MYOSTIM-FES to prevent muscle atrophy in microgravity and bed rest: Preliminary report

Long-term flights in microgravity cause atrophy and morphological changes o f skeletal muscles. Training with mechanical devices is insufficient regard ing the required time to exercise and space for devices. The objective of t his project is to develop a passive training method based on functional ele ctrostimulation (FES) to preserve muscle mass and fiber composition with mi nimal impairment to the cosmonaut. For a pilot experiment on the MIR space station, a suitable 8 channel FES device was developed. It consists of elec trode trousers that carry surface electrodes and cables, 2 interconnected 4 channel stimulators, and a laptop personal computer (PC) for stimulator pr ogramming and processing compliance data. An automatic extensive training o f 4 muscle groups of the lower extremities is performed for 6 h/day, with 1 s on and 2 s off tetanic contractions at 20-30 % of maximum tetanic muscle force. The synchronous activation of antagonists of the thigh and lower le g prevents uncoordinated movements.