摘要或動機

Space Medicine and relevant sciences are still considered a new era; the first humankind steps toward the space took place since less than 60 years. It has been noticed the adverse effects of microgravity on the human body in different aspects, our concern here is the musculoskeletal aspect. On the ground we didn’t notice how we can stand up, or how our muscles and bones of the lower limbs can keep us standing up right. This is by a complicated process including the bones, the equilibrium, and the anti-gravitational muscles of the lower limbs which occurred without thinking about it. The force of Earth gravity against our bones of the lower limbs makes them harder and makes the muscles stronger, because they are interfacing the earth gravitational force every moment we are standing up, as per Newton’s third law (for every action in nature there is an equal and opposite reaction), such forces are unavailable in space and its effect being obvious on arrival to earth after long stay space flights, so being unable to keep standing upright easily on their arrival. On return to earth the routine medical examinations revealed loss of astronaut muscle mass and bone density particularly of their lower extremities because they did not use them in space for a long time. Currently, astronauts on board of ISS (International Space Station) they accomplish daily tasks including resistive exercises ARED “Advanced Resistive Exercise Device” in form of treadmill, ergometer, and weightlifting machine, to decrease the loss of bone density and muscle mass of their lower limbs. Despite their discipline to those exercises they still lose 1-2% of the muscle mass and bone density that give importance to add some protective measures to keep their muscles and bones healthy. Through this article, the idea is to make a device such AACT (Automated Alternative Compression/Traction) to be applied daily to the astronauts lower limbs as part of their daily exercise during space flight to give push/traction forces to astronauts lower limbs to prevent or at least decrease such loss, by AACT we are mimicking the gravitational force of earth on astounds lower limbs during long space flights to let them be healthy till they come back.