DIFFERENT STRETCH REFLEX MECHANISMS IN ANKLE FLEXORS AND EXTENSORS REVEALED THROUGH SYSTEM IDENTIFICATION.

The objective of this study was to examine stretch reflexes in two muscles, the human ankle flexors and extensors, for which different stretch reflex responses have been described. The systems identification technique used to separate the influences of stretch reflex mechanisms from those of displacement trajectory, involved the deconvolution of the non-white input displacement perturbation from the EMG (electromyogram) response to determine the stretch reflex impulse-response function. There were a number of important differences between the reflex impulse-response functions obtained from the two muscles which must therefore be attributed to physiological causes. 2 refs.