title: Reproducibility of endurance performance on a treadmill using a preloaded time trial.
abstract: OBJECTIVE
  The purpose of this study was to establish a highly reproducible test to measure endurance performance in runners.
  
  
  METHODS
  We evaluated the reproducibility of endurance performance during a 10-km time trial performed on a treadmill after a 90-min preload run at 65% of maximal oxygen uptake VO2max). After screening and a practice test, eight endurance runners (4 men, 4 women, 33.4 +/- 10.1 yr, VO2max = 60.3 +/- 6.3 mL x kg(-1) x min(-1) in men and 51.8 +/- 2.2 mL x kg(-1) x min(-1) in women, mean +/- SD) completed two preloaded time trial tests spaced 3-4 wk apart in men and one menstrual cycle apart in women. A high-carbohydrate diet (15% protein, 10% fat, 75% carbohydrate) was provided the day before both tests.
  
  
  RESULTS
  Runners completed time trial 1 and time trial 2 in 45:41 +/- 4:45 and 45:24 +/- 5:03 min:s, respectively (43:29 +/- 5:02 and 43:12 +/- 5:14 min:s for men and 47:53 +/- 3:47 and 47:35 +/- 4:23 min:s for women, trials 1 and 2, respectively). The within-subject coefficient of variation for 10-km time was 1.00% +/- 0.25% (point estimate +/- estimated standard error) (0.54% +/- 0.19% for men and 1.26% +/- 0.45% for women).
  
  
  CONCLUSIONS
  These results suggest that performance measured as time to complete a 10-km time trial on a treadmill after a 90-min preload is extremely reliable and may be useful for future research assessing the effect of diet, ergogenic substances, or training methods on endurance running performance.
authors.affiliation: Department of Human Studies, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA.
authors.forename: Ryan D
authors.initials: RD
authors.lastname: Russell
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Redmann
authors.forename: Eric
authors.initials: E
authors.lastname: Ravussin
authors.forename: Gary R
authors.initials: GR
authors.lastname: Hunter
authors.forename: D Enette
authors.initials: DE
authors.lastname: Larson-Meyer
mesh_terms: D000293:Adolescent; D000328:Adult; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010807:Physical Endurance / Q000502:physiology*; D015203:Reproducibility of Results; D012420:Running / Q000502:physiology*; D013996:Time and Motion Studies; D014481:United States
chemical_list: D004040:Dietary Carbohydrates