title: Are oxygen uptake kinetics modified when using a respiratory snorkel?
abstract: OBJECTIVE
  The aim of this study was to compare VO2 kinetics during constant power cycle exercise measured using a conventional facemask (CM) or a respiratory snorkel (RS) designed for breath-by-breath analysis in swimming.
  
  
  METHODS
  VO2 kinetics parameters-obtained using CM or RS, in randomized counterbalanced order-were compared in 10 trained triathletes performing two submaximal heavy-intensity cycling square-wave transitions. These VO2 kinetics parameters (ie, time delay: td1, td2; time constant: τ1, τ2; amplitude: A1, A2, for the primary phase and slow component, respectively) were modeled using a double exponential function. In the case of the RS data, this model incorporated an individually determined snorkel delay (ISD).
  
  
  RESULTS
  Only td1 (8.9 ± 3.0 vs 13.8 ± 1.8 s, P < .01) differed between CM and RS, whereas all other parameters were not different (τ1 = 24.7 ± 7.6 vs 21.1 ± 6.3 s; A1 = 39.4 ± 5.3 vs 36.8 ± 5.1 mL x min(-1) x kg(-1); td2 = 107.5 ± 87.4 vs 183.5 ± 75.9 s; A2' (relevant slow component amplitude) = 2.6 ± 2.4 vs 3.1 ± 2.6 mL x min(-1) x kg(-1) for CM and RS, respectively).
  
  
  CONCLUSIONS
  Although there can be a small mixture of breaths allowed by the volume of the snorkel in the transition to exercise, this does not appear to significantly influence the results. Therefore, given the use of an ISD, the RS is a valid instrument for the determination of VO2 kinetics within submaximal exercise.
authors.affiliation: Department of Sport Sciences, Faculty of Human Kinetics, Technical University of Lisbon, Portugal.
authors.forename: Joana F
authors.initials: JF
authors.lastname: Reis
authors.forename: Gregoire P
authors.initials: GP
authors.lastname: Millet
authors.forename: Davide
authors.initials: D
authors.lastname: Malatesta
authors.forename: Belle
authors.initials: B
authors.lastname: Roels
authors.forename: Fabio
authors.initials: F
authors.lastname: Borrani
authors.forename: Veronica E
authors.initials: VE
authors.lastname: Vleck
authors.forename: Francisco B
authors.initials: FB
authors.lastname: Alves
mesh_terms: D000328:Adult; D005080:Exercise Test; D006801:Humans; D007700:Kinetics; D008297:Male; D008397:Masks; D010101:Oxygen Consumption / Q000502:physiology*; D012044:Regression Analysis; D012129:Respiratory Function Tests; D013550:Swimming / Q000502:physiology*