Sex Differences in Training Loads during British Army Basic Training

Purpose To compare training loads between men and women during 14 wk of British Army standard entry basic training. Methods Thirty-one male (mean SD: age, 21 4 yr; height, 1.78 +/- 0.08 m; mass, 77.1 +/- 10.5 kg) and 28 female (age, 22 +/- 4 yr; height, 1.65 +/- 0.05 m; mass, 63.9 +/- 8.9 kg) British Army recruits had external (distance) and internal (HR, training impulse [TRIMP], RPE) training loads measured during weeks 1, 2, 6, 12, and 13 of basic training. Total energy expenditure was measured during weeks 1 to 2 and weeks 12 to 13. Results Daily distance was higher for men than women (13,508 +/- 666 vs 11,866 +/- 491 m, respectively, P < 0.001). Average daily HR (29% +/- 3% vs 30% +/- 3% HR reserve) and RPE (4 +/- 1 vs 4 +/- 1) were not different between men and women, respectively (P 0.495). Daily TRIMP was higher for women than men (492 +/- 130 vs 261 +/- 145 au, respectively, P < 0.001). Total energy expenditure was higher for men than women during weeks 1 to 2 (4020 +/- 620 vs 2847 +/- 323 kcal d( -1), respectively) and weeks 12 to 13 (4253 +/- 556 kcal d( -1) vs 3390 +/- 344 kcal d( -1), respectively) (P < 0.001). Daily RPE, HR, and TRIMP were related to daily distance (R-2 = 0.18-0.57, P 0.037), and daily RPE was related to daily TRIMP and HR (R-2 = 0.37-0.77, P 0.001). Conclusions Sex differences in training loads could contribute to the greater injury risk for women during basic training. Daily RPE appears a practical option for measuring internal training load during military training.