title: Vitamin C consumption does not impair training-induced improvements in exercise performance.
abstract: OBJECTIVE
  To test the hypothesis that antioxidants can attenuate high-intensity interval training-induced improvements in exercise performance.
  
  
  METHODS
  Two groups of recreationally active males performed a high-intensity interval running protocol, four times per week for 4 wk. Group 1 (n = 8) consumed 1 g of vitamin C daily throughout the training period, whereas Group 2 (n = 7) consumed a visually identical placebo. Pre- and posttraining, subjects were assessed for VO2max, 10 km time trial, running economy at 12 km/h and distance run on the YoYo intermittent recovery tests level 1 and 2 (YoYoIRT1/2). Subjects also performed a 60 min run before and after training at a running velocity of 65% of pretraining VO2max so as to assess training-induced changes in substrate oxidation rates.
  
  
  RESULTS
  Training improved (P < .0005) VO2max, 10 km time trial, running economy, YoYoIRT1 and YoYoIRT2 in both groups, although there was no difference (P = .31, 0.29, 0.24, 0.76 and 0.59) between groups in the magnitude of training-induced improvements in any of the aforementioned parameters. Similarly, training also decreased (P < .0005) mean carbohydrate and increased mean fat oxidation rates during submaximal exercise in both groups, although no differences (P = .98 and 0.94) existed between training conditions.
  
  
  CONCLUSIONS
  Daily oral consumption of 1 g of vitamin C during a 4 wk high-intensity interval training period does not impair training-induced improvements in the exercise performance of recreationally active males.
authors.affiliation: Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom.
authors.forename: Llion A
authors.initials: LA
authors.lastname: Roberts
authors.forename: Kris
authors.initials: K
authors.lastname: Beattie
authors.forename: Graeme L
authors.initials: GL
authors.lastname: Close
authors.forename: James P
authors.initials: JP
authors.lastname: Morton
mesh_terms: D000222:Adaptation, Physiological; D000284:Administration, Oral; D000328:Adult; D000975:Antioxidants / Q000008:administration & dosage*; D001205:Ascorbic Acid / Q000008:administration & dosage*; D004311:Double-Blind Method; D015444:Exercise; D005080:Exercise Test; D006801:Humans; D008297:Male; D016555:Matched-Pair Analysis; D009119:Muscle Contraction / Q000187:drug effects*; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000502:physiology; D010101:Oxygen Consumption / Q000187:drug effects; D012420:Running; D013647:Task Performance and Analysis; D013997:Time Factors; D055815:Young Adult
chemical_list: D000975:Antioxidants; D001205:Ascorbic Acid