title: Intratest reliability and test-retest reproducibility of the oxygen uptake efficiency slope in healthy participants.
abstract: BACKGROUND
  The oxygen uptake efficiency slope (OUES) is a newer ventilatory exercise parameter, used in the evaluation of healthy participants and patients with cardiovascular disease. However, few data about the reliability and reproducibility of OUES are available. Our study assessed intratest reliability and test-retest reproducibility of OUES in healthy participants.
  
  
  METHODS
  Eighteen participants (age 28+/-6 years, BMI 22.1+/-1.9 kg/m, 10 men) performed two identical maximal exercise tests on a bicycle ergometer. To assess test-retest reproducibility, we performed Bland-Altman analysis and calculated the coefficient of repeatability of the main ventilatory variables.
  
  
  RESULTS
  OUES remained stable during the second part of the exercise test. Mean values varied 2.4+/-4.0% between OUES calculated at 70% (OUES70) and at 100% of exercise duration. Mean variation decreased to 1.4+/-2.3% when OUES was calculated at 90% of exercise duration (OUES90). The Bland-Altman 95% limits of agreement for OUES90 were +3 and -6%, those for OUES70 were +11 and -8%. The coefficient of repeatability for OUES was 597 ml/min or 18.7% of the average value of repeated OUES measurements. These results were similar to those of peak oxygen uptake and minute ventilation/carbon dioxide output. However, the test-retest reproducibility for submaximal-derived values of OUES was lower, as we noted higher coefficients of repeatability for OUES90 and OUES70, increasing up to 27% of the average of repeated values.
  
  
  CONCLUSIONS
  OUES shows excellent intratest reliability and has a test-retest reproducibility that is similar to that of peak oxygen uptake and minute ventilation/carbon dioxide output slope. However, its reproducibility becomes higher when it is calculated from increasing levels of achieved exercise intensity.
authors.affiliation: Department of Rehabilitation Sciences and Physiotherapy, Artevelde University College, Gent, Belgium. kine.van.laethem@telenet.be
authors.forename: Christophe
authors.initials: C
authors.lastname: Van Laethem
authors.forename: Johan
authors.initials: J
authors.lastname: De Sutter
authors.forename: Wim
authors.initials: W
authors.lastname: Peersman
authors.forename: Patrick
authors.initials: P
authors.lastname: Calders
mesh_terms: D000328:Adult; D005080:Exercise Test / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology*; D015203:Reproducibility of Results; D015656:Respiratory Mechanics