Ojanen Tommi, Häkkinen Keijo, Vasankari Tommi, Kyröläinen Heikki
Finnish Defence Research Agency, Finnish Defence Forces, P.O. Box 5, 04401 Järvenpää, Finland.
Biology of Physical Activity, Faculty of Sport and Health Sciences, University of Jyväskylä, P.O. Box 35, 40014 Jyväskylä, Finland.
Mil Med. 2018 May 1;183(5-6):e174-e181. doi: 10.1093/milmed/usx049.
Few studies have reported the amount of physical activity (PA) and its associations to physical performance of warfighters during military field training (MFT). The purpose of this study was to investigate changes in neuromuscular performance and PA among male Finnish Army conscripts during a 21-d MFT and to evaluate their recovery during 4 d after MFT.
Body composition and physical performance were measured four times during the study (before MFT (PRE), after 12 d (MID), post training (POST) and after 4 d of recovery (RECO)). PA was measured throughout MFT in a group of healthy young male conscripts (n=49) by using a tri-axial accelerometer. The study was approved by the Finnish Defence Forces and was granted ethics approval by the Ethics Committee of the University of Jyväskylä.
Body mass declined significantly from 73.5 ± 8.7 to 71.6 ± 8.2 kg, but it recovered close to the PRE values (73.0 ± 8.3 kg). The same trend was also found in skeletal muscle mass and fat mass. The change in body mass and in skeletal muscle mass correlated negatively with the change in vigorous physical activity (r = -0.374, p = 0.016, and r = -0.337, p = 0.031, respectively). Muscular endurance decreased significantly (p < 0.001) in sit-ups from the PRE (46 ± 9 reps/min) values compared with MID (40 ± 8 reps/min), POST (42 ± 8 reps/min), and RECO (34 ± 11 reps/min) values. Also in push-ups, the declines in the POST (34 ± 10 reps/min) and RECO (34 ± 13 reps/min) values (p < 0.001) from the PRE (40 ± 13 reps/min) and MID (39 ± 12 reps/min) values were observed. There was a significant decrease in a standing long jump in all measurement points MID (220 ± 20 cm), POST (216 ± 20 cm), and RECO (213 ± 20 cm) as compared with the PRE values (229 ± 23 cm, p < 0.001). There was no change in 3.2 km loaded march time between the PRE (23:57 ± 4:12 min:s) and POST (23:44 ± 5:02 min:s) measurement time points. In PA, the total number of steps per day was significantly (p < 0.001) greater during ST (13,722 ± 2,379 steps) and MFT (13,937 ± 2,276 steps) than during garrison days (9,550 ± 2,569 steps). In POST, there was significantly (p < 0.001) more light (1.5-3.0 metabolic equivalent) (2:34:38 ± 0:22:53 h:min:s in ST and 3:03:27 ± 0:23:24 h:min:s in MFT) and moderate (3.0-6.0 metabolic equivalent) (2:12:15 ± 0:23:14 h:min:s in ST and 2:47:59 ± 0:27:23 h:min:s in MFT) PA than in the PRE measurements.
This study demonstrated slight decrements in warfighter physical performance during the 21-d MFT. The conscripts were overloaded during MFT, but 4 d of recovery seemed not to be enough to obtain the PRE measurement values in physical performance. This study also showed changes in the muscular endurance levels and PA during the 21-d MFT. It is important for warfighters to have a good physical fitness level PRE training or combat. As the prolonged MFT may have adverse effects in warfighters muscular endurance and PA levels, it is important to have sufficient recovery time after long MFT to regain combat readiness.
很少有研究报告军事野外训练（MFT）期间战士的身体活动（PA）量及其与身体表现的关联。本研究的目的是调查芬兰男性陆军新兵在为期21天的MFT期间神经肌肉表现和PA的变化，并评估他们在MFT后4天的恢复情况。
在研究期间（MFT前（PRE）、12天后（MID）、训练后（POST）和恢复4天后（RECO））对身体成分和身体表现进行了四次测量。通过使用三轴加速度计对一组健康年轻男性新兵（n = 49）在整个MFT期间的PA进行测量。该研究得到了芬兰国防军的批准，并获得了于韦斯屈莱大学伦理委员会的伦理批准。
体重从73.5±8.7显著下降至71.6±8.2 kg，但恢复到接近PRE值（73.0±8.3 kg）。骨骼肌质量和脂肪质量也呈现相同趋势。体重和骨骼肌质量的变化与剧烈身体活动的变化呈负相关（分别为r = -0.374，p = 0.016和r = -0.337，p = 0.031）。与PRE（46±9次/分钟）相比，仰卧起坐的肌肉耐力在MID（40±8次/分钟）、POST（42±8次/分钟）和RECO（34±11次/分钟）时显著下降（p < ）。俯卧撑方面，与PRE（40±13次/分钟）和MID（39±12次/分钟）相比，POST（34±10次/分钟）和RECO（34±13次/分钟）时的值也显著下降（p < ）。与PRE值（229±23 cm）相比，所有测量点MID（220±20 cm）、POST（216±20 cm）和RECO（213±20 cm）的立定跳远均显著下降（p < ）。PRE（23:57±4:12分钟:秒）和POST（测量时间点之间的3.2公里负重行军时间没有变化（23:44±5:02分钟:秒）。在PA方面，ST（13,722±2,379步）和MFT（13,937±2,276步）期间每天的总步数显著多于驻防日（9,550±2,569步）（p < ）。在POST时，与PRE测量相比，有显著更多的轻度（1.5 - 3.0代谢当量）（ST为2:34:38±0:22:53小时:分钟:秒，MFT为3:03:27±0:23:24小时:分钟:秒）和中度（3.0 - 6.0代谢当量）（ST为2:12:15±0:23:14小时:分钟:秒，MFT为2:47:59±0:27:23小时:分钟:秒）PA（p < ）。
本研究表明在为期21天的MFT期间战士的身体表现略有下降。新兵在MFT期间负荷过重，但4天的恢复似乎不足以使身体表现恢复到PRE测量值。本研究还显示了在为期21天的MFT期间肌肉耐力水平和PA的变化。对于战士来说，在训练或战斗前拥有良好的身体素质水平很重要。由于长时间的MFT可能对战士的肌肉耐力和PA水平产生不利影响，在长时间的MFT后有足够的恢复时间以恢复战斗准备状态很重要。
