In most cases, the risk of muscle and bone injury during exercise in a person with diabetes is similar to that of someone without diabetes. However, those who do not have good control of their glucose or who have long-standing diabetes may develop nerve damage that affects the muscles. For example, claw-foot deformity is a condition that is seen in those who lose function of nerves that supply the muscles to the feet. This leads to deformity of the feet, in which the toes are clenched to resemble a claw.