Racket sports involve sudden changes of movement. Unlike jogging or running in a straight line, racket sports involve stopping and starting, moving from side to side and twisting and turning. These movements create friction between the bottom of the feet and the shoes. This can result in hard skin and blisters under the balls of the feet.

The feet are also forced to slide backwards and forwards inside the shoes, causing bruised toenails. When the foot is planted on the floor, these movements also cause the muscles in the front and back of the leg to work extremely hard.