Abstract：
Combat sports athletes often undergo rapid body mass loss (BML), which presents health risks. Hydration testing has been proposed as a possible solution to reduce or eliminate rapid BML. However, combat sports athletes may exhibit distinct physiological characteristics due to repeated exposure to BML. Thus, traditional and emerging hydration biomarkers should be investigated to determine their potential suitability for field use in this cohort. This study examined whether BML can explain changes in serum and urine osmolality (SosmΔ, UosmΔ), tear osmolarity (TosmΔ), hematocrit (HctΔ), and urine-specific gravity (USGΔ) after mild-moderate passive dehydration. Biomarker reliability was also assessed across two trials. Fifteen male and female combat sports athletes (age: 26.3 ± 5.3 years, body mass: 67.7 ± 9.9 kg) underwent a sauna protocol twice (5-28 days apart) aiming for 4% BML. The average BML in Trials 1 and 2 was 3.0 ± 0.7%. Regression analysis revealed that BML explained HctΔ (R2 = 0.22, p = 0.009) but not SosmΔ (R2 = 0.11, p = 0.079) or other biomarkers. Intraclass correlation coefficients (ICCs) were significant for all biomarkers except TosmΔ (ICC = 0.06, p = 0.37) and post-Tosm (ICC = 0.04, p = 0.42); post-Hct performed best (ICC = 0.82, p < 0.001). Contingency tables with post-Sosm (295 mOsm/kg) and post-USG (1.020) cutoffs revealed an 80% true negative rate (TNR) and a 62% true positive rate (TPR). Increasing the Sosm cutoff to 301 mOsm/kg decreased the TNR to 52% but increased the TPR to 83%. Although blood parameters were most sensitive to BML, they could only explain 11%-22% of biomarker variation. The typical USG cutoff misclassified 42% of athletes postdehydration, and reliability was generally poor-moderate. Alternative strategies should be pursued to manage rapid BML in combat sports.
摘要：
战斗运动运动员经常经历快速体重下降（BML），这带来了健康风险。已提出水合测试作为减少或消除快速BML的可能解决方案。然而,由于反复暴露于BML，战斗运动运动员可能表现出明显的生理特征。因此，应研究传统和新兴的水合生物标志物,以确定它们在本队列中的现场使用的潜在适用性.这项研究检查了BML是否可以解释血清和尿液渗透压的变化(SosmΔ，UosmΔ)，泪液渗透压(TosmΔ)，血细胞比容（HctΔ），轻度-中度被动脱水后的尿液比重（USGΔ）。还在两个试验中评估了生物标志物的可靠性。15名男女格斗运动运动员（年龄：26.3±5.3岁，体重：67.7±9.9kg）接受了两次桑拿方案（间隔5-28天），目标是4％BML。试验1和2中的平均BML为3.0±0.7%。回归分析显示，BML解释了HctΔ（R2=0.22，p=0.009），而不是SosmΔ（R2=0.11，p=0.079）或其他生物标志物。除TosmΔ（ICC=0.06，p=0.37）和Tosm后（ICC=0.04，p=0.42）外，所有生物标志物的组内相关系数（ICC）均显着；Hct后表现最佳（ICC=0.82，p<0.001）。Sosm后（295mOsm/kg）和USG后（1.020）截止时间的应急表显示，真实阴性率（TNR）为80％，真实阳性率（TPR）为62％。将Sosm截止值增加到301mOsm/kg将TNR降低到52%,但将TPR增加到83%。尽管血液参数对BML最敏感,它们只能解释11%-22%的生物标志物变异.典型的USG临界值错误分类了42％的运动员脱水后，可靠性一般较差-中等。应该采取替代策略来管理格斗运动中的快速BML。
