INTERACTION BETWEEN MUSCLE-STIFFNESS AND STRETCH REFLEX SENSITIVITY AFTER LONG-TERM STRETCH SHORTENING CYCLE EXERCISE

The short latency stretch-reflex component (M-1) and its interactions with muscle stiffness and with muscle performance were investigated be fore and after long-term stretch-shortening cycle (SSC) exercise. Dram atic fatigue induced reduction in maximal SSC performance capability, and electromyographic activity was accompanied by a consistent decreas e in the M-1 reflex component and eccentric peak stiffness of the musc le. It can be suggested, therefore, that the decreased muscle performa nce is not simply a direct effect of central or peripheral fatigue, bu t is partly due to impairment of the ability to utilize stiffness-rela ted elastic energy. (C) 1998 John Wiley & Sons, Inc.