N: (0:02) Houston Waters INITIAL MILITARY TRAINING IS A PHYSICALLY DEMANDING ENVIRONMENT. IT SHOULD COME AS NO SURPRISE THAT MUSCULOSKELETAL INJURY, NAMELY STRESS FRACTURES, ARE THE NUMBER ONE CAUSE OF MEDICAL HOLDOVER.EXPERTS FROM THE U.S. ARMY RESEARCH INSTITUTE OF ENVIRONMENTAL MEDICINE'S MILITARY PERFORMANCE DIVISION HAVE BEEN HARD AT WORK DEVELOPING SOLUTIONS.SB: (0:22) Dr. Erin Gaffney-Stomberg, principal investigator, USARIEM "So this particular lab study follows directly from observations that we made during initial military training, identifying certain hormones that go up with training in the blood -- they may be related to how bones change with training.SB: (0:33) Jeff Staab, associate investigator, USARIEM We've chosen this task because it is very militarily relevant -- they're carrying a heavy load, a weighted vest, but we also wanted to make sure that we can see a change in the calcium and the associated hormones with the exercise task.N: (0:50) Houston Waters BY REPLICATING ASPECTS OF BASIC TRAINING, EXPERTS CAN EVALUATE HOW BONE HORMONE LEVELS IN THE BLOOD MAY BE RELATED TO HOW BONES RESPOND TO MILITARILY RELEVANT EXERCISE. USARIEM USES FEMALE VOLUNTEERS WITH NO PRIOR MILITARY EXPERIENCE.SB: (1:05) Anna Nakayama, project coordinator, USARIEM Women are four to five times more likely to have a stress fracture than men, and now that women are allowed in combat arms positions it's even more important to focus on women and see what's happening with stress fractures.N: (1:20) Houston Waters EVEN THOUGH THE STUDY UTILIZES ONLY FEMALE VOLUNTEERS, RESEARCHERS BELIEVE THE DATA COLLECTED WILL HAVE WIDESPREAD APPLICABILITY.SB: (1:28) Dr. Erin Gaffney-Stomberg, principal investigator, Military Performance Division, USARIEM While we're studying females specifically in this study, we anticipate we can use the results to help everyone going through initial military training. So generalize it really to all trainees.N: (1:41) Houston Waters DATA SUGGESTS ABOUT 60 PERCENT OF RECRUITS WITH STRESS FRACTURES END UP MEDICIALLY DISCHARGED FROM THE MILITARY. BY UNDERSTANDING THE ROLE OF EXERCISE AND NUTRITION ON BONE FORMATION, THE USARIEM STUDY HOPES TO REDUCE THAT NUMBER, STRENGTHEN THE FORCE, AND IMPROVE READINESS.FOR NATICK SOLDIER SYSTEMS CENTER, I'M HOUSTON WATERS.