Spontaneous sympathetic command to skeletal muscles: functional implications.

The sympathetic system can influence skeletal muscle function through an action exerted at the peripheral level, namely on muscle spindle afferent information and muscular contraction. Data supporting such a conclusion are briefly reviewed. Also, the results described in the present paper suggest that the sympathetic nervous command affecting muscle function is tonic in nature and that it can be modulated by inputs which are known to influence other sections of the sympathetic system.