A group of Japanese scientists have studied how microgravity conditions can damage the skeletal muscles that are important for the maintenance of the posture. They are located on the limbs, back, and neck, and they are also called "aggressive" because they help to carry cargo, stand straight and move against gravity. The work of researchers suggests that the effects of microgravity can have significant consequences for astronauts returning after a long stay in space.
The team studied the neuromuscular properties of astronauts who spent a long time in space, and these muscles are located in the camouflage and inside of the thigh and are responsible for carrying the load and helping to maintain the vertical position in normal gravity. Under microgravity, these muscles are "unload" and have no effect, leading to a gradual atrophy of their fibers and nerves.
The study examined how the morphological, functional and metabolic properties of the nervous-muscular system respond to gravitational handling under microgravity and lower gravity conditions, and for this purpose they launched simulation models of human and rodents and studied how the signals of the moths between the skeletal muscle and the central nervous system regulate the neural properties.
Their analysis confirmed that these signals play a key role in regulating muscle properties and brain activity. They reduce the structural units of the muscles, resulting in reduced development, leading to atrophia. The results of the study show that low gravity conditions affect muscles and nerves, leading to a deterioration of motor control.
These findings coincide with the symptoms reported by astronauts upon their return to Earth, and they experienced difficulties in walking despite regular physical loads on board ISS, such as the use of treadmills, cyclers and resistance training, and their work showed that additional problems could arise if astronauts were in microgravity for six months or more, such as during a potential flight to Mars.
The study also indicates possible solutions to the problem. First, they recommend that the underlying muscle be stimulated during physical exercise, which can be done by running or walking slowly on the treadmill, landing on the back of the foot. The addition of cords for additional resistance and periodic passive stretching of the underlying muscle also reduces the risk of atrophia. This study can play an important role in developing appropriate countermeasures for future long-term space missions.