DEPRESSED TETANIC CONTRACTILE FUNCTION CANNOT BE COMPENSATED BY INCREASING STIMULATING FREQUENCY IN UNLOADED SOLEUS MUSCLE

摘要

The weightlessness-induced muscle atrophy is associated with a reduced force and power and with an increased fatigability. In prolonged manned space missions, these alterations in skeletal muscles could limit the crew's ability to work in space and to rapidly egress in an emergency on return to Earth. In order to elucidate the underlying mechanisms of the increased fatigability in the atrophic skeletal muscle, we isolated the typically fast and slow muscle, extensor digitorum longus (EDL) and soleus (SOL), to observe the changes in maximal contraction tension, optimal stimulating frequency, and recovery features after fatigue in the intermittent tetanic contraction.