immediate risk of stress fracture) and on the long-term risk of osteoporosis. In so doing, the subcommittee was asked to respond to the following five questions:
In considering the questions posed by the military (and as a follow-on activity to the subcommittee's earlier report, Assessing Readiness in Military Women [IOM, 1998]), the subcommittee consulted with a liaison panel comprising military researchers and health care personnel. The BCNH subcommittee met in executive session following the workshop to begin drafting their brief report. The subcommittee met in executive session for an additional writing session and to discuss their conclusions and recommendations on January 27, 1998. Based on information gathered from discussion with the workshop speakers, the military liaison panel and a brief review of the literature on bone metabolism and risk factors for bone health, the subcommittee prepared this brief report, Reducing Stress Fractures in Physically Active Military Women . The report was submitted to the sponsor in June, 1998.
Low initial fitness of recruits appears to be the principal factor in the development of stress fractures during basic training. The basic training period may be insufficient time to achieve the aerobic fitness level required and the musculoskeletal adaptations necessary to avoid injury.
Muscle mass, strength, and resistance to fatigue with cyclic loading (bone stress created by rapid or excessive incremental skeletal muscle contraction and loading forces) play a critical role in the development of stress fracture. The etiology of stress fracture is multifactorial, and bone mineral density is only one contributing factor. Genetics and body mass, specifically muscle mass, are also important determinants of stress fracture.