Hepler, Timothy Caleb2021-04-062021-04-062021-05-01https://hdl.handle.net/2097/41327Physical fitness and performance measures are predictive of Special Forces Assessment and Selection and performance during combat-specific tasks. In combat, approximately 50% of casualties are lost to direct-fire engagements, which requires resiliency to fatigue during repeated high-intensity sprints (under combat load) and delivering suppressive fire while under duress. Currently, the US Army does not have a physical fitness test that is predictive of combat survival. This study examined the predictive ability of field-expedient physical fitness/performance tests on a simulated military task (SMT) that mimicked a direct-fire engagement. Healthy subjects (N = 39, age = 25.3 ± 6.8 years) completed upper- and lower-body strength (i.e., handgrip, isometric midthigh clean pull) and power (i.e., seated power throw, standing broad jump) tests and a 3-minute all-out running test to determine critical velocity. Subjects returned to the laboratory to complete a simulated military task (SMT) that consisted of marksmanship with cognitive workload assessment (CWL) and a fire-and-move simulation (16 6-m bounds) while wearing a vest simulating a combat load (25-kg). Susceptibility to enemy fire was modeled on bound duration during the fire-and-move simulation. Stepwise linear regression identified predictors for the tactical combat movement simulation components. Significant regression models were identified for both susceptibility to enemy fire (R² = 0.755, p < 0.001) and cognitive performance (R² = 0.162, p < 0.05). Critical velocity predicted both susceptibility to enemy fire (β = 0.40, p < 0.01) and cognitive performance (β = -0.30, p < 0.05), and standing broad jump predicted susceptibility to enemy fire (β = -7.20, p < 0.001). All variables demonstrated poor relationships with marksmanship accuracy (r = -0.03-0.24, ps > 0.05) and no statistically significant regression model was identified. These data demonstrate the importance of exercise tolerance (i.e., critical velocity) and lower-body power (standing broad jump) in performance during a simulated direct-fire engagement and provide potential targets for interventions to monitor and enhance performance and support soldier resiliency.en-US© the author. This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).http://rightsstatements.org/vocab/InC/1.0/MarksmanshipCombat survivabilitySusceptibility to enemy fireCognitive performanceCritical velocityThesis