title: Reliability of physiological attributes and their association with stochastic cycling performance.
abstract: OBJECTIVE
  To assess the reliability of a 5-min-stage graded exercise test (GXT) and determine the association between physiological attributes and performance over stochastic cycling trials of varying distance.
  
  
  METHODS
  Twenty-eight well-trained male cyclists performed 2 GXTs and either a 30-km (n = 17) or a 100-km stochastic cycling time trial (n = 9). Stochastic cycling trials included periods of high-intensity efforts for durations of 250 m, 1 km, or 4 km depending on the test being performing.
  
  
  RESULTS
  Maximal physiological attributes were found to be extremely reliable (maximal oxygen uptake [VO2max]: coefficient of variation [CV] 3.0%, intraclass correlation coefficient [ICC] .911; peak power output [PPO]: CV 3.0%, ICC .913), but a greater variability was found in ventilatory thresholds and economy. All physiological variables measured during the GXT, except economy at 200 W, were correlated with 30-km cycling performance. Power output during the 250-m and 1-km efforts of the 30-km trial were correlated with VO2max, PPO, and the power output at the second ventilatory threshold (r = .58-.82). PPO was the only physiological attributed measured during the GXT to be correlated with performance during the 100-km cycling trial (r = .64).
  
  
  CONCLUSIONS
  Many physiological variables from a reliable GXT were associated with performance over shorter (30-km) but not longer (100-km) stochastic cycling trials.
authors.affiliation: School of Exercise and Health Sciences, Edith Cowan University, Joondalup, WA, Australia.
authors.forename: Gregory T
authors.initials: GT
authors.lastname: Levin
authors.forename: Paul B
authors.initials: PB
authors.lastname: Laursen
authors.forename: Chris R
authors.initials: CR
authors.lastname: Abbiss
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001642:Bicycling; D005080:Exercise Test; D006801:Humans; D008297:Male; D009119:Muscle Contraction; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000378:metabolism / Q000502:physiology*; D010101:Oxygen Consumption; D010807:Physical Endurance; D012123:Pulmonary Ventilation; D015203:Reproducibility of Results; D013269:Stochastic Processes; D013647:Task Performance and Analysis; D013997:Time Factors; D055815:Young Adult