EVOLUTION OF HUMAN PHYSIOLOGY IN GRAVITY
Life evolved on earth in weightless conditions afforded by marine environments. It wasn’t until after vertebrate physiology had reached the level of sophistication similar to that found in Sharks (mastered the point and mastering the line) that Vertebrates began the arduous process of evolving to push and pull themselves over dry earth. Here in addition to mastering movement along a line, they were immediately confronted with the issue of Gravity. Initially, they dealt with their body mass by sliding it over the ground. However, our ancestors rather quickly figured out how to get their weight under their feet, greatly enhancing their speed and mobility.
Mammals greatly extended the solutions Vertebrates had employed to manage body mass, enabling fluid and flexible movements over the horizontal plane. One strategy they developed was shock absorption, where the energy when landing in a stride was returned to the next stride. BioTensegrity is a mechanical model which elegantly describes this fascinating capacity observed in mammalian gait.
Bipedal Primates are the ultimate masters of movement in gravity.
It is common to consider Gravity as a field, something like magnetism. Since Einstein, this is unlikely to be the case as is demonstrated by this brief description of the General Theory of Relativity:
SHORT GRAPHICAL PRESENTATION ON THE NATURE OF GRAVITY
IN/OUT VS. UP DOWN