Ischemic Preconditioning On Swimming Performance: An Exploration Into Practical Application

Ischemic preconditioning (IPC), an athletic aid under review for its applicability to aerobic sports, has garnered conflicting results in the last decade of study. The ischemia and subsequent reperfusion have been theorized to induce ergogenic effects beneficial for exercise capabilities. The precise physiological mechanisms associated with performance improvements are still unknown. Observations of increased blood flow to skeletal muscle, oxygen extraction, and glycolytic contributions post- IPC give rise to IPCs theorized effects. PURPOSE: To determine the impact of IPC on two swimming distances similar to a competitive performance. METHODS: This research investigated the effects of ischemic preconditioning over distances of 250 and 500 yards while imposing commonly suggested methodologies especially for the control of placebo/nocebo, means of occlusion, and duration of test. A pool of college-aged swimmers, including recreational and competitive, was given IPC treatment with personalized limb occlusion pressure accompanied by a sham protocol. Specifically, an automated tourniquet was applied for 1 min. (sham) or 5 min. (intervention) with three cycles of one hundred percent occlusion. Researchers requested maximal effort during the trials and collected pain and exertion scores at multiple points. Comparison of times between IPC and sham groups was done using paired Welch t-tests. RESULTS: The 250-yard trials saw an improvement, with a difference between IPC time (213.35 + 61.60) and sham time (215.29 + 62.98) of 1.94 seconds (p-value = 0.02). No statistical distance (p-value = 0.53) was found between the 500-yard trials, IPC (422.47 + 101.69) and sham (423.47 + 102.38). Regardless of distance, there was no significant variation in VAS or RPE scores between treatments. Also, personalized limb occlusion pressure was determined necessary to ensure proper occlusion for all participants. CONCLUSION: IPC may have a short period of benefit, and the focus of further study, if any, should be on mechanisms, practical application, and continued methodological standardization. Research was supported by SD BRIN from NIH IDeA grant P20GM103443, but content here solely reflects views of the authors. Research was conducted after approval from the IRB of Augustana University (Number SP20.03).