Running - Motion

Motion

Humans leap from one leg to the other while running. Each leap raises the center of gravity during take-off and lowers it on landing as the knee bends to absorb the shock. At mid arc, both feet are momentarily off the ground. This continual rise and fall of bodyweight expends energy opposing gravity and absorbing shock during take-off and landing. Running on a track requires more energy per unit distance than walking to cover the same distance. As reported by Hall et al. males on a track running at a pace of 2.82 m/s use 1.41 times as much energy to travel the same distance as walking at a pace of 1.41 m/s, with similar values on a treadmill. Therefore, running is less efficient than walking in terms of calories expended per unit distance, though it is faster.

In 2004, scientists at the University of Utah and Harvard University hypothesized that the ability of humans to sustain long-distance endurance running may have been instrumental in the evolution of the human form.