Institute of Exercise Biology and Physiotherapy, Centre of Behavioural and Health Sciences, University of Tartu, Tartu, Estonia.
J Sports Sci Med. 2008 Jun 1;7(2):210-7. eCollection 2008.
The purpose of the study was to assess the acute effects of the self-selected regimen of rapid body mass loss (RBML) on muscle performance and metabolic response to exercise in combat sports athletes. Seventeen male athletes (20.8 ± 1.0 years; mean ± SD) reduced their body mass by 5.1 ± 1.1% within 3 days. The RBML was achieved by a gradual reduction of energy and fluid intake and mild sauna procedures. A battery of tests was performed before (Test 1) and immediately after (Test 2) RBML. The test battery included the measurement of the peak torque of knee extensors for three different speeds, assessment of total work (Wtot) performed during a 3-min intermittent intensity knee extension exercise and measurements of blood metabolites (ammonia, lactate, glucose and urea). Absolute peak torque was lower in Test 2 compared with Test 1 at angular velocities of 1.57 rad·s(-1) (218.6 ± 40.9 vs. 234.4 ± 42.2 N·m; p = 0.013) and 3.14 rad·s(-1) (100.3 ± 27.8 vs. 111.7 ± 26.2 N·m; p = 0.008). The peak torque in relation to body mass remained unchanged for any speed. Absolute Wtot was lower in Test 2 compared with Test 1 (6359 ± 2326 vs. 7452 ± 3080 J; p = 0.003) as well as Wtot in relation to body mass (89.1 ± 29.9 vs. 98.6 ± 36.4 J·kg(-1); p = 0.034), respectively. As a result of RBML, plasma urea concentration increased from 4.9 to 5.9 mmol·l(-1) (p = 0.003). The concentration of ammonia in a post-test sample in Test 2 tended to be higher in comparison with Test 1 (80.9 ± 29.1 vs. 67.6 ± 26.5 mmol·l(-1); p = 0.082). The plasma lactate and glucose responses to exercise were similar in Test 1 and Test 2. We conclude that the self-selected regimen of RBML impairs muscle performance in 3-min intermittent intensity exercise and induces an increase in blood urea concentration in experienced male combat sports athletes. Key pointsPrevious studies have revealed a negative effect of rapid body mass loss on performance. However, there are some performance characteristics that may not change or even improve.The methods used for inducing rapid body mass loss have been prescribed by researchers and not chosen by the subjects in many previous studies. The duration of tests, which have revealed a negative impact of rapid body mass loss on performance have also been rather long (5-6 min) in previous studies.We assessed the acute effects of the self-selected regimen of rapid body mass loss on muscle performance and metabolic response to 3-min intermittent intensity exercise in experienced male combat sports athletes.The results suggest that the self-selected regimen of rapid body mass loss impairs muscle performance in 3-min intermittent intensity exercise and induces an increase in blood urea concentration. Hence, the recent changes in the rules of some events (wrestling), including shortening of the duration of a match, have not reduced the likelihood of the occurrence of a negative impact of rapid body mass loss on athletes' performance capacity.
本研究旨在评估自选快速体重减轻（RBML）方案对搏击运动员肌肉性能和运动代谢反应的急性影响。17 名男性运动员（20.8±1.0 岁；均值±标准差）在 3 天内将体重减轻 5.1±1.1%。RBML 通过逐渐减少能量和液体摄入以及轻度桑拿程序来实现。在 RBML 前后（测试 1 和测试 2）进行了一系列测试。测试包括测量三种不同速度下的膝关节伸肌的峰值扭矩，评估 3 分钟间歇性强度膝关节伸肌运动的总功（Wtot），以及测量血液代谢物（氨、乳酸、葡萄糖和尿素）。在角速度为 1.57 rad·s(-1)（218.6±40.9 与 234.4±42.2 N·m；p=0.013）和 3.14 rad·s(-1)（100.3±27.8 与 111.7±26.2 N·m；p=0.008）时，测试 2 的绝对峰值扭矩低于测试 1。与体重相关的峰值扭矩在任何速度下均保持不变。测试 2 的绝对 Wtot 低于测试 1（6359±2326 与 7452±3080 J；p=0.003），与体重相关的 Wtot 也低于测试 1（89.1±29.9 与 98.6±36.4 J·kg(-1)；p=0.034）。由于 RBML，血浆尿素浓度从 4.9 增加到 5.9 mmol·l(-1)（p=0.003）。与测试 1 相比，测试 2 后样本中氨的浓度趋于更高（80.9±29.1 与 67.6±26.5 mmol·l(-1)；p=0.082）。运动后血浆乳酸和葡萄糖的反应在测试 1 和测试 2 中相似。我们得出结论，自选的 RBML 方案会损害 3 分钟间歇性强度运动中的肌肉性能，并在经验丰富的男性搏击运动员中引起血尿素浓度升高。要点：先前的研究表明，快速体重减轻对表现有负面影响。然而，有些表现特征可能不会改变，甚至可能会有所提高。在许多先前的研究中，用于诱导快速体重减轻的方法是由研究人员规定的，而不是由受试者选择的。先前的研究中，对表现有负面影响的快速体重减轻的测试持续时间也相对较长（5-6 分钟）。我们评估了自选快速体重减轻方案对经验丰富的男性搏击运动员肌肉性能和 3 分钟间歇性强度运动代谢反应的急性影响。结果表明，自选快速体重减轻方案会损害 3 分钟间歇性强度运动中的肌肉性能，并导致血尿素浓度升高。因此，最近一些项目（摔跤）规则的改变，包括比赛时间的缩短，并没有降低快速体重减轻对运动员表现能力的负面影响发生的可能性。
