Effect of On-Duty Resistance Training Fatigue on Neuromuscular Function in Structural Firefighters

Participation in on-duty exercise is critical to enhance firefighter safety and readiness. However, these sessions are often interrupted with emergency responses and require firefighters to work in a fatigued state that may increase injury risk.

To assess the impact of on-duty resistance training on neuromuscular function.

A sample of 18 firefighters (Age: 38.8 ± 8.0 y; Body fat: 24.9 ± 7.0%) completed three testing sessions, separated by at least 72 h to compare the effects of circuit (CT) versus heavy resistance training (HRT) fatigue on neuromuscular function. During Session 1, anthropometrics and familiarization trials of balance and neuromuscular function were completed, which included single-leg drop landing (SLDL), postural sway (PS), and modified Functional Balance Test (mFBT). Sessions 2 and 3 were randomized, where participants completed either HRT or CT. Isometric midthigh pull (IMTP), long jump (LJ), and lower body power (LBP) tests were conducted pre- and immediately post exercise, whereas static and dynamic balance assessments were conducted pre- and 10 min post exercise to simulate an emergency response time course. Repeated measures ANOVA, effect sizes, and difference scores were used to analyze the effects of condition and time. The level of significance was set at p < 0.05.

CT decreased IMTP, LJ, and LBP, whereas HRT decreased LJ and LBP (p ≤ 0.001, ES ≥ 0.476). Despite several significant condition by time interaction effects on balance outcomes, there were no differences within CT or HRT over time (p ≥ 0.066).

These findings suggest that on-duty resistance training reduces firefighters' power and/or strength immediately post exercise but does not influence most firefighters' balance 10 min post exercise. Thus, firefighters are recommended to perform resistance training on-duty during low emergency call volume times.