Repeated-sprint performance and vastus lateralis oxygenation: effect of limited O₂ availability.
This study examined the influence of muscle deoxygenation and reoxygenation on repeated-sprint performance via manipulation of O2 delivery. Fourteen team-sport players performed 10 10-s sprints (30-s recovery) under normoxic (NM: FI O2 0.21) and acute hypoxic (HY: FI O2 0.13) conditions in a randomized, single-blind fashion and crossover design. Mechanical work was calculated and arterial O2 saturation (Sp O2 ) was estimated via pulse oximetry for every sprint. Muscle deoxyhemoglobin concentration ([HHb]) was monitored continuously by near-infrared spectroscopy. Differences between NM and HY data were analyzed for practical significance using magnitude-based inferences. HY reduced Sp O2 (-10.7 ± 1.9%, with chances to observe a higher/similar/lower value in HY of 0/0/100%) and mechanical work (-8.2 ± 2.1%; 0/0/100%). Muscle deoxygenation increased during sprints in both environments, but was almost certainly higher in HY (12.5 ± 3.1%, 100/0/0%). Between-sprint muscle reoxygenation was likely more attenuated in HY (-11.1 ± 11.9%; 2/7/91%). The impairment in mechanical work in HY was very largely correlated with HY-induced attenuation in muscle reoxygenation (r = 0.78, 90% confidence limits: 0.49; 0.91). Repeated-sprint performance is related, in part, to muscle reoxygenation capacity during recovery periods. These results extend previous findings that muscle O2 availability is important for prolonged repeated-sprint performance, in particular when the exercise is taken in hypoxia.
Institut national du sport du Québec, Montréal, Canada. fbillaut@insquebec.org
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Billaut
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Buchheit
D000328:Adult; D054874:Athletic Performance / Q000502:physiology*; D018592:Cross-Over Studies; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D000860:Hypoxia / Q000097:blood* / Q000378:metabolism; D008297:Male; D010092:Oximetry; D010100:Oxygen / Q000097:blood* / Q000378:metabolism; D005082:Physical Exertion / Q000502:physiology; D052097:Quadriceps Muscle / Q000378:metabolism*; D012146:Rest / Q000502:physiology; D012420:Running / Q000502:physiology*; D012885:Skinfold Thickness; D055815:Young Adult
D006454:Hemoglobins; C100003:deoxyhemoglobin; D010100:Oxygen