Foot problems linked to stress fractures

Runners who have high arches or flat feet are more likely than others to suffer painful bone injuries of the leg or foot called stress fractures, a Mayo Clinic study shows.

On the other hand, people with these or other foot abnormalities don't appear to be at increased risk of running-related knee injuries, according to the study of Navy SEALs.

Those findings contradict some previous research that suggested common problems in runners' knees (including kneecap pain and pain on the side of the knee) could be traced to abnormal foot structure.

The results seem likely to be reliable because the participants -- 449 Navy SEAL trainees -- were young, healthy, in good shape, lived together under uniform conditions, and were monitored for injuries during an intensive training program that often included running up to 10 miles a day.

Mayo researchers carried out detailed studies of participants' foot and ankle structure, including measuring the height of their arches, the flexibility of their ankle joints, and the area of the mid-foot (the sole under the arch) that contacted the ground during walking -- both barefoot and in combat boots. Then they kept track of the frequency of several common overuse injuries, including stress fractures of bones of the foot or leg, aching around the kneecap, pain on the side of the knee, Achilles tendinitis (inflammation of the tendon just above the heel) and ''shin splints.''

A total of 149 participants -- 33 percent -- suffered at least one of these injuries during training. Stress fractures were the most common problem and were more frequent in trainees with either low or high arches.