title: Comparative analysis of the Cosmed Quark b2 and K4b2 gas analysis systems during submaximal exercise.
abstract: OBJECTIVE
  The purpose of this study was to compare the Cosmed K4b2 portable gas analysis system with the Cosmed Quark b2 metabolic cart.
  
  
  METHODS
  Twenty-one subjects attended one testing session that consisted of duplicate measurements of gas volumes and concentrations using both Cosmed gas analysis systems at 3 treadmill work rates; 1) 80m x min(-1), 0% grade, 2) 80m x min(-1), 5% grade, and 3) 80m x min(-1), 10% grade. Subjects walked for 3 min at each rate with one of the gas analysis systems attached to the facemask. The order of the procedures was randomized so that one system was used during both phases (1st or 2nd) of each work rate.
  
  
  RESULTS
  The results indicated that oxygen consumption (VO2) was significantly higher in the K4b2 compared to the Quark at 80m x min(-1), 0% grade (14.3+/-1.2 vs 13.6+/-1.2ml x kg(-1) x min(-1), respectively), (p<0.01). The fractional concentration of oxygen in expired air was also significantly lower in the K4b2 at 80 m x min(-1), 0% grade and 80 m x min(-1), 10% grade (p<0.05). There were no significant differences between systems for minute ventilation or carbon dioxide production. Despite the small mean bias in mean VO2 values (0.5-1.0ml x kg-1 x min(-1) higher) in the K4b2, all individual values were within the limits of agreement (mean difference+/-2 SD) as determined by the Bland-Altman technique.
  
  
  CONCLUSIONS
  The findings show a minimal bias in respiratory and metabolic parameters during bi-pedal locomotor activities at low to moderate exercise intensities in the two gas analysis systems.
authors.affiliation: Division of Kinesiology and Health, University of Wyoming, Laramie, WY 72070, USA. eisenmann@uwyo.edu
authors.forename: J C
authors.initials: JC
authors.lastname: Eisenmann
authors.forename: N
authors.initials: N
authors.lastname: Brisko
authors.forename: D
authors.initials: D
authors.lastname: Shadrick
authors.forename: S
authors.initials: S
authors.lastname: Welsh
mesh_terms: D000328:Adult; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology*; D012123:Pulmonary Ventilation / Q000502:physiology*; D015203:Reproducibility of Results; D012129:Respiratory Function Tests / Q000295:instrumentation*; D013686:Telemetry / Q000295:instrumentation