraction in both groups (p＜0.05). However there were no changes in parameters of SNAP and CMAP at supramaximal stimulation in both groups. The latency of F-wave was prolonged, and the amplitude was increased in the stroke group than those in the control group at resting state (p＜0.05). The shortening of F-wave latency and increment of F-wave amplitude were observed in the control group during distant muscle contraction, but not in the stroke group. Conclusion: The distant muscle contraction might facilitate the nerve conduction. In addition F-wave elicited during voluntary contraction can be used as a monitor of upper motor neuron disorders. (J Korean Acad Rehab Med 2005; 29: 50-57)

Objective
To investigate the effect of distant muscle contraction on the sensory and motor nerve conduction and F-wave studies. Method: During isometric contraction (10%, 25% and 50% of maximal voluntary contraction) of dominant hand using hand held dynamometer, sensory nerve action potentials (SNAPs), compound muscle action potentials (CMAPs) and F-waves were examined on contralateral upper and ipsilateral lower extremities in 20 healthy adult subjects. SNAPs of median and sural nerves, CMAPs and F-waves of median and tibial nerves were recorded with submaximal and supramaximal intensity stimulation. Results: At submaximal stimulation the amplitudes and areas of median and sural SNAPs and median nerve CMAPs were significantly increased during distant muscle contraction (p＜0.05). Distant muscle contraction did not effect on the parameters of SNAPs and CMAPs at supramaximal stimulation. The latencies of F-waves were significantly shortened and amplitudes of F-waves were increased during distant muscle contraction (p＜0.05). Especially the amplitudes of F-waves were significantly positive correlated with the level of muscle contraction (p＜0.05). Conclusion: SNAPs and CMAP were augmented by the distant muscle contraction only submaximal stimulation. Due to facilitation, the distant muscle contraction should be considered during routine F-wave studies. (J Korean Acad Rehab Med 2004; 28: 48-53)