Reliability and Divergent Validity of Novel Tools to Assess Occupationally Relevant Performance in Infantry Soldiers.

Abstract

Abstract: Heilbronn, BE, Doma, K, Sinclair, WH, Drain, J, Connor, J, and Leicht, AS. Reliability and divergent validity of novel tools to assess occupationally relevant performance in infantry soldiers. J Strength Cond Res 39(6): e815-e823, 2025-The primary aim of this study was to determine the reliability and divergent validity of several weighted physical assessments for the Army, including the counter movement jump (CMJ), plyometric push-ups (PPU), an incremental fire and movement assessment (IMFA), and a repeated sprint ability (RSA) test. Male infantry soldiers ( n = 30) completed the CMJ, PPU, IFMA, and RSA during both unweighted and weighted conditions with a 48-hour interval between sessions, and then repeated the tests during a weighted condition after a 7-day wash-out period. Intraclass correlation coefficient (ICC) and coefficient of variation (CV) assessed between-session reliability. Divergent validity between weighted and unweighted conditions was determined using Pearson's correlation coefficient ( r ), with correlation effect size (ES) calculated between the r -values using a Fisher Z-transformation. Good test-retest reliability and divergent validity were demonstrated for most CMJ (ICC 0.50-0.99, CV% 1.18-7.73, ES 0.50-0.69), PPU (ICC 0.61-0.99, CV% 1.03-12.33, ES 0.31-0.68), RSA (ICC 0.50-0.94, CV% 1.34-8.41, ES 0.37-0.75), and IFMA (ICC 0.65-0.94, CV% 2.80-10.99, ES 0.32-0.39) measures. It was concluded that the weighted CMJ, PPU, IMFA, and RSA were reliable tests for Army-specific fitness to determine combat task readiness. Good divergent validity between weighted and unweighted conditions for most test measures supported practitioner's use of weighted assessments for Army-specific capability, while unweighted assessments were recommended for fitness optimization and monitoring training for Army personnel.