title: Psychophysiological Responses to Repeated-Sprint Training in Normobaric Hypoxia and Normoxia.
abstract: OBJECTIVE
  To compare psychophysiological responses to 6 repeated-sprint sessions in normobaric hypoxia (RSH) and normoxia (RSN) in team-sport athletes during a 2-wk "live high-train low" training camp.
  
  
  METHODS
  While residing under normobaric hypoxia (≥14 h/d, FiO214.5-14.2%), 23 lowland elite field hockey players performed, in addition to their usual training, 6 sessions (4 × 5 × 5-s maximal sprints, 25-s passive recovery, 5 min rest) under either RSH (FiO2~14.5%) or RSN (FiO221%). Sprint 1 and 5 times, physiological strain (heart rate [HR], arterial oxyhemoglobin saturation [SpO2]), and perceptual responses (overall peripheral discomfort, difficulty breathing, and lower-limb discomfort) were monitored.
  
  
  RESULTS
  During the 1st session, HR increased across sets (P < .001) independently of the conditions, while SpO2was globally lower (P < .001) for RSH (averaged value: 91.9% ± 1.2%) vs RSN (96.9% ± 0.6%). Thereafter, SpO2and HR remained similar across sessions for each condition. While 1st-sprint time remained similar, last-sprint time and fatigue index significantly decreased across sets (P < .01) and sessions (P < .05) but not between conditions. Ratings of overall perceived discomfort, difficulty breathing, and lower-limb discomfort were higher (P < .05) in RSH vs RSN at the 1st session. During subsequent sessions, values for overall perceived discomfort (time [P < .001] and condition [P < .05] effects), difficulty breathing (time effect; P < .001), and lower-limb discomfort (condition [P < .001] and interaction [P < .05] effects) decreased to a larger extent in RSH vs RSN.
  
  
  CONCLUSIONS
  Despite higher hypoxia-induced physiological and perceptual strain during the 1st session, perceptual responses improved thereafter in RSH so as not to differ from RSN. This indicates an effective acclimation and tolerance to this innovative training.
authors.forename: Franck
authors.initials: F
authors.lastname: Brocherie
authors.forename: Grégoire P
authors.initials: GP
authors.lastname: Millet
authors.forename: Olivier
authors.initials: O
authors.lastname: Girard
mesh_terms: D000064:Acclimatization / Q000502:physiology; D000328:Adult; D000531:Altitude; D054874:Athletic Performance / Q000502:physiology* / Q000523:psychology*; D005221:Fatigue / Q000503:physiopathology; D006339:Heart Rate / Q000502:physiology; D006688:Hockey / Q000502:physiology* / Q000523:psychology*; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology; D035002:Lower Extremity / Q000502:physiology; D008297:Male; D010108:Oxyhemoglobins / Q000378:metabolism; D010465:Perception; D064797:Physical Conditioning, Human / Q000379:methods*; D005082:Physical Exertion / Q000502:physiology; D012119:Respiration; D055815:Young Adult
chemical_list: D010108:Oxyhemoglobins
keywords: acclimation; altitude; high-intensity exercise; perceived peripheral discomfort; ratings of perceived exertion; team sports