The Skeletal System is an amazing feat of biologic engineering! Unfortunately, like many other structures, it is also prone to breakdown and mechanical failure. Stress fractures are an unfortunate reality in the world of endurance sports, especially in the lower extremities of runners. Running can result in forces applied to the bone and joints in excess of 6-8 times an athletes body weight. Over extended periods of time, and without proper recovery between workouts, these forces can result in stress fractures, most commonly in the pelvis, leg, and foot.