RESUMO
INTRODUCTION: Optimizing training load (TL) and sleep is essential to maximize physical performance and prevent musculoskeletal injuries (MSKIs) for Canadian forces recruits during the 10-week basic military qualification (BMQ) course. The purpose of this study was to assess the TL, sleep duration, the occurrence of MSKIs during the BMQ, and the operation fitness performance during the BMQ. MATERIALS AND METHODS: Forty Canadian recruits, eight females and 32 males, (age 24 ± 5 years; height 176.4 ± 10.4 cm), were monitored with an accelerometer (GENEActiv) on their wrist between weeks 1 and 9 to evaluate the TL and sleep duration. During weeks 2 and 10, the recruits completed an operational fitness evaluation. Injury surveillance was performed over 10 weeks. RESULTS: TL intensity was significantly different (P = 0.0001) from week to week. The weekly average total time of moderate and vigorous physical activity was 189.7 ± 48.1 min and 44.7 ± 15.2 min, respectively. The average sleep duration was 5.4 ± 0.4 h per night and decreased to 4.2 h ± 0.4 during field exercises. A significant difference in sleep duration was observed between recruits with and without a MSKI. The recruits accumulated a total of 95 days under medical restrictions with an average of 3.8 consecutive days. The VO2peak estimated from the Fitness for Operational Requirements of Canadian Armed Forces Employment job-based simulation test significantly improved from weeks 2 to 10 (pre, 47.1 ± 6.3; post: 50.2 ± 5.8; P = 0.001). CONCLUSIONS: TL is of high magnitude and varies from week to week. The reported mean sleep duration per week may perhaps negatively impact the occurrence of MSKI. No significant improvement was detected in operational fitness by the end of the BMQ.
RESUMO
INTRODUCTION: Musculoskeletal injuries (MSKIs) and recruitment are major challenges faced by modern military forces. The Canadian Armed Forces uses a physical employment standard (PES) proxy to determine occupational fitness and job suitability. It is unknown whether the performance on the PES proxy can be also used as predictor of MSKIs. The purpose of this study was to investigate for relationships between age, sex, body composition, aerobic fitness, performance on the Canadian Armed Forces PES proxy (FORCE evaluation), and risk of sustaining a MSKI requiring intervention in the Training Rehabilitation Program (MSKI-TRP1) during Canadian Basic Military Qualification. MATERIALS AND METHODS: This was a retrospective analysis of MSKIs in recruits introduced in the Training Rehabilitation Program (TRP1) in 2016 and 2017. A two-tailed t-test and a multivariate stepwise logistic regression were completed to investigate the interrelationships of sex, age, FORCE performance (20 m rushes, sandbag lift, intermittent loaded shuttles, sandbag drag) and health-related characteristics (waist circumference, predicted peak oxygen consumption [$\dot{V}$O2peak]), and odds for sustaining a MSKI-TRP. RESULTS: The MSKI-TRP1 intervention rate observed was 4.3%. Rehabilitation duration was an average (SD) of 87 (76) days; nearly 80% of MSKI-TRP were lower body injuries. MSKI-TRP recruits were older, had a lower score on FORCE, and had a larger mean waist circumference and lower $\dot{V}$O2peak than non-TRP1 recruits (all P < 0.01). Recruits with performance lower than 1 SD below mean on the 20 m rushes, intermittent loaded shuttle, or sandbag drag were 2.69 (1.89-3.83), 2.74 (1.91-3.95), and 2.26 (1.52-3.37) times more likely to sustain a MSKI-TRP1, respectively (all P < 0.01). Recruits with $\dot{V}$O2peak lower than 1 SD below mean were also 2.19 (1.30-3.70) times more likely to sustain a MSKI-TRP. Neither sex, age, nor waist circumference impacted the risk of MSKI-TRP1 when controlling for FORCE performance. CONCLUSIONS: The Canadian Armed Forces PES proxy performance can be used to assess the odds of sustaining a MSKI-TRP1 in Canadian military recruit training.