Institute of Biomedical Technologies, National Research Council, Segrate, ITALY.
Department of Medicine, University of Udine, Udine, ITALY.
Med Sci Sports Exerc. 2019 Dec;51(12):2595-2602. doi: 10.1249/MSS.0000000000002077.
Lactate thresholds are physiological parameters used to train athletes and monitor performance or training. Currently, the assessment of lactate thresholds in kayakers is performed in a laboratory setting utilizing specific ergometers; however, laboratory tests differ from on-water evaluation for several reasons. The aim of this study was to assess reliability and validity of a new on-water incremental test for the assessment of blood lactate response to exercise in flat-water kayakers. Maximal lactate steady state test (MLSS) was used as criterion measurement.
Eleven junior (16.5 ± 1.9 yr) élite flat-water kayakers performed: i) an incremental cardiopulmonary test up to voluntary exhaustion on a stationary kayak ergometer to determine peak oxygen uptake; ii) an on-water 1000-m distance trial (T1000) to record best performance time and average speed (S1000); iii) two repetitions of on-water incremental kayaking test (WIK test); iv) several repetitions of on-water constant speed tests to determine MLSS. Speed, HR, and blood lactate concentrations were determined during on-water tests.
The best performance time in T1000 was 262 ± 13 s, corresponding to an S1000 of 3.82 ± 0.19 m·s. Lactate threshold determined by modified Dmax method (LTDmod) during WIK test was 2.78 ± 1.02 mmol·L and the corresponding speed (SLT) was 3.34 ± 0.16 m·s. Test-retest reliability, calculated on SLT, was strong (ICC = 0.95 and r = 0.93). MLSS test corresponded to 3.06 ± 0.68 mmol·L and was reached at a speed (SMLSS) of 3.36 ± 0.14 m·s. Correlation coefficient between SLT and SMLSS was 0.90 (P = 0.0001). Interestingly, a significant correlation (r = 0.96, P < 0.0001) was observed between SLT and S1000.
The WIK test showed good reliability and validity for the assessment of speed corresponding to LTDmod in flat-water kayakers and it could be a useful tool to monitor athletic performance. The speed value at LTDmod nicely predicted performance on 1000 m.
乳酸阈是用于训练运动员和监测运动表现或训练的生理参数。目前，赛艇运动员的乳酸阈评估是在实验室环境中利用特定测功计进行的；然而，由于多种原因，实验室测试与水上评估不同。本研究的目的是评估一种新的水上递增测试评估静水赛艇运动员运动时血乳酸反应的可靠性和有效性。最大乳酸稳态测试（MLSS）被用作标准测量。
11 名初级（16.5±1.9 岁）精英静水赛艇运动员进行了以下测试：i）在固定测功器上进行递增心肺测试，直至自愿力竭，以确定最大摄氧量；ii）进行 1000 米水上距离试验（T1000），记录最佳成绩时间和平均速度（S1000）；iii）两次重复水上递增赛艇测试（WIK 测试）；iv）多次重复水上定速测试以确定 MLSS。在水上测试过程中确定速度、HR 和血乳酸浓度。
T1000 的最佳成绩时间为 262±13 秒，对应的 S1000 为 3.82±0.19 m·s。WIK 测试中使用改良 Dmax 法（LTDmod）确定的乳酸阈为 2.78±1.02 mmol·L，对应的速度（SLT）为 3.34±0.16 m·s。基于 SLT 计算的测试-再测试可靠性很强（ICC=0.95，r=0.93）。MLSS 测试对应于 3.06±0.68 mmol·L，在速度（SMLSS）为 3.36±0.14 m·s 时达到。SLT 和 SMLSS 之间的相关系数为 0.90（P=0.0001）。有趣的是，SLT 与 S1000 之间存在显著相关性（r=0.96，P<0.0001）。
WIK 测试对评估静水赛艇运动员 LTDmod 对应的速度具有良好的可靠性和有效性，它可能是监测运动表现的有用工具。LTDmod 时的速度值很好地预测了 1000 米的成绩。
