Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Canada.
Eur J Sport Sci. 2020 Jun;20(5):633-640. doi: 10.1080/17461391.2019.1651401. Epub 2019 Aug 20.
To use repeated control trials to measure within-subject variability and assess the existence of responders to ischemic preconditioning (IPC). Secondly, to determine whether repeated IPC can evoke a dosed ergogenic response.
Twelve aerobically fit individuals each completed three control and three IPC 5-km cycling time trials. IPC trials included: (i) IPC 15-min preceding the trial (traditional IPC), (ii) IPC 24-h and 15-min preceding (IPC × 2), (iii) IPC 48-h, 24-h, and 15-min preceding (IPC × 3). IPC consisted of 3 × 5-min cycles of occlusion and reperfusion at the upper thighs. To assess the existence of a true response to IPC, individual performance following traditional IPC was compared to each individual's own 5-km TT coefficient of variation. In individuals who responded to IPC, all three IPC conditions were compared to the mean of the three control trials (CON) to determine whether repeated IPC can evoke a dosed ergogenic response.
9 of 12 (75%) participants improved 5-km time (-1.8 ± 1.7%) following traditional IPC, however, only 7 of 12 (58%) improved greater than their own variability between repeated controls (true responders). In true responders only, we observed a significant mean improvement in 5-km TT completion following traditional IPC (478 ± 50 s), IPC × 2 (481 ± 51 s), and IPC × 3 (480.5 ± 49 s) compared to mean CON (488 ± 51s; < 0.006), with no differences between various IPC trials (> 0.05).
A majority of participants responded to IPC, providing support for a meaningful IPC-mediated performance benefit. However, repeated bouts of IPC on consecutive days do not enhance the ergogenic effect of a single bout of IPC.
使用重复对照试验来测量个体内变异性，并评估对缺血预处理（IPC）有反应的个体的存在。其次，确定重复的 IPC 是否可以引起剂量性的增强作用。
12 名有氧适能良好的个体均完成了 3 次对照和 3 次 IPC 5 公里自行车计时赛。IPC 试验包括：（i）试验前 15 分钟进行 IPC（传统 IPC），（ii）试验前 24 小时和 15 分钟进行 IPC（IPC×2），（iii）试验前 48 小时、24 小时和 15 分钟进行 IPC（IPC×3）。IPC 由 3×5 分钟的大腿闭塞和再灌注循环组成。为了评估对 IPC 真正反应的存在，将传统 IPC 后个体的表现与每个个体的 5 公里 TT 变异系数进行比较。在对 IPC 有反应的个体中，将所有三种 IPC 条件与三次对照试验的平均值（CON）进行比较，以确定重复的 IPC 是否可以引起剂量性的增强作用。
12 名参与者中有 9 名（75%）在传统 IPC 后 5 公里时间缩短（-1.8±1.7%），然而，只有 12 名参与者中的 7 名（58%）的改善大于其在重复对照之间的个体内变异性（真正的反应者）。仅在真正的反应者中，我们观察到传统 IPC 后 5 公里 TT 完成的平均显著改善（478±50 秒）、IPC×2（481±51 秒）和 IPC×3（480.5±49 秒）与平均 CON（488±51 秒）相比（<0.006），不同的 IPC 试验之间没有差异（>0.05）。
大多数参与者对 IPC 有反应，这为 IPC 介导的有意义的运动表现改善提供了支持。然而，连续几天重复进行 IPC 不会增强单次 IPC 的增强作用。
