Changes in Physical Performance Following Operational Military Training: A Meta-Analysis.

Background: To best simulate armed combat-related emergencies, military personnel undergo operational training that attempts to recreate multiple physical stressors. Understanding the specific aspects of physical performance degradation after operational training helps to better inform future training practices, as these declines translate to real-world operations. The purpose of this meta-analysis was to investigate the effects of operational trainings on physical performance metrics in military personnel.

Methods: Six electronic databases were searched for studies that investigated physical performance metrics in active-duty military personnel before and after multiple-day operational training. Sample sizes, means and standard deviations were extracted from included studies, and random-effects meta-analyses were conducted using standardized mean differences (Hedge's g) with 95% confidence intervals (p ≤ 0.05).

Results: Seventeen studies (N = 1592 participants) were included for final review and grouped by physical performance metric. Meta-analyses revealed a large pre-to-post decline in lower body jump power (n = 4, g = 0.87, 95% CI [0.28, 1.47]), and small declines in short-duration lower body power-jump distance (n = 5, g = 0.39, 95% CI [0.16, 0.63]), upper body endurance (n = 4, g = 0.40, 95% CI [0.09, 0.71]), and core endurance (n = 2, g = 0.46, 95% CI [0.10, 0.82]). Substantial heterogeneity was observed in the included studies (I² = 0-91%).

Conclusions: Military operational training temporarily diminishes lower body performance to a greater extent than other constructs. The most consistent findings showed reductions in power production (large magnitude) and muscular endurance (small magnitude), which appear to have implications for military training and risk reduction. In real-world operational applications, reduced power- and endurance-generating capabilities may be detrimental to meeting tactical requirements, making these metrics valuable for military leadership to focus on during personnel training.