PURPOSE To investigate the effects of a demanding military field exercise on physical performance, body composition and muscle cellular outcomes in men and women. METHODS Ten men (20.5 ± 0.5 years) and 8 women (21.4 ± 1.4 years) completed a 10-day field exercise consisting of extensive physical activity with food and sleep restriction. Acquisition of body composition, physical performance, blood and muscle biopsies samples were done before and 1,7 and 14 days after the exercise. RESULTS There were no sex differences in the response to the exercise. Body mass was decreased with 5.6 ± 1.8% and fat mass with 31 ± 11% during the exercise. Both were still reduced after 14 days (2.5 ± 2.3%, p˂0.001 and 12.5 ± 7.7%, p˂0.001 respectively). Isometric leg strength did not change. Peak leg extension torque at 240 °·s-1 and counter movement jump height were reduced with 4.6 ± 4.8% (p = 0.012) and 6.7 ± 6.2% (p˂0.001) respectively and was still reduced after 14 days (4.3 ± 4.2%, p = 0.002, and 4.1 ± 4.7%, p = 0.030). No changes occurred in fiber CSA, fiber types, proteins involved in calcium handling or HSP70. During the exercise, αB-crystallin levels decreased by 14 ± 19% (p = 0.024) in the cytosolic fraction and staining intensity on muscle sections tended to increase (17 ± 25%, p = 0.076). MuRF1 levels in the cytosolic fraction tended to decrease (19 ± 35%) and increased with 85 ± 105% (p = 0.003) in the cytoskeletal fraction 1 week after the exercise. CONCLUSIONS The field exercise resulted in reduced body mass and physical performance in both sexes. The ability to produce force at high contraction velocities and explosive strength was more affected than isometric strength, but this was not related to any changes in fiber type composition, fiber area, Ca2+ handling or fiber type specific muscle damage.

中文翻译：

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为期 10 天的军事野外演习对男性和女性身体成分、身体表现和肌肉细胞的影响。

目的 调查高要求的军事野外演习对男性和女性身体表现、身体成分和肌肉细胞结果的影响。方法 10 名男性（20.5 ± 0.5 岁）和 8 名女性（21.4 ± 1.4 岁）完成了为期 10 天的野外演习，包括大量的体力活动以及限制饮食和睡眠。在运动前以及运动后 1,7 和 14 天采集身体成分、身体表现、血液和肌肉活检样本。结果 对运动的反应没有性别差异。运动期间体重减少了 5.6 ± 1.8%，脂肪量减少了 31 ± 11%。14 天后两者仍然减少（分别为 2.5 ± 2.3%，p˂0.001 和 12.5 ± 7.7%，p˂0.001）。等距腿部力量没有改变。240°·s-1 时的峰值腿部伸展扭矩和反向运动跳跃高度分别降低了 4.6 ± 4.8% (p = 0.012) 和 6.7 ± 6.2% (p˂0.001)，并且在 14 天后仍然降低 (4.3 ± 4.2) %，p = 0.002 和 4.1 ± 4.7%，p = 0.030）。纤维 CSA、纤维类型、参与钙处理的蛋白质或 HSP70 没有发生变化。运动期间，胞浆部分中的 αB-晶状体蛋白水平下降 14 ± 19% (p = 0.024)，肌肉切片的染色强度趋于增加 (17 ± 25%，p = 0.076)。运动后 1 周，细胞质部分中的 MuRF1 水平趋于下降 (19 ± 35%)，而细胞骨架部分中的 MuRF1 水平则增加 85 ± 105% (p = 0.003)。结论 野外锻炼导致男女体重和身体机能下降。在高收缩速度和爆发力下产生力量的能力比等长力量受到的影响更大，但这与纤维类型组成、纤维面积、Ca2+处理或纤维类型特定肌肉损伤的任何变化无关。