Abstract
BACKGROUND: Low baseline fitness of recruits entering basic military training (BMT) is associated with an increased risk of musculoskeletal injuries (MSIs) and attrition from training. OBJECTIVE: To determine the effects of a pre-training conditioning program (PCP) on aerobic endurance, incidence of musculoskeletal injuries (MSIs), and attrition rates in BMT of a special infantry unit of the Netherlands Armed Forces. PARTICIPANTS: Recruits were considered eligible for this study when they were 'low-fit' at the start of BMT (time to complete a 2.7-km run ≥ 12'23″). INTERVENTIONS: 'Low-fit' recruits were deferred to a seven to twelve week-depending on the time between two consecutive training platoons-PCP consisting of functional training to improve several fitness domains. The control (CON) group started regular BMT without delay. RESULTS: Forty-nine recruits were included in this study; 26 in the PCP-group and 23 in the CON-group. Recruits who followed the PCP started BMT with better aerobic endurance than the CON-group who started BMT immediately (2.7 km run timings: PCP 11'32″, CON 13'16″). The risk of dropout was lower in the PCP-group (incidence density ratio (IDR) 0.63, 95%CI 0.32; 1.26), but dropout due to training-related MSIs was more frequent (IDR 1.23, 95%CI 0.32; 4.76 (per-protocol 0.94, 95%CI 0.24; 3.63), without statistically significant differences between the groups. CONCLUSION: Although a PCP was effective to improve aerobic endurance in low-fit recruits to return to meet pre-enlistment fitness criteria, we could not demonstrate an effect on dropout from military training. TRIAL REGISTRATION: Dutch trial register Trial NL6791 (NTR6977) https://www.trialregister.nl/trial/6791.