Department of Sport Science, Aspire Academy, Doha, Qatar.
Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool, UK.
Eur J Sport Sci. 2021 Feb;21(2):166-175. doi: 10.1080/17461391.2020.1749312. Epub 2020 Apr 16.
Both ischaemic preconditioning (IPC) and muscle heat maintenance can be effective in enhancing repeated-sprint performance (RSA) when applied individually, acting mechanisms of these interventions, however, likely differ. It is unclear if, when combined, these interventions could further improve RSA. Eleven trained cyclists undertook experimental test sessions, whereby IPC (4 × 5-min at 220 mmHg) and SHAM (4 × 5-min at 20 mmHg) were each performed on two separate visits, each combined with either passive muscle heating or thermoneutral insulation prior to an "all-out" repeated-sprint task (10 × 6-s sprints with 24-s recovery). Primary outcome measures were peak and average power output (W), whist secondary measures were muscular activation and muscular oxygenation, measured via Electromyography (EMG) and Near-infrared spectroscopy (NIRS), respectively. IPC did not enhance peak [6 (-14-26)W; = 0.62] or average [12 (-7-31)W; = 0.28] power output SHAM. Additionally, no performance benefits were observed when increasing muscle temperature in combination with IPC [5 (-14-19) watts; = 0.67], or in isolation to IPC [9 (-9-28)W; = 0.4] SHAM. No changes in EMG or microvascular changes were present (> 0.05, respectively) between conditions. Overall, neither IPC, muscle heating, or a combination of both enhances RSA cycling performance in trained individuals.
缺血预处理 (IPC) 和肌肉热维持在单独应用时都可以有效地增强重复冲刺表现 (RSA),但这些干预措施的作用机制可能不同。目前尚不清楚这些干预措施是否结合使用可以进一步提高 RSA。11 名训练有素的自行车运动员参加了实验测试,其中 IPC(4×5 分钟,220mmHg)和 SHAM(4×5 分钟,20mmHg)分别在两次单独的访问中进行,每次访问都与被动肌肉加热或热中性隔热相结合,然后进行“全力以赴”的重复冲刺任务(10×6 秒冲刺,24 秒恢复)。主要结果测量指标是峰值和平均功率输出(W),次要结果测量指标是肌肉激活和肌肉氧合,分别通过肌电图(EMG)和近红外光谱(NIRS)测量。IPC 并没有增强峰值 [6(-14-26)W;=0.62] 或平均 [12(-7-31)W;=0.28] 功率输出 SHAM。此外,当与 IPC 一起增加肌肉温度时,或与 IPC 分开增加肌肉温度时,都没有观察到性能的提高 [5(-14-19)瓦;=0.67] 或 SHAM。在条件之间没有出现 EMG 或微血管变化(>0.05,分别)。总的来说,IPC、肌肉加热或两者的组合都不能增强训练有素的个体的 RSA 自行车表现。