Effects of a six-week period of congested match play on plasma volume variations, hematological parameters, training workload and physical fitness in elite soccer players

ObjectivesThe aims of this study were to investigate the effects of a six-week in-season period of soccer training and games (congested period) on plasma volume variations (PV), hematological parameters, and physical fitness in elite players. In addition, we analyzed relationships between training load, hematological parameters and players’ physical fitness.MethodsEighteen elite players were evaluated before (T1) and after (T2) a six-week in-season period interspersed with 10 soccer matches. At T1 and T2, players performed the Yo-Yo intermittent recovery test level 1 (YYIR1), the repeated shuttle sprint ability test (RSSA), the countermovement jump test (CMJ), and the squat jump test (SJ). In addition, PV and hematological parameters (erythrocytes [M/mm3], hematocrit [%], hemoglobin [g/dl], mean corpuscular volume [fl], mean corpuscular hemoglobin content [pg], and mean hemoglobin concentration [%]) were assessed. Daily ratings of perceived exertion (RPE) were monitored in order to quantify the internal training load.ResultsFrom T1 to T2, significant performance declines were found for the YYIR1 (pConclusionsAn intensive period of “congested match play” over 6 weeks significantly compromised players’ physical fitness. These changes were not related to hematological parameters, even though significant alterations were detected for selected measures.

研究目标
本研究旨在探讨为期6周的赛季内足球训练与赛事密集周期（赛程密集期）对精英足球运动员血浆容量变化（plasma volume variations, PV）、血液学参数以及体能水平的影响。此外，本研究还分析了训练负荷、血液学参数与运动员体能之间的关联关系。

研究方法
本研究纳入18名精英足球运动员，在为期6周、穿插10场足球赛事的赛季内赛程密集周期的前后两个时间点（分别记为T1、T2）对其进行评估。在T1与T2两个时间点，运动员完成了Yo-Yo间歇恢复测试1级（Yo-Yo intermittent recovery test level 1, YYIR1）、重复穿梭冲刺能力测试（repeated shuttle sprint ability test, RSSA）、反向跳跃测试（countermovement jump test, CMJ）以及蹲跳测试（squat jump test, SJ）。此外，本研究还检测了血浆容量（PV）及各项血液学参数，包括红细胞[M/mm³]、血细胞比容[%]、血红蛋白[g/dl]、平均红细胞体积[fl]、平均红细胞血红蛋白含量[pg]以及平均血红蛋白浓度[%]。同时，通过每日记录自觉劳累分级（ratings of perceived exertion, RPE）来量化内部训练负荷。

研究结果
从T1至T2，Yo-Yo间歇恢复测试1级（YYIR1，p<0.05）、重复穿梭冲刺能力测试（RSSA，p<0.01）、反向跳跃高度（CMJ，p<0.001）以及蹲跳高度（SJ，p<0.01）均出现显著性能下降。血液学参数未出现显著变化，仅血细胞比容出现轻微降低（p<0.05）。血浆容量（PV）显著下降4.2%（p<0.01）。赛程密集期内的内部训练负荷显著升高（p<0.001）。训练负荷、血液学参数与运动员体能之间的关联未达到统计学显著性水平。

研究结论
为期6周的高强度"密集赛事周期"会显著损害运动员的体能水平。尽管部分指标出现了显著变化，但上述体能变化与血液学参数并无关联。