some physical trainers, podiatrists, and shoe manufacturers) that a person with flat feet tends to overpronate in the running form. however, some also assert that persons with flat feet may have an underpronating if they are not a neutral gait. with standard running shoes, these professionals claim, a person who overpronates in his or her running form may be more susceptible to shin splints, back problems, and tendonitis in the knee. running in shoes with extra medial support or using special shoe inserts, orthoses, may help correct one's running form by reducing pronation and may reduce risk of injury. military performance studies analyzing the correlation between flat feet and physical injuries in soldiers have been inconclusive, but none suggest that flat feet are an impediment, at least in soldiers who reached the age of military recruitment without prior foot problems. a 2005 study of royal australian air force recruits that tracked the recruits over the course of their basic training found that neither flat feet nor high arched feet had any impact on physical capability, injury rates or bipedal aptitude. although there have been results rendered from military trials that have shown those with flat feet to have fewer injuries. no current studies have been successful in fully ascertaining the chronic, long-term detriments to health that are caused by the overexertion (of which is necessary for athletes/soldiers performing with flat feet) and other compensating measures commonly enacted by the body during bipedal movement. another divergent study of 295 israel defense forces recruits found that those with high arches had almost four times as many stress fractures as those with the lowest arches. a later study of 449 u.s. navy special warfare trainees found no significant difference in the incidence of stress fractures among sailors and marines with different arch heights.