On the determination of ventilatory threshold and respiratory compensation point via respiratory frequency.
This study examined the validity of a quantitative respiratory frequency (f(R)) analysis to detect the ventilatory threshold (theta(Vent)) and respiratory compensation point (RCP). Thirty-six amateur competitive cyclists completed a maximal graded exercise test on an electromagnetically-braked cycle ergometer. theta(Vent) and RCP were determined using multiple gas exchange criteria and by f(R) analysis (theta(Vent)f(R) and RCP(f(R))), employing an iterative least-squares linear regression technique. Fifteen subjects were excluded from the analyses due to a low signal-to-noise ratio and/or high risk for pseudo-threshold resulting from hyperventilation early in the exercise protocol. A Bland-Altman procedure for inter-analysis comparison completed on the remaining participants' data (n=21; age=29+/-7 years; height=177+/-9 cm; weight=76.0+/-15.8 kg; VO(2max)=4.415+/-0.971 lmin(-1); 58.7+/-10.7 ml kg(-1) min(-1)) revealed mean bias+/-95% Limits of Agreement (LOA) of 1.53+/-50.2 W for theta(Vent) and theta(Vent)f(R). The same inter-anlysis comparison (n=21) for RCP and RCP(f(R)) resulted in a mean bias+/-LOA of 12.6+/-26.9 W. The analysis techniques in the present investigation revealed substantial limits of agreement and/or bias for all estimations, and these data indicated f(R) analyses were unsatisfactory to determine theta(Vent) and RCP in trained cyclists.
Cannon
D T
DT
School of Exercise and Nutritional Sciences, San Diego State University, San Diego, CA, USA. d.t.cannon08@leeds.ac.uk
Kolkhorst
F W
FW
Buono
M J
MJ
D000328:Adult; D015982:Bias; D001642:Bicycling; D055590:Electromagnetic Phenomena; D005080:Exercise Test / Q000379:methods* / Q000592:standards; D005260:Female; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D016014:Linear Models; D008297:Male; D011659:Pulmonary Gas Exchange; D012123:Pulmonary Ventilation; D055815:Young Adult
D019344:Lactic Acid