title: Critical power testing or self-selected cycling: Which one is the best predictor of maximal metabolic steady-state?
abstract: Critical power (CP) demarcates the boundary between heavy and very heavy exercise intensity domains, and therefore, the power output (PO) that can be sustained at the maximal metabolic steady-state during constant-PO exercise (i.e., maximal lactate steady-state (MLSS)). However, the estimated CP does not always reflect a sustainable intensity of exercise, where blood lactate concentration ([La]) and oxygen uptake (V˙O2) reach a plateau.
  
  
  OBJECTIVE
  To test cyclists' ability to predict their highest PO associated with metabolic steady-state based on their own perception of effort.
  
  
  METHODS
  Repeated measures.
  
  
  METHODS
  Thirteen healthy young cyclists (26±3years; 69.0±9.2kg; 174±10cm) were tested. Five time-to-exhaustion trials were used to derive CP based on a 2-parameter hyperbolic model (CPHYP). Participants performed two 30-min rides at a self-selected PO that they considered their highest sustainable exercise intensity (CPSELF). Additionally, MLSS was determined as the highest PO at which variation in [La] ≤1.0mmolL-1between the 10th and 30th min was observed during a 30-min ride.
  
  
  RESULTS
  Mean PO at CPSELF(233±42W) was similar (p>0.05) to MLSS (233±41W), whereas CPHYP(253±44W) consistently overestimated (p<0.05) the PO associated to metabolic steady-state. The limits of agreement (LOA) between MLSS and CPSELFwere -20 to +20W (bias=0W, p>0.05), whereas the LOA between CPHYPand CPSELFwere -40 to 0W (bias=-20W, p<0.05). CPSELFand MLSS presented similar (p>0.05) metabolic response (i.e., V˙O2, [La], and HR).
  
  
  CONCLUSIONS
  Compared to CPHYP, CPSELFmay offer a more precise approach to predict the constant-PO associated with maximal physiological steady-state.
authors.affiliation: Faculty of Kinesiology, University of Calgary, Canada.
authors.forename: Felipe
authors.initials: F
authors.lastname: Mattioni Maturana
authors.affiliation: School of Kinesiology, The University of Western Ontario, Canada.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Keir
authors.affiliation: School of Kinesiology, The University of Western Ontario, Canada.
authors.forename: Kaitlin M
authors.initials: KM
authors.lastname: McLay
authors.affiliation: Faculty of Kinesiology, University of Calgary, Canada. Electronic address: jmmurias@ucalgary.ca.
authors.forename: Juan M
authors.initials: JM
authors.lastname: Murias
mesh_terms: D000328:Adult; D015308:Anaerobic Threshold / Q000502:physiology*; D054874:Athletic Performance / Q000502:physiology; D001642:Bicycling / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D010101:Oxygen Consumption; D013997:Time Factors; D055815:Young Adult
keywords: Exercise intensity thresholds; Maximal lactate steady-state; Perceived exertion; Power-time relationship