Ischemic Preconditioning Maintains Performance on Two 5-km Time Trials in Hypoxia
da Mota, Gustavo R.1,2; Willis, Sarah J.2; dos Santos, Nelson Sobral2; Borrani, Fabio2; Billaut, François3; Millet, Grégoire P.2
Medicine & Science in Sports & Exercise: May 31, 2019 - Volume Publish Ahead of Print - Issue - p
doi: 10.1249/MSS.0000000000002049
Original Investigation: PDF Only
BUY
PAP
Abstract
Author Information
Article Metrics
Purpose The ergogenic effect of ischemic preconditioning (IPC) on endurance exercise performed in hypoxia remains debated and has never been investigated with successive exercise bouts. Therefore, we evaluated if IPC would provide immediate or delayed effects during two 5 km cycling time-trials (TTs) separated by ~1 h in hypoxia.
Methods In a counterbalanced randomized cross-over design, thirteen healthy males (27.5 ± 3.6 years) performed two maximal cycling 5 km TTs separated by ~1 h of recovery (TT1 25 min and TT2 2 h post IPC/SHAM), preceded by IPC (3 × 5 min occlusion 220 mmHg/reperfusion 0 mmHg, bilaterally on thighs) or SHAM (20 mmHg) at normobaric hypoxia (inspired fraction of oxygen [FIO2] of 16%). Performance and physiological (i.e., oxyhemoglobin saturation, heart rate, blood lactate, and Vastus Lateralis oxygenation) parameters were recorded.
Results Time to complete (P = 0.011) 5 km TT and mean power output (P = 0.005) from TT1 to TT2 were worse in SHAM, but not in IPC (P = 0.381/P = 0.360, respectively). There were no differences in time, power output or in physiological variables during the two TTs between IPC and SHAM. All muscle oxygenation indices differed (P < 0.001) during the IPC/SHAM with a greater deoxygenation in IPC. During the TTs, there was a greater concentration of total hemoglobin ([tHb]) in IPC than SHAM (P = 0.047) and greater [tHb] in TT1 than TT2. Further, the concentration of oxyhemoglobin ([O2Hb]) was lower during TT2 than TT1 (P = 0.005).
Conclusion In moderate hypoxia, IPC allowed maintaining a higher blood volume during a subsequent maximal exercise, mitigating the performance decrement between two consecutive cycling time-trials.
© 2019 American College of Sports Medicine
da Mota, Gustavo R.1,2; Willis, Sarah J.2; dos Santos, Nelson Sobral2; Borrani, Fabio2; Billaut, François3; Millet, Grégoire P.2
Medicine & Science in Sports & Exercise: May 31, 2019 - Volume Publish Ahead of Print - Issue - p
doi: 10.1249/MSS.0000000000002049
Original Investigation: PDF Only
BUY
PAP
Abstract
Author Information
Article Metrics
Purpose The ergogenic effect of ischemic preconditioning (IPC) on endurance exercise performed in hypoxia remains debated and has never been investigated with successive exercise bouts. Therefore, we evaluated if IPC would provide immediate or delayed effects during two 5 km cycling time-trials (TTs) separated by ~1 h in hypoxia.
Methods In a counterbalanced randomized cross-over design, thirteen healthy males (27.5 ± 3.6 years) performed two maximal cycling 5 km TTs separated by ~1 h of recovery (TT1 25 min and TT2 2 h post IPC/SHAM), preceded by IPC (3 × 5 min occlusion 220 mmHg/reperfusion 0 mmHg, bilaterally on thighs) or SHAM (20 mmHg) at normobaric hypoxia (inspired fraction of oxygen [FIO2] of 16%). Performance and physiological (i.e., oxyhemoglobin saturation, heart rate, blood lactate, and Vastus Lateralis oxygenation) parameters were recorded.
Results Time to complete (P = 0.011) 5 km TT and mean power output (P = 0.005) from TT1 to TT2 were worse in SHAM, but not in IPC (P = 0.381/P = 0.360, respectively). There were no differences in time, power output or in physiological variables during the two TTs between IPC and SHAM. All muscle oxygenation indices differed (P < 0.001) during the IPC/SHAM with a greater deoxygenation in IPC. During the TTs, there was a greater concentration of total hemoglobin ([tHb]) in IPC than SHAM (P = 0.047) and greater [tHb] in TT1 than TT2. Further, the concentration of oxyhemoglobin ([O2Hb]) was lower during TT2 than TT1 (P = 0.005).
Conclusion In moderate hypoxia, IPC allowed maintaining a higher blood volume during a subsequent maximal exercise, mitigating the performance decrement between two consecutive cycling time-trials.
© 2019 American College of Sports Medicine
Δεν υπάρχουν σχόλια:
Δημοσίευση σχολίου