Lu, K.-H., Chang, C.-Y., & Chan, K.-H. (2014). Ischemic preconditioning does not improve isokinetic muscle strength and endurance in humans. Medicine & Science in Sports & Exercise, 46(5), Supplement abstract number 961.

“Repeated brief episodes of occlusion-induced ischemia followed by reperfusion, commonly known as ischemic preconditioning (IPC), is a noninvasive technique which has been reported to enhance athletic performance such as cycling, swimming, and running. The mechanism of IPC was considered with increasing blood flow and muscle oxygenation. We hypothesized that the benefit of IPC in sports might be caused by improving muscle function.“

This study examined the effects of ischemic preconditioning on human muscle strength and endurance as well as blood flow and oxygenation in healthy males (N = 14). Ss completed two isokinetic exercise tests preceded by ischemic preconditioning or low-pressure control. The ischemic preconditioning protocol was three cycles of five minutes of ischemia followed by five minutes of reperfusion on both legs alternately. Occlusive cuffs were positioned around the thighs and inflated to 50 mm Hg above each S’s systolic blood pressure for ischemic preconditioning or 10 mm Hg for the control condition. The isokinetic exercise test consisted of knee extension at low (30°/s), moderate (150°/s), and high (270°/s) angular velocity, followed by 30 repetitions at 180°/s. Levels of oxygenated, deoxygenated, and total hemoglobin represented blood flow as well as saturation and were determined by the quantitative near-infrared spectroscopy before and after both conditions and during continuous 30-repetition knee extensions every 10 seconds.

Ischemic preconditioning did not improve muscle strength. There was no significant difference in muscle endurance between both conditions. All the patterns of near-infrared spectroscopy parameters were similar between ischemic preconditioning and the control condition at baseline, after treatment, and during repeated knee-extensions. Results might be limited because only microvascular was detected by near-infrared spectroscopy.

Implication. No beneficial effects of ischemic preconditioning on isokinetic muscle strength and endurance were found in healthy males. Ischemic preconditioning did not influence muscle blood flow or oxygenation.

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