Hypergravity and its effects on bones and the musculoskeletal system: a narrative review

them 2 . Two more centuries went by until Albert Einstein completely transformed our perception about gravity. In Abstract The entrance of mankind into the Space Age , accomplished by the second half of the 20 th century, and the advances in modern physics have completely transformed the way we perceive the role of gravity. The musculoskeletal system is long known to be heavily affected by the gravitational forces, resulting in marked loss in bone mineral density in the setting of microgravity. The meticulous study of the underlying pathophysiologic mechanisms is pivotal in order to identify possible therapeutic targets for the management of the microgravity-induced changes in bone physiology during spaceflight missions, as well as the osteopenia induced changes in the setting of osteoporosis affecting a vast majority of elder individuals. In the present bibliographic narrative review, the importance of mechanisms employed by cells in order to perceive and respond to altered gravity are discussed. Current in vitro and in vivo studies focusing on the effect of hypergravity on the musculoskeletal system are also presented. Overall, the variability in study design of the available published data makes the deduction of safe conclusions rather challenging and uncertain. It is important that future studies address the matter by employing similar research methodology and study design in order to increase the comparability of their results.