Effect of Exercise Training Programs on Physical Fitness Domains in Military Personnel: A Systematic Review and Meta-Analysis

Introduction: Physical training is important to prepare soldiers for the intense occupational demands in the military. However, current physical training may not address all fitness domains crucial for optimizing physical readiness and reducing musculoskeletal injury. The effects of nontraditional military physical training on fitness domains have been inconsistently reported, which limits the design of the ideal training program for performance optimization and injury prevention in the military. The aim of this systematic review was to identify the effects of exercise training on various fitness domains (i.e., aerobic fitness, flexibility, muscular endurance, muscular power, muscular strength, and occupationally specific physical performance) that contribute to occupational performance and musculoskeletal injury risk in military personnel. Methods: An extensive literature search was conducted in January 2021 and was subsequently updated in July 2021 and December 2021. Included studies consisted of comparative groups of healthy military personnel performing traditional and nontraditional military physical training with at least one assessment representative of a fitness domain. Study appraisal was conducted using the PEDro scale. Meta-analysis was conducted via forest plots, standard mean difference (SMD, effect size), and intertrial heterogeneity (I-2). Results: From a total of 7,350 records, 15 studies were identified as eligible for inclusion in this review, with a total of 1,613 participants. The average study quality via the PEDro score was good (5.3/10; range 4/10 to 6/10). Non-traditional military physical training resulted in greater posttraining values for muscular endurance (SMD= 0.46; P=.004; I-2 = 68%), power (SMD= 1.57; P <.0001; I-2 = 90%), strength via repetition maximum testing (SMD= 1.95; P <.00001; I-2 = 91%), and occupationally specific physical performance (SMD= 0.54; P=.007; I-2 = 66%) compared to the traditional group. There was no significant difference for aerobic fitness (SMD=-0.31; P=.23; I-2 = 86%), flexibility (SMD= 0.58; P=.16; I-2 = 76%), and muscular strength via maximal voluntary contraction (SMD= 0.18; P=.28; I-2 = 66%) between training groups. Conclusions: The current systematic review identified that nontraditional military physical training had a greater posttraining effect on muscular endurance, power, strength measured via repetition maximum, and occupationally specific physical performance compared to traditional military physical training. Overall, these findings suggest that nontraditional military physical training may be beneficial in optimizing occupational performance while potentially reducing musculoskeletal injury risk.