Physiological, Physical, and Psychological Determinants of Success During the Naval Special Warfare Screener Selection Course

Abstract

Martin, BJ, Wright, M, Patel, V, Susmarski, A, Lovalekar, M, Forse, JN, Beckner, ME, Ledford, AK, and Nindl, BC. Physiological, physical, and psychological determinants of success during the naval special warfare screener selection course. J Strength Cond Res XX(X): 000-000, 2024-The Naval Special Warfare (NSW) screener is an arduous, 24-h course conducted at the Naval Academy in Midshipmen aspiring to enter the Navy's Sea, Air, and Land program. The purpose was to assess and characterize the physiological stress imposed during the 24-hour screener and identify physical, physiological, and psychological differences between finishers and nonfinishers. Forty-eight male Midshipmen between the ages of 18 and 26 years (height = 177.5 ± 6.8 cm, mass = 77.0 ± 5.3 kg, percent body fat = 7.54 ± 2.7%) participated. Before 4-6 weeks of the screener, subjects performed a battery of physical measures, questionnaires, and a cold pressor test (CPT). Blood was collected at baseline, post-CPT, and pre- and postscreener to assess the effects of the screener and differences between finishers and nonfinishers. A total of 48 Midshipmen started the screener, 37 finishers and 11 nonfinishers. Logistic regression revealed that 4 measures significantly increased the likelihood of finishing. A higher likelihood of finishing the screener was observed with Midshipmen with greater height (∼5 cm, p = 0.036), higher anaerobic power (∼0.5 W·kg-1, p = 0.036), greater low-back endurance (∼17 s, p = 0.039), and faster swim times (∼1 minute, p = 0.001). Dehydroepiandrosterone (DHEA) and serum cortisol were both lower after the CPT in finishers (p = 0.042 and 0.004, respectively) but were not different in nonfinishers. Dehydroepiandrosterone and the DHEA:salivary cortisol ratio were lower postscreener in finishers vs. nonfinishers (-70% and -133%, p = 0.008 and 0.001, respectively). In conclusion, this study presents novel findings regarding differences between finishers and nonfinishers of the NSW screener and how a 24-h event of particularly intense stressors affects biomarkers in a select group of Naval Academy Midshipmen.