Relationships Between Isometric Midthigh Pull, Body Mass, Countermovement Jump, Upper-Body Muscular Endurance, and Intermittent Running With Job Task Performance in Firefighter Trainees

ABSTRACT: Lockie, RG, Dawes, JJ, Campana, T, Kramer, J, Orr, RM, and Romero, M. Relationships between isometric midthigh pull, body mass, countermovement jump, upper-body muscular endurance, and intermittent running with job task performance in firefighter trainees. J Strength Cond Res 40(7): 815-821, 2026-Maximal strength is essential for firefighters but may be challenging to measure in this population because of time constraints, injury risk, and ability variations. The isometric midthigh pull (IMTP) could provide a safe and expedient strength measure. Retrospective analysis of data from 47 firefighter trainees (41 men, 6 women) was used to examine relationships between body mass, IMTP, and other general fitness tests (countermovement jump, hand release push-ups, and Yo-Yo Intermittent Recovery Test Level 1 YYIRT1) with job-specific tasks. In addition to the general fitness tests, trainees completed the job-specific tests of the 40-m, 100.5-kg manikin drag, 10.67-m ladder extension, and 5-lap stair climb wearing a 12.9-kg self-contained breathing apparatus while carrying a 24.9-kg, 30.5-m long hose pack. Pearson's correlations derived relationships between body mass, and general fitness and job-specific tests (p < 0.05). Stepwise regression derived predictive relationships between body mass and the general and job-specific fitness tests (p < 0.05). Body mass (r = -0.517), IMTP (r = -0.622), and YYIRT (r = -0.384) significantly correlated with the manikin drag. Body mass (r = -0.392) and IMTP (r = -0.560) significantly correlated with the ladder extension. The manikin drag was significantly predicted by IMTP, body mass, and YYIRT1, with ∼52% explained variance. The ladder extension was significantly predicted by the IMTP (∼30% explained variance). The stair climb had no significant relationships. Maximal strength is needed for the manikin drag and ladder extension and could be especially important for lighter firefighters to move absolute loads. The IMTP could help predict performance in firefighter job tasks, although other factors such as technique would be important.