Affiliations: Occupational Physiology Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
Note: [] The findings in this article are those of the authors and should not be construed as an official Department of the Army position or policy. Investigators adhered to AR 70-25 and USAMRDC Regulation 70-25 on Use of Volunteers in Research.
Abstract: Pre-placement screening for physically demanding jobs should result in better job performance and fewer injuries, if the test components reflect job demands. The purpose of this study was to determine how seven strength measures, three Army Physical Fitness Test (APFT) scores, and three physical descriptors relate to performance on two stretcher-carry tasks: 1) a repeated short-distance carry and 2) a continuous long-distance carry. Twelve men and 11 women completed both tasks with and without (hand-carry) a shoulder harness. Pearson product moment correlation coefficients compared independent variables and forward stepwise multiple regression analyses were used for predictions. For repeated short distance stretcher-carrying, two-mile run time and handgrip were the best predictors of performance (hand-carry: r2=0.79, p<0.01; harness-carry: r2=0.75, p<0.01). The grip, which was more predictive during the hand-carry, required a sudden maximal contraction to peak force, followed by immediate release, while a sudden maximal contraction to peak force maintained for four seconds, was more predictive of the harness-carry. For the continuous hand-carry, the best predictor was a gradual buildup to a 6-second sustained grip strength (r2=0.74, p<0.01). These results illustrate the necessity for tailoring preplacement tests to accurately reflect job demands.
