• Peter Sørensen Jokumsen
  • Frank ter Beek
4. semester, Sports Science, Master (Master Programme)
Purpose: Brief consecutive periods of limb ischemia and reperfusion induced by a blood pressure cuff, known as ischemic preconditioning (IPC), have been reported to increase maximal power output (MPO) and maximal oxygen consumption (VO2max) during maximal incremental cycle ergometer tests. However, the underlying mechanisms are still unclear. Therefore, the purpose of the study was to investigate the effects of IPC on MPO, VO2max, RPE, and underlying performance related parameters. Methods: A double-blinded, randomized crossover study design was utilized to investigate the effects of IPC, consisting of four five-minutes cycles of ischemia interspersed with five minutes of reperfusion, on cycle ergometer performance, underlying physiological parameters, and rating of perceived exertion (RPE). Fourteen young, healthy men reported to the laboratory three times; one familiarization session and two intervention sessions, with two and seven days of rest and washout in between, respectively. After the familiarization test, in which the maximal incremental cycle ergometer test was completed, the participants were stratified and randomized into two different conditions (IPC and sham). During the two intervention sessions, in order to counterbalance, participants initially received either the IPC (250 mmHg) or sham (20 mmHg) treatment. Subsequently, the participants performed a step-transition test and a maximal incremental cycle ergometer test. During the second intervention session, the participants received the remaining treatment to complete the crossover. The researchers responsible for the cycling tests were blinded to the intervention, and the IPC and sham responsible researcher was absent while participants cycled. During both cycling tests, MPO, VO2max, submaximal VO2, rating of perceived exertion (RPE) on a Borg 6-20 scale, heart rate (HR), blood lactate concentration (BL) as well as NIRS-derived muscle oxygenation (tissue saturation index, TSI), ▲deoxygenated hemoglobin (▲HHb) and ▲oxygenated hemoglobin (▲O2Hb) were measured. Results: MPO, VO2max, HRmax, and maximal deoxygenation (minimum TSI) did not significantly change with IPC compared to sham (all P-values > 0.13). Furthermore, IPC had no significant effect on VO2, HR, TSI, ▲HHb, and ▲O2Hb during the submaximal workloads of the incremental cycling test (all P-values > 0.18). However, IPC did significantly attenuate RPE during cycling at 245 W (P = 0.007) and 280 W (P = 0.011), but not at 105 W (P = 0.145), 140 W (P = 0.034), or 175 W (P = 0.020). The P-values at 140 W and 175 W were non-significant due to the Holm-Bonferroni correction of the significance level. Furthermore, IPC had no significant effect on VO2, HR, BL, and RPE at 50 W and at 60% of ventilatory threshold in the steptransition test (all P-values > 0.11). Conclusion: The present study demonstrated that IPC did not improve MPO and VO2max, or affect any of the measured underlying physiological parameters, for young, healthy males during a maximal incremental cycle ergometer test and a step-transition test. However, IPC significantly attenuated the RPE of the participants during cycling at 245 W and 280 W.
Publication date2019
Number of pages23
ID: 292682595