The effects of gravity on H-reflex in the human soleus mouscle during parabolic flight

The excitation of the spinal cord can be effected gravitational environment that can be evoked by exposure to weightlessness in the microgravity conditions of orbital and parabolic flight. This research described changing of the H-reflex amplitude by parabolic flight with exposure to micro and high-gravity. Four subjects participated in this parabolic flight experiment. The amount of H reflex amplitude was increased during microgravity. The higher H-reflex gain observed in this study and the high level of acute mental stress tasks suggest that the neuromuscular mechanism which control the excitability of these reflex pathway may be large effected from controlled environmental.