Running differs from walking in several ways. While walking, humans push off the side of their feet while keeping the center of gravity over the leg taking the step. The motion finishes with a slow roll onto the toes. On the other hand, running keeps the body's center of gravity central to the torso. The foot meets the ground on the outside of the heel and rolls to the inside of the foot, an action known as pronation.
Based on the unique motion of running, today's shoe design for runners provides cushion, …show more content…
Absorption is also a key component. When the cushioning mechanism is able to absorb the force of impact, a good shoe can withstand between two and three times average body weight.
Advancement in materials for athletic shoes have led to the use of products called EVA and polyurethane. EVA is light and flexible although it can become compressed in the shoe after repeated use. Polyurethane is stronger and tends to last longer although it makes the shoe heavier than EVA. Shoe companies take advantage of the best qualities of both materials by combining polyurethane in the midsole with EVA in other parts of the shoe.
Proper shoe design ultimately results in less injury and pain for runners. Athletes who run over six miles per week can experience injury or pain in foot, legs or back without adequate shoe cushioning and support. Force of impact during running should not be taken lightly when it comes to proper shoe