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2012, Number 3

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Rev Hosp Jua Mex 2012; 79 (3)

Comparison of modelling techniques used to characterize moderate and heavy phase two recovery VO2 kinetics in young men

Padilla-Pérez J

Language: English
References: 23
Page: 159-173
PDF size: 450.43 Kb.


ABSTRACT

The analysis of the phase two pulmonary O2 uptake (Φ2 VO2) off-transient response during moderate (Mod)- and heavy(Hvy)- intensity constant-load post-exercise recovery was assessed, in young healthy male volunteers (n = 8; mean ± SD: 25 ± 2 yrs). Subjects completed an initial incremental ramp test (25 W•min-1) to volitional fatigue from which the ventilatory threshold (VET) and work rates corresponding to 80%VET (ModRel) and 120%VET (HvyRel) (SubmaximalExercise) were identified. Also, it was selected an absolute work rate of 50 W (ModAbs). Off step-transitions in work rate were initiated from a baseline of 1 min (BSL) end exercise intensity without warning to the subject. Each off transition lasted 6 min (6minRecExerc) and 4-6 transitions were performed at each intensity. The VO2 response was measured breath-by-breath at baseline and throughout each transition. Data were filtered, interpolated to 1-s intervals and ensemble-averaged to yield a single response profile for each subject and intensity. The averaged response for each subject was fit with a one- (1C), two- (2C), and three-component (3C) exponential model by using different fitting windows (→), and parameter estimates BSL, time delay (TD), time constant (τ), amplitude (AMP) were determined for each component. Best fitting model was identified based on the Fisher’s test and/or parameter’s physiological meaning. ModAbs was well described by either 2C,7PBSL →6minRecExerc kinetically isolateting off Φ2 VO2 (τΦ2 VO2 = 25 ± 8 s) or 1C,4P0.3333 min →6minRecExerc(omitting Φ1 VO2) kinetically semi-isolated offΦ2 VO2 (τ2 = 28 ± 4 s). The 2C,7P0.3333 min →6minRecExerc kinetically semi-isolated off Φ2VO2 for either ModRel (τ2 = 22.5 ± 4.2 s) or HvyRel (τ2 = 22.8 ± 6 s) (τ2off (omitting f1 O2) SubmaxExerc = 24.42 ± 5.30 s. These best-fit models were those that well-described τ2 VO2 off-transient kinetics (τ2) for submaximal exercise in young men.


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