An object in the technical sense of the term “free fall” may not necessarily be falling down in the usual sense of the term. An object moving upwards would not normally be considered to be falling, but if it is subject to the force of gravity only, it is said to be in free fall. From a physics point of view, this means that when the air flow rate reaches ca. 200 km/h (124 mph), the human body cannot fall down and keeps a constant altitude above the ground surface. By generating such a fast and stable air flow from the ground, conditions in which the body loses weight are created. Thus, people can enjoy the sensation of free fall by simulating skydiving.