Rapid skilled movements by a human subject are executed at such a rate that conscious control can be no more than the strategic selection of a sequence of detailed tactical plans of control, which have previously been learned by the subject. By the use of transient changes in the force applied to various muscle groups, and computer analysis of the responses obtained, it has been possible to observe separately the roles of spinal reflexes, subroutines of motor impulses from the central nervous system, and conscious voluntary control.