title: Criteria and other methodological considerations in the evaluation of time at V.O2max.
abstract: OBJECTIVE
  Many previous studies have examined the time limit at which an individual can maintain VO(2max) (T(lim) VO(2max)) during high-intensity continuous and intermittent runs to exhaustion. The main purpose of the present study was to examine the effects of employing different criteria used in previous investigations during T(lim) VO(2max) evaluation.
  
  
  METHODS
  Seven moderately trained competitive runners completed 2 running tests to exhaustion, during which metabolic data was obtained from breath-by-breath gas analysis. The 1(st) test was an incremental test to evaluate VO(2max) and the minimal running velocity at which VO(2max) was elicited (v VO(2max)). The 2(nd) test was a continuous single velocity test at v VO(2max) from which the time to attain VO(2max) (TA VO(2max)) and T(lim) VO(2max) were subsequently evaluated. Time at VO(2max) was evaluated employing 6 specific criteria. Intra-individual differences in T(lim) VO(2max) values due to applying the different criteria were analysed using a one-way ANOVA, with significant differences between pairs identified using Tukey's HSD posthoc test. Significance was set at p<0.05.
  
  
  RESULTS
  A one-way ANOVA demonstrated that significant differences (F=4.03, p=0.005) existed between T(lim) VO(2max) values generated by employing the six different criteria.
  
  
  CONCLUSIONS
  The present study provides support that employing different criteria in the evaluation of T(lim) VO(2max), such as those used in previous investigations, leads to significantly different T(lim) VO(2max) values. However, the practical implications of these measurement differences require further investigation.
authors.affiliation: Departments of Sport, Health and Exercise Science, University of Hull, Hull, England.
authors.forename: A W
authors.initials: AW
authors.lastname: Midgley
authors.forename: L R
authors.initials: LR
authors.lastname: Mc Naughton
authors.forename: M
authors.initials: M
authors.lastname: Wilkinson
mesh_terms: D000328:Adult; D002138:Calibration; D002245:Carbon Dioxide / Q000032:analysis; D005080:Exercise Test / Q000379:methods / Q000706:statistics & numerical data; D017079:Exercise Tolerance / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D010100:Oxygen / Q000032:analysis; D010101:Oxygen Consumption / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology; D010809:Physical Fitness / Q000502:physiology*; D012420:Running / Q000502:physiology*; D013997:Time Factors
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen