title: Metabolic response during intermittent graded sprint running in moderate hypobaric hypoxia in competitive middle-distance runners.
abstract: The purpose of this study was to determine whether the metabolic response and running performance during intermittent graded sprint running were affected by moderate hypobaric hypoxia (H; 2,500 m above sea level) in competitive middle-distance runners. Nine male runners performed intermittent graded sprint running until exhaustion, to evaluate the metabolic response and running performance in H and normobaric normoxia (N). The test constructed of incremental (25 m min(-1)) 20 s running bouts (4 degrees inclination) interspaced with 100 s recovery periods. Maximal running speed was not different between conditions [453 (7) m min(-1) vs. 458 (4) m min(-1) in N vs. H]. V(O2) at each speed was lower in H than N (ANOVA; P < 0.05). Although, oxygen deficit (D(O2)) at each speed was not different between N and H (ANOVA; P = 0.1), total accumulated D(O2) in all bouts was significantly higher in H than N [165 (10) ml kg(-1) in N and 173 (10) ml kg(-1) in H]. The ratio of D(O2).V(O2)(-1) was similar in all bouts, but higher in H than N. These results suggest that intermittent graded sprint running performance is not affected by moderate hypobaria despite a reduction in the energy supplied by aerobic metabolism due to a compensatory increase in the energy supplied by the anaerobic metabolism in competitive middle-distance runners.
authors.affiliation: Institute of Health and Sports Science, University of Tsukuba, Tsukuba City, 305-8574 Ibaraki, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ogawa
authors.forename: Keiji
authors.initials: K
authors.lastname: Hayashi
authors.forename: Masashi
authors.initials: M
authors.lastname: Ichinose
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Wada
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nishiyasu
mesh_terms: D000328:Adult; D015308:Anaerobic Threshold / Q000502:physiology; D004734:Energy Metabolism / Q000502:physiology*; D005080:Exercise Test; D006801:Humans; D000860:Hypoxia / Q000378:metabolism*; D008297:Male; D010101:Oxygen Consumption; D010807:Physical Endurance / Q000502:physiology; D012420:Running / Q000502:physiology*