St. Gallen Health Center, St. Gallen, Switzerland.
Res Q Exerc Sport. 2009 Sep;80(3):593-603. doi: 10.1080/02701367.2009.10599598.
We investigated whether ultraendurance runners in a 100-km run suffer a decrease of body mass and whether this loss consists of fat mass, skeletal muscle mass, or total body water. Male ultrarunners were measured pre- and postrace to determine body mass, fat mass, and skeletal muscle mass by using the anthropometric method. In addition, bioelectrical impedance analysis was used to determine total body water, and urinary (urinary specific gravity) and hematological parameters (hematocrit and plasma sodium) were measured in order to determine hydration status. Body mass decreased by 1.6 kg (p < .01), fat mass by 0.4 kg (p < .01), and skeletal muscle mass by 0.7 kg (p < .01), whereas total body water increased by 0.8 L (p < .05). Hematocrit and plasma sodium decreased significantly (p < .01), whereas plasma urea and urinary specific gravity (USG) increased significantly (p < .01). The decrease of 2.2% body mass and a USG of 1.020 refer to a minimal dehydration. Our athletes seem to have been relatively overhydrated (increase in total body water and plasma sodium) and dehydrated (decrease in body mass and increase in USG) during the race, as evidenced by the increased total body water and the fact that plasma sodium and hematocrit were lower postrace than prerace. The change of body mass was associated with the change of total body water (p < .05), and we presume the development of.
我们研究了 100 公里长跑中超长跑运动员的体重是否会下降，以及这种体重减轻是否由脂肪质量、骨骼肌质量或总体水组成。我们通过人体测量法测量男性超长距离跑步运动员的比赛前后的体重、体脂和骨骼肌质量。此外，还使用生物电阻抗分析来确定总体水，测量尿液（尿比重）和血液学参数（红细胞压积和血浆钠）以确定水合状态。体重下降了 1.6 公斤（p<.01），体脂下降了 0.4 公斤（p<.01），骨骼肌质量下降了 0.7 公斤（p<.01），而总体水增加了 0.8 升（p<.05）。红细胞压积和血浆钠显著下降（p<.01），而血浆尿素和尿比重（USG）显著升高（p<.01）。体重下降 2.2%和 USG 为 1.020 表明存在轻微脱水。我们的运动员在比赛中似乎存在相对过度水合（总体水和血浆钠增加）和脱水（体重下降和 USG 增加）的情况，这可以从总体水的增加以及赛后血浆钠和红细胞压积低于赛前这一事实得到证明。体重变化与总体水变化相关（p<.05），我们推测是由于脱水导致体重下降。
