Methods have been developed to study excitatory and inhibitory reflexes during human movements because dramatic task-dependent changes occur between different voluntary activities, and phase-dependent changes occur within cyclic movements. Interestingly, segmental reflexes are relatively unimportant for standing balance, although reflex responses are strong, yet they contribute substantially to force in several muscles during walking, when some reflex responses are weaker.
Improved methods for studying reflexes during human movement illustrate their important, adaptive function.
1Department of Physiology, University of Alberta, Edmonton, Alberta, Canada; and 2Wadsworth Center, New York State Department of Health, Albany, NY
Address for correspondence: Richard B. Stein, Department of Physiology, University of Alberta, 513 Heritage Medical Research Centre, Edmonton, Alberta, Canada T6G 2S2 (E-mail: Richard.Stein@Ualberta.ca).
Accepted for publication: June 14, 2006.
Associate Editor: E. Paul Zehr, Ph.D.