Article Title



Elizabeth L. Rogers1, Cassandra M. Beattie1, Katie M. Heinrich1, FACSM, Chunki Fong2, Christopher K. Haddock3, Walker S. C. Poston3

1Kansas State University, Manhattan, Kansas; 2The City University of New York, New York, New York; 3NDRI-USA, Leawood, Kansas

Peak performance depends on adequate sleep, yet only 37% of Army soldiers achieve the recommended 7-9 hours/night. Physical activity (PA) is associated with improved muscle strength and endurance; muscle strength correlates strongly with vigorous PA. Males are more likely to meet vigorous PA guidelines (31.6%), compared to females (26.0%). PURPOSE: This study aimed to identify if min/week of vigorous aerobic PA and strength training, sleep, and sex predicted soldiers’ fitness performance (i.e., 1-rep max deadlift, pull-up, horizontal jump, and dummy drag). We hypothesized that male sex and greater levels of sleep, vigorous PA, and strength training will predict better performance. METHODS: Data were from a 5-year cluster-randomized controlled trial. Participants (N = 119, 77.3% male) were active-duty military, National Guard, and Reserves personnel recruited to participate in 6-months of fitness training. At baseline, participants completed an online survey collecting moderate-vigorous aerobic PA min/week, strength training min/week, and accumulated hours of sleep/night. A 1-rep max deadlift, pull-ups, horizontal jump, and dummy drag test were also completed. Multiple linear regression analyses examined significant predictors for each fitness test. RESULTS: Vigorous PA and sleep were not significant predictors for any baseline measure. Over half the variance for deadlift weight (R2 = 0.544) was significantly predicted by strength training min/week (β = 0.276, p = 0.001) and sex (male; β = 0.640, p < 0.001). Pull-ups (R2 = 0.435) were significantly predicted by strength training min/week (β = 0.201, p = 0.024) and sex (male; β = 0.514, p < 0.001). Horizontal jump distance (R2 = 0.359) was significantly predicted by strength training min/week (β = 0.279, p = 0.003) and sex (male; β = 0.527, p < 0.001). Dummy drag time (R2 = 0.478) was significantly predicted by sex (male; β = -0.651, p < 0.001). CONCLUSION: Strength training and male sex were the best predictors for the fitness tests. Army policy surrounding physical fitness should consider prioritizing strength training more to improve performance in these fitness domains. Future research should examine changes in sleep and PA over time to determine how changes in each influence changes in fitness performance.

ACKNOWLEDGEMENTS: This study was supported by a grant from the National Institute of Diabetes and Digestive and Kidney Diseases awarded to Dr. Heinrich and Dr. Poston (R01DK099516).

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