Decreased human circadian pacemaker influence after 100 days in space: a case study.

Objective: The objectives of this study were (1) to assess the circadian rhythms and sleep of a healthy, 42-year-old male astronaut experiencing microgravity (weightlessness) for nearly 5 months while living aboard Space Station Mir as it orbited Earth and (2) to determine the effects of prolonged space flight on the endogenous circadian pacemaker, as indicated by oral temperature and subjective alertness rhythms, and their ramifications for sleep, alertness, and performance.

Methods: For three 12- to 14-day blocks of time (spread throughout the mission), oral temperatures were taken and subjective alertness was self-rated five times per day. Sleep diaries and performance tests were also completed daily during each block.

Profiles of exercise history and overuse injuries among United States Navy Sea, Air, and Land (SEAL) recruits.

This prospective study examined running history as a risk factor for subsequent overuse injury in Navy Sea, Air, and Land (SEAL) recruits. Recruits preparing to be Navy SEALs undergo 6 months of rigorous physical training programs, which place these recruits at high risk for developing an overuse injury. We assessed the independent variables of age; prior running frequency, duration, and pace; and training surface.

Epidemiology of soft-tissue/musculoskeletal injury among U.S. Marine recruits undergoing basic training.

We determined the incidence of soft-tissue/musculoskeletal injury occurring during 8,076 recruit-months at risk among recruits undergoing basic training at Marine Corps Recruit Depot, San Diego, California, between January and April 1990. We analyzed International Classification of Disease codes relating to initial visit for injuries, and calculated recruit-months from weekly strength figures. Training-related injuries occurred at a rate of 19.

Epidemiology of podiatric injuries in US Marine recruits undergoing basic training.

The authors determined the incidence of podiatric injuries that occurred during 233,946 recruit days at risk among US Marine Corps recruits undergoing basic training at the Marine Corps Recruit Depot, San Diego, CA, between February 5 and April 25, 1990. Training-related initial injuries to the foot occurred at a rate of 3.0 new injuries per 1,000 recruit days.