ISSN:
1439-6327
Keywords:
Oxygen uptake kinetics
;
Constantload exercise
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary The oxygen uptake kinetics during constant-load exercise when sitting on a bicycle ergometer were determined in 7 untrained subjects by measuring breath-by-breath $$\dot V_{{\text{O}}_{\text{2}} } $$ during continuous exercise to volitional exhaustion (mean endurance time=1160±172 s) at a pedal frequency of 70 revolutions · min−1. The power output, averaging 189,5 W, was set at 82.5% of that eliciting the individual $$\dot V_{{\text{O}}_{{\text{2}} {\text{max}}} } $$ during a 5 min incremental exercise test. Throughout the exercise period, the $$\dot V_{{\text{O}}_{\text{2}} } $$ kinetics could be appropriately described by a two-component exponential equation of the form: $$\dot V_{{\text{O}}_{\text{2}} } (t) = Y_a [1 - \exp ( - k_a t)] + Y_b [1 - \exp ( - k_b t)]$$ where $$\dot V_{{\text{O}}_{\text{2}} } $$ is net oxygen consumption andt the time from work onset. $$\dot V_{{\text{O}}_{\text{2}} } $$ measured at the end of exercise was close to $$\dot V_{{\text{O}}_{{\text{2}} {\text{max}}} } $$ (98% $$\dot V_{{\text{O}}_{{\text{2}} {\text{max}}} } $$ ) and the mean values ofY a ,k a ,Y b andk b amounted to 1195 ml O2 · min−1, 0.034s−1, 1562 ml O2 · min−1, and 0.005 s−1 respectively. The initial rate of increase in $$\dot V_{{\text{O}}_{\text{2}} } $$ predicted from the above equation is slower than that calculated, for the same work intensity, on the basis of the data obtained by Morton (1985) in trained subjects. For t〉480 s, however, the two models yield substantially equal results.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00636626
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