According to the American Academy of Podiatric Sports Medicine, running places a tremendous amount of stress on your feet. AAPSM indicates that during a 10-mile run, the feet strike the ground approximately 15,000 times. This results in force that is three to four times greater than the body weight of a runner. Due to large amounts of stress placed on the feet, runners will sometimes experience an injury known as a stress fracture of the foot.
Metatarsal Stress Fractures
A stress fracture of the foot is commonly called a metatarsal stress fracture. The metatarsals are the long bones of your feet, with five located in each foot. According to Children's Memorial Hospital's Institute for Sports Medicine, 90 percent of foot stress fractures occur in the second, third and fourth metatarsals. The second metatarsal is most frequently affected. A stress fracture is a small break in a bone caused by repetitive stress placed on the bone, often as a result of running or jumping.
Risk Factors
Some individuals are more prone to developing stress fractures than others. If you rapidly increase your running regime, wear poor-fitting shoes and do not rest between workouts, you are more likely to develop a stress fracture. Other risk factors include changing your running surface -- such as grass to concrete -- or changing your running terrain -- running on a track to running hills. Flat feet; high arches; weak leg muscles; low bone density; and a family history of bone disease, such as osteoporosis, all increase the incidence of stress fractures in runners.
Symptoms and Treatment
The pain of a metatarsal stress fracture is often worse when running and may subside with rest. As the stress fracture progresses, runners may experience constant pain on the top of the foot. Swelling and bruising may also occur. A physical exam, X-ray and possible MRI are used to diagnose a stress fracture. Treatment may include rest, activity modification, anti-inflammatory medications, a walking boot and sometimes crutches. Treatment usually takes three to four weeks, according to Children's Memorial Hospital.
Prevention
There are a number of actions you can take to help prevent stress fractures of the foot. AAPSM recommends frequent runners visit with a podiatrist regularly to check for foot abnormalities and signs of stress on the feet. You should change your running shoes when they become worn or damaged. Other prevention methods include gradually increasing your training regime, allowing yourself to rest one to two days per week, staying physically fit and eating a healthy, well-balanced diet.
