Effects of Sex Hormone Suppression and Replacement on Muscle, Tendon, and Bone Health During Multi-Stressor Military Training in Adults Aged 18 to 40

What this Trial Is About

Non-combat-related muscle, tendon, and bone injuries are common among military personnel, especially new recruits, affecting readiness and causing significant medical costs. This research investigates how hormonal changes, specifically sex hormones like testosterone and estrogen, influence muscle, tendon, and bone function as well as physical and psychological performance under stress. The study aims to improve military physical training and reduce injuries by understanding these hormonal effects. Participants will be assigned to different groups including a control group maintaining normal habits and a stress exposure group undergoing a 4-week military-style physical training program. Some men and women in the stress group will receive medications to suppress natural hormone production and then receive hormone replacement or a placebo. Treatments include a GnRH agonist injection and topical testosterone gels or estrogenprogesterone patches, with dosing varying by group and sex. Throughout the approximately 8-week study, participants will undergo measurements such as muscle and tendon imaging, body composition analysis, blood tests for hormone and biochemical markers, and physical and mental performance evaluations. Researchers will monitor changes in these outcomes over time to assess the effects of hormone suppression and replacement on musculoskeletal resilience and adaptation to stress.

Adaptions and Resiliency to Multi-Stressor OpeRations