Christine Scott

Project title: Survival of the Fittest: Does Performance on a Pre-Employment Fitness Test Predict Injury in Army Job Training?

Degree: MPH | Program: Occupational Medicine (Occ Med) | Project type: Thesis/Dissertation
Completed in: 2005 | Faculty advisor: Matthew C. Keifer


Background: There is a high rate of injury in Army Basic Combat Training. Low physical fitness is a known risk factor for injury in basic training, so the ARMS (Assessment of Recruit Motivation and Strength) study was implemented at Military Entrance Processing Stations (MEPS) to assess physical fitness and motivation prior to enlisting.

Hypothesis: To determine if lower fitness level, as determined by the ARMS physical assessment test being performed at the MEPS, results in increased injury rate during Army initial job training.

Methods: This study was a prospective cohort design whose data collection was from the previously approved protocol titled Assessment of Recruit Motivation and Strength (ARMS) from Walter Reed Army Institute of Research. Data collection began April 2004. The cohort of 4363 recruits were men and women, ages 17-40 years, who successfully completed the MEPS process and administered the ARMS test from 1 April through 9 August 2004 and subsequently sent to their respective training sites. The cohort was followed for injuries and discharges through 9 December 2004. Seven large MEPS sites performed the ARMS fitness test on all individuals who entered the US Army. The ARMS is a battery of three tests which includes 1) modified Harvard Step test (measures aerobic fitness), 2) Incremental Dynamic Lift (IDL) (measures upper body strength) and 3) number of push-ups in 1 minute (measures upper body endurance).

Results: Aerobic fitness, defined as finishing or not finishing the 5 minute step test, was found to be deficient in 12% of the males and 20% of females. Likelihood of injury was significantly related to performance on the ARMS step test. Using the Cox proportional hazard model controlling for age, gender, and tobacco use, the risk for injury among men and women who were not able to finish the step test compared to those who successfully completed the step test was 1.38 (95% CI 1.17, 1.60; p(<0.001) and 1.34 (95% CI 1.07, 1.67; p=0.009), respectively.

Conclusion: The ability to finish a pre-employment 5 minute step test appears to be a useful predictor of risk of subsequent injury in Army initial job training.