Running is an activity performed by many people to maintain good health. Running exercises the cardiovascular system and improves muscle strength. Running consumes more calories than less strenuous activity, and the benefits also include improve caloric consumption when not running.
Biomechanically, running is defined as a form of locomotion. During running, portions of the gait cycle include leaping where both feet are airborne. On impact with the ground, energy is stored in the elastic tissues and released later in the gait cycle. This makes running an efficient means of locomotion. Walking is a distinctly different activity than running. When walking, one of the feet is always on the ground and there are portions of the gait cycle where both feet are planted.
Because of these differences, the gait cycle for running differs from that of walking. Like walking, the running gait cycle begins with heel strike. Upon heel strike, the weight and momentum from the body is transferred to the foot, and energy is absorbed. This energy absorption continues throughout the initial portion of the stance phase, and center of mass continues to drop. During the latter portion of the stance phase, muscular contractions begin lifting the body upward and forward, changing the direction of the center of mass. This is known as the propulsion portion of the running gait cycle. Energy is added until the foot leaves the ground and the runner becomes airborne, a period known as double float. During the swing phase the leg is pulled forward into positon for the next heel strike.
