Ischemic preconditioning enhances critical power during a 3 minute all-out cycling test.

This study tested the hypothesis that ischemic preconditioning (IPC) would increase critical power (CP) during a 3 minute all-out cycling test. Twelve males completed two 3 minute all-out cycling tests, in a crossover design, separated by 7 days. These tests were preceded by IPC (4 x 5 minute intervals at 220 mmHg bilateral leg occlusion) or SHAM treatment (4 x 5 minute intervals at 20 mmHg bilateral leg occlusion). CP was calculated as the mean power output during the final 30 s of the 3 minute test with W' taken as the total work done above CP. Muscle oxygenation was measured throughout the exercise period. There was a 15.3 ± 0.3% decrease in muscle oxygenation (TSI; [Tissue saturation index]) during the IPC stimulus, relative to SHAM. CP was significantly increased (241 ± 65 W vs. 234 ± 67 W), whereas W' (18.4 ± 3.8 vs 17.9 ± 3.7 kJ) and total work done (TWD) were not different (61.1 ± 12.7 vs 60.8 ± 12.7 kJ), between the IPC and SHAM trials. IPC enhanced CP during a 3 minute all-out cycling test without impacting W' or TWD. The improved CP after IPC might contribute towards the effect of IPC on endurance performance.

Effects of local versus remote ischemic preconditioning on repeated sprint running performance.

BACKGROUND: The aim of this study was to compare the effect of local and remote ischemic preconditioning (IPC) on repeated sprint exercise. METHODS: Twelve males (age 22±2 years; stature 1.79±0.07 m; body mass 77.8±8.4 kg; mean±SD) completed four trials consisting of remote (arm) and local (leg) IPC and SHAM interventions prior to repeated sprint exercise (3x[6x15+15-m] shuttle sprints), in a double-blind, randomized, crossover designed study. These tests were immediately preceded by IPC (4x5-minute intervals at 220 mmHg bilateral occlusion) or SHAM treatment (4x5-minute intervals at 20 mmHg bilateral occlusion). Sprint performance and percentage decrement score alongside measurement of Tissue Saturation Index, blood lactate and RPE were measured throughout the intervention. RESULTS: During the IPC/SHAM intervention there was a large decrease in TSI for IPC-arm in comparison to IPC-leg (P<0.05), however IPC-legs resulted in greater soreness compared with the other three conditions (P<0.05). There was no main effects or interaction effects for sprint performance. There was a significant effect of condition (P=0.047, r=0.56) on percentage decrement score across all 18 sprints with IPC demonstrating less fatigue than SHAM. There were no other effects of IPC during the sprint trials for any other physiological measure. CONCLUSIONS: In conclusion local IPC resulted in more pain/soreness during the IPC/SHAM intervention but both remote and local IPC reduced the fatigue associated with repeated sprint exercise.