Nike Sport Research Lab, Nike, Inc., Beaverton, OR.
Med Sci Sports Exerc. 2019 Feb;51(2):308-314. doi: 10.1249/MSS.0000000000001774.
We tested the hypothesis that critical velocity (CV) during intermittent running with changes of direction is reliably and accurately identified from a simple shuttle field test. We also tested the hypothesis that CV during intermittent running with changes of direction running is not equivalent to continuous linear running.
Young adults performed a custom shuttle test of intermittent sprint running to reveal CV. Sprints were 18.3 m per direction, with rest between sprints of 15 s for 3 min, 10 s for 2 min, and no rest for 2 min (7 min total). To test reliability, the CV shuttle test (CVST) was performed twice. To test validity, blood lactate was assessed during two separate trials inclusive of 5% above or below CVST end velocity. To explore task specificity, CV during CVST was compared to CV obtained from three linear running time trials.
Total distance and CSVT end test velocity were similar between visits (864 ± 21 m and 3.23 ± 0.13 m·s vs 900 ± 30 m and 3.21 ± 0.15 m·s, respectively). At 5% above CVST end velocity, all subjects failed to complete 20 min and had unstable blood lactate values. A steady state blood lactate profile was observed during trials 5% below end velocity and all subjects completed the trial. The CV from the CVST was lower than the CV from linear running (△ -17% ± 6%), highlighting the importance of test specificity for threshold determination.
The CVST provides a reliable and accurate determination of CV and can be used by coaches, athletes, and trainers to better understand the physiological impact specific to practice or competitions involving intermittent change of direction running.
我们通过一项简单的折返跑场测试来验证这样一个假设，即在有方向变化的间歇性跑步中，临界速度（CV）可以被可靠且准确地识别。我们还测试了这样一个假设，即在有方向变化的间歇性跑步中，CV 与连续直线跑步是不等同的。
年轻人进行了一项定制的间歇冲刺跑折返场测试，以揭示 CV。每个方向的冲刺距离为 18.3 米，冲刺之间的休息时间为 15 秒（3 分钟）、10 秒（2 分钟）和无休息（2 分钟）（总时长 7 分钟）。为了测试可靠性，CV 折返测试（CVST）进行了两次。为了测试有效性，在两次单独的试验中评估了血乳酸，其中包括在 CVST 结束速度以上或以下 5%的速度进行。为了探索任务特异性，将 CVST 中的 CV 与三个直线跑步时间试验中的 CV 进行了比较。
两次访问的总距离和 CVST 结束测试速度相似（分别为 864 ± 21 m 和 3.23 ± 0.13 m·s 与 900 ± 30 m 和 3.21 ± 0.15 m·s）。在 CVST 结束速度以上 5%的情况下，所有受试者都未能完成 20 分钟，且血乳酸值不稳定。在低于 CVST 结束速度 5%的试验中观察到稳定的血乳酸谱，所有受试者都完成了试验。CVST 中的 CV 低于直线跑步中的 CV（差值为-17%±6%），这突出了测试特异性对阈值确定的重要性。
CVST 可提供可靠且准确的 CV 测定，可被教练、运动员和培训师用于更好地理解涉及方向变化的间歇性跑步的实践或比赛中特定的生理影响。
