title: Magnitude and time course of changes in maximal oxygen uptake in response to distinct regimens of chronic interval training in sedentary women.
abstract: OBJECTIVE
  This study aimed to compare changes in maximal oxygen uptake (VO2max) in response to two regimens of chronic interval training.
  
  
  METHODS
  Twenty healthy sedentary women (mean ± SD age and VO2max = 23.0 ± 5.7 years and 30.1 ± 4.4 mL kg(-1) min(-1), respectively) were randomized to complete 12 weeks of one of two interval training regimes, while an additional seven women served as controls. Training was performed 3 days week(-1) on a cycle ergometer and consisted of 6-10 bouts of 1 min duration at lower (60-80 % W max = LO, n = 10) or more intense (80-90 % W max = HI, n = 10) workloads separated by a brief recovery. Every 3 weeks, measures of VO2max and W max were repeated to assign new training intensities. Changes in blood pressure and body composition were also examined.
  
  
  RESULTS
  Data revealed significant (p < 0.001) improvements in VO2max in LO (22.3 ± 6.9 %) and HI (21.9 ± 11.6 %) that were similar (p > 0.05) between groups. Approximately 60 % of the increase in VO2max in HI was observed in the initial 3 weeks, compared to only 20 % in LO. No change (p > 0.05) in body weight or body composition was revealed in response to training. Results demonstrate that a relatively prolonged regimen of moderate or more intense interval training induces similar improvements in cardiorespiratory fitness, although HI induced greater increases in VO2max early on in training than LO. Completion of more intense interval training may be an effective means to expedite increases in VO2max soon after initiation of exercise training.
authors.affiliation: Department of Kinesiology, California State University, 333 S. Twin Oaks Valley Road, UNIV 320, San Marcos, CA 92096-0001, USA. astorino@csusm.edu
authors.forename: Todd A
authors.initials: TA
authors.lastname: Astorino
authors.forename: Matthew M
authors.initials: MM
authors.lastname: Schubert
authors.forename: Elyse
authors.initials: E
authors.lastname: Palumbo
authors.forename: Douglas
authors.initials: D
authors.lastname: Stirling
authors.forename: David W
authors.initials: DW
authors.lastname: McMillan
authors.forename: Christina
authors.initials: C
authors.lastname: Cooper
authors.forename: Jackie
authors.initials: J
authors.lastname: Godinez
authors.forename: Donovan
authors.initials: D
authors.lastname: Martinez
authors.forename: Rachael
authors.initials: R
authors.lastname: Gallant
mesh_terms: D000293:Adolescent; D000328:Adult; D001794:Blood Pressure / Q000502:physiology; D001823:Body Composition / Q000502:physiology; D001835:Body Weight / Q000502:physiology; D004493:Education / Q000379:methods*; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000379:methods; D005260:Female; D006801:Humans; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology*; D055815:Young Adult
chemical_list: D010100:Oxygen