Dimensionality Reduction Differentiates Sensitive Force-Time Characteristics from Loaded and Unloaded Conditions throughout Competitive Military Training

The purpose was to evaluate neuromuscular fatigue’s effect on unloaded and loaded countermovement jump (CMJ) force-time characteristics during high-intensity tactical training. Eighteen male sixteen female Marines completed two maximal effort CMJs, in (PVC pipe) (10 kg weight vest 20 barbell) conditions, prior to, 24, 48, 72 h after starting the 4-day event. top three variables from principal components (PC) were analyzed using mixed-effects modeling (PC1—concentric mean power, eccentric peak force, modified reactive strength index; PC2—countermovement depth, velocity; PC3—braking duration, height, power). Metrics PC1 PC3 reduced across training both loading conditions. PC2 similarly affected by external but less influenced training-induced fatigue. Jump performances with barbell shallower depths did not change throughout Thus, CMJs are stable measures suitable for tracking chronic adaptations. Monitoring 10 CMJ performances, along movement strategies (i.e., rates depth), may help identify moments of accumulated fatigue inform recovery adjustments improve sustainability personnel.