Running
Running, movement of the body in which it is alternately lifted off the ground by the feet and floats in the air for a moment. If the body is propelled off the ground while running, while keeping the center of gravity supported, one will run in place and not move forward. However, great speed is attained when one brings the center of gravity as far forward as possible by tilting the body, then pushes the body strongly forwards and upwards off the ground and, while floating in the air, throwing the other leg as far forward as possible to catch the body. The illustration shows the phases of movement of a running person based on photographic snapshots. One can clearly see the moments of floating when neither foot touches the ground. The faster the run, the longer the body floats unsupported in the air and the shorter the contact with the ground.
The run of humans is the equivalent of the trot of animals. In this gait, the body weight is supported alternately by the two diagonal pairs of feet, so that the right forefoot touches the ground at the same time as the left hindfoot, and the left forefoot touches the ground at the same time as the right hindfoot. Since the supporting pair of feet is lifted off the ground before the moving one has touched down again, the body must float in the air for a while. At the horse‘s extended trot this time is longer than at the short trot. Photographic snapshots of trotting horses revealed that the diagonally positioned fore and hind limbs do not work in unison, but that the former leave the ground a little earlier than the latter. It is therefore possible to capture images in which the horse only touches the ground with one hind leg. The horse‘s gallop gait corresponds to the jump of a human being (see jumping).
Source: Meyers Großes Konversations-Lexikon, 6. Auflage 1905–1909