Altering the biomechanics of training and training schedules may reduce the prevalence of stress fractures.[9] Orthotic insoles have been found to decrease the rate of stress fractures in military recruits, but it is unclear whether this can be extrapolated to the general population or athletes.[10] On the other hand, some athletes have argued that cushioning in shoes actually causes more stress by reducing the body's natural shock-absorbing action, thus increasing the frequency of running injuries.[11] During exercise that applies more stress to the bones, it may help to increase daily calcium (2,000 mg) and vitamin D (800 IU) intake, depending on the individual.[9]