[Effect of 7 d -6 degrees head-down tilt (HDT) on electromyogram of gastrocnemius and anterior tibialis muscles].
Objective. To assess the effect of 7 d -6 degrees HDT on electromyogram of the weightbearing muscles. Method. Eight healthy males, aged 33-42, were exposed to -6 degrees HDT bed-rest for 7 d, electromyogram from the gastrocnemius and anterior tibialis muscles were recorded before and after HDT, and day 4 of recovery. Result. The latency of SLR (short latency response) recorded from lower leg muscles after HDT was not different from that pre-HDT. But the latency of MLR (middle latency response) and LLR (long latency response) after HDT were significantly increased as compared with that pre-HDT, and recovered to pre-HDT level on day 4 of recovery. The durations of SLR recorded from right leg muscles after HDT were significantly longer as compared with that pre-HDT, and did not recover. The integrated amplitude of SLR and MLR after HDT were significantly increased as compared with that pre-HDT, and only the integrated amplitude of SLR recovered, but that of MLR did not. Conclusion. Seven day -6 degrees HDT bed-rest had significant effects on electromyogram of the weightbearing muscles.