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Purpose: To help evaluate the Army Physical Fitness Test (APFT) and ensure a future test is associated with Soldiers performance of common physical job requirements, the USAPHC applied a Systematic Review (SR) methodology to identify and synthesize published correlations between military task performance and physical fitness tests. Methods: A preliminary step to our SR was to identify key military-relevant tasks and physical fitness components of interest. Starting with the Army's Warrior Tasks and Battle Drills (WTBDs), twelve task categories were identified, including some tasks performed by both military and civilian occupations (e.g., firefighters, police, and athletes). Physical fitness tests were sorted into four physical fitness groups: cardiorespiratory endurance (e.g., aerobic fitness), muscle strength, muscle endurance, and flexibility. Tests of muscular strength and muscular endurance were further subcategorized into Upper and Lower Body, Core, or Whole Body regions. Physical tests included the APFT events (2-mile run, sit ups, push-ups) as well as other equipment and non-equipment physical fitness tests (e.g., jump tests, squats, sprints, pull-ups, grip tests, arm lifts, curls, and various extension machine tests). To synthesize the data, a series of meta-analyses provided pooled correlation coefficients for the twelve tasks and eleven physical fitness test groups. Results: Flexibility tests were the least frequently identified, while upper body strength tests were most frequently identified in studies that met our inclusion criteria. Correlations with aerobic tests were fairly well studied, with a few notable gaps (e.g., the Loaded March task). Pooled r coefficients for specific physical tests (e.g., run tests, push-ups, sit-ups, grip tests, and vertical and broad jump tests) were also calculated. Of the physical fitness component groups evaluated, aerobic capacity is most strongly correlated across the greatest number of military tasks., Public Health Report. The original document contains color images.

Sweating threshold temperature and sweating sensitivity responses are measured to evaluate thermoregulatory control. However, analytic approaches vary, and no standardized methodology has been validated. This study validated a simple and standardized method, segmented linear regression (SReg), for determination of sweating threshold temperature and sensitivity. Archived data were extracted for analysis from studies in which local arm sweat rate (m'sw; ventilated dew-point temperature sensor) and esophageal temperature (Tes) were measured under a variety of conditions. The relationship m'sw/Tes from 16 experiments was analyzed by seven experienced raters (Rater), using a variety of empirical methods, and compared against SReg for the determination of sweating threshold temperature and sweating sensitivity values. Individual interrater differences (n=324 comparisons) and differences between Rater and SReg (n=110 comparisons) were evaluated within the context of biologically important limits of magnitude (LOM) via a modified Bland-Altman approach. The average Rater and SReg outputs for threshold temperature and sensitivity were compared (n=16) using inferential statistics., Published in Journal Applied Physiology, v107 p69-75, 2009.

Background: Cold weather injuries (CWI) are of great military concern due to their wide-ranging impact on military readiness. Previous short-term studies have identified CWI to be more prevalent in African-Americans, infantrymen, and lower ranking soldiers. The purpose of this cross-sectional study was to determine the occurrence of CWI hospitalizations in the U.S. Army from 1980-1999, and to identify possible trends, high-risk groups and/or activities.

Acetazolarnide (AZ) can be taken at sea level (SL) to prevent acute mountain sickness during subsequent altitude (ALT) exposure. AZ causes metabolic acidosis at SL and ALT, and increases arterial oxygen saturation (SaO2) at ALT. HYPOTHESIS: AZ will impair muscle endurance at SL but not ALT (4300 m, <3 h). METHODS: Six subjects (2012 yr; Xl SD) performed exhaustive constant work rate 1-leg knee extension exercise (2512 watts) once per wk for 4 wks (2 wks at SL and 2 wks at ALT). Each week, subjects took either AZ (250 mg) or placebo orally (double blind) every 8 h starting one-day prior to exercise. All exercise bouts began 3 h after the last (i.e., 4th) dose and 2 bouts began 2 h after ALT exposure. RESULTS: AZ caused similar acidosis in the same subjects at SL and ALT, but muscle endurance was impaired only at SL. CONCLUSION: Lack of endurance impairment at ALT during AZ was likely due to offsetting secondary effects resulting from the acidosis (e.g., increased SaO2) that improved muscle oxygen delivery.

In order to simulate the expected environmental conditions in a submarine that has become disabled (i.e., loss of electrical power and subsequent inability to control temperature, humidity, and oxygen and carbon dioxide levels), a system was created to control the oxygen and carbon dioxide concentration of an environmental chamber. The study protocol called for a baseline testing period of ambient environmental conditions for 2 days (20 deg C, 50% RH, 20.93% O2, 0.04% CO2), followed by a 24-hour transition phase to the disabled conditions (4 deg C, 80% RH, 16.75% O2, 2.50% CO2), which where maintained for 5 days. Due to numerous design factors, the hypobaric chamber facility was chosen to conduct this study, since the facility met all of the needs of the study except for the ability to control oxygen and carbon dioxide levels, which none of the institute's chambers are normally capable of. Reduced oxygen content was achieved by displacement with nitrogen, and increased carbon dioxide content was achieved by injection of 100% carbon dioxide and metabolic carbon dioxide production. The oxygen and carbon dioxide content of the chamber was continually monitored and controlled by a custom designed software system. During the 5 day 'disabled' portion of the study, chamber conditions were as follows: temp 4.51 +/- 0.56 deg C; relative humidity 80.48 +/- 5.27% RH; oxygen 16.73 +/- 0.06% and carbon dioxide 2.49 +/- 0.04%. Variations in temperature, oxygen and carbon dioxide levels, as indicated by the standard deviation, were all within desired limits (+/- 1.0 deg C; +/- 0.10% concentration). Relative humidity was outside the desired limit of +/- 3.0% R.