Biomechanics is a movement science that examines the application of movement principles and techniques to the structures and functions of any living organism. Biomechanical analysis of an activity is often used to explain proper technique and can act as a how-to for that particular activity. Applied to the activity of running, biomechanics examines how the body moves and the effects that repeated contact with the ground has on the body. The biomechanics of running is often used to increase a runner’s efficiency and reduce his or her chance of injury.
To study the biomechanics of running, the running cycle is typically broken down into phases. During the first phase, one foot is making contact with the ground, and the other leg is swinging forward. This is followed by a phase in which both feet are off the ground. The second foot then makes contact with the ground, and the first leg continues to swing. Another phase in which both feet are off the ground follows before the cycle begins again.
When running, action of the the arms and legs usually is synchronized, with the opposite arm and leg moving forward at the same time. For the most part, the arms are held low and relaxed. The arms generally are bent at about 90-degree angles and remain loose, allowing the angles to move slightly in either direction.
The biomechanics of running show that the hips, knees and ankles provide most of the propulsion for the act of running. These joints flex as the foot comes into contact with the ground to cushion the landing. As the runner pushes off, these joints extend to give the thrust needed for forward motion.
Many runners land with what is called a heel-strike, meaning that the heel is the first part of the foot to make contact with the ground on each stride. This can put a lot of undue pressure on the ankles, knees and hips. Researchers and scientists who study the the biomechanics of running have found that it is more effective for runners to land on the balls of their feet, with what is often called a mid-foot strike. The mid-foot strike tends to reduce the stress that running puts on the knees and lessens the pressure that running places on the hips and ankles.
The majority of running injuries occur to the lower limbs during the phase in which the foot is coming into contact with the ground and the ankle and knee joints are at their greatest point of flexion. By decreasing the stress placed on the joints at all phases of the running cycle, especially when making contact with the ground, runners are less likely to suffer injuries because of overuse. Using the proper biomechanics of running, an individual can reduce his or her chance of injury while running.