Update: Exertional rhabdomyolysis, active component, U.S. Armed Forces, 2016-2020.

Among active component service members in 2020, there were 501 incident cases of exertional rhabdomyolysis, for an unadjusted incidence rate of 37.8 cases per 100,000 person-years (p-yrs). Subgroup-specific rates in 2020 were highest among males, those less than 20 years old, non-Hispanic Black service members, Marine Corps or Army members, and those in combatspecific occupations. During 2016-2020, crude rates of exertional rhabdomyolysis reached a peak of 42.9 per 100,000 p-yrs in 2018 after which the rate decreased to a low of 37.8 per 100,000 p-yrs in 2020. Most cases of exertional rhabdomyolysis were diagnosed at installations that support basic combat/ recruit training or major ground combat units of the Army or the Marine Corps. Medical care providers should consider exertional rhabdomyolysis in the differential diagnosis when service members (particularly recruits) present with muscular pain or swelling, limited range of motion, or the excretion of darkened urine after strenuous physical activity, especially in hot, humid weather.