, Volume 112, Issue 5, pp 1689-1697
Date: 31 Aug 2011

Effects of aerobic fitness on oxygen uptake kinetics in heavy intensity swimming

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access

Abstract

This study aimed to characterise both the \( \dot{V}{\text{O}}_{2} \) kinetics within constant heavy-intensity swimming exercise, and to assess the relationships between \( \dot{V}{\text{O}}_{2} \) kinetics and other parameters of aerobic fitness, in well-trained swimmers. On separate days, 21 male swimmers completed: (1) an incremental swimming test to determine their maximal oxygen uptake \( (\dot{V}{\text{O}}_{2\max } ) \) , first ventilatory threshold (VT), and the velocity associated with \( \dot{V}{\text{O}}_{2\max } \) \( (v\dot{V}{\text{O}}_{2\max } ) \) and (2) two square-wave transitions from rest to heavy-intensity exercise, to determine their \( \dot{V}{\text{O}}_{2} \) kinetics. All the tests involved breath-by-breath analysis of freestyle swimming using a swimming snorkel. \( \dot{V}{\text{O}}_{2} \) kinetics was modelled with two exponential functions. The mean values for the incremental test were 56.0 ± 6.0 ml min−1 kg−1, 1.45 ± 0.08 m s−1; and 42.1 ± 5.7 ml min−1 kg−1 for \( \dot{V}{\text{O}}_{2\max } \) , \( v\dot{V}{\text{O}}_{2\max } \) and VT, respectively. For the square-wave transition, the time constant of the primary phase (τp) averaged 17.3 ± 5.4 s and the relevant slow component (Asc) averaged 4.8 ± 2.9 ml min−1 kg−1 [representing 8.9% of the end-exercise \( \dot{V}{\text{O}}_{2} \) (%Asc)]. τp was correlated with \( v\dot{V}{\text{O}}_{2\max } \) (r = −0.55, P = 0.01), but not with either \( \dot{V}{\text{O}}_{{ 2 {\text{max}}}} \) (r = 0.05, ns) or VT (r = 0.14, ns). The %Asc did not correlate with either \( \dot{V}{\text{O}}_{{ 2 {\text{max}}}} \) (r = −0.14, ns) or \( v\dot{V}{\text{O}}_{2\max } \) (r = 0.06, ns), but was inversely related with VT (r = −0.61, P < 0.01). This study was the first to describe the \( \dot{V}{\text{O}}_{2}\) kinetics in heavy-intensity swimming using specific swimming exercise and appropriate methods. As has been demonstrated in cycling, faster \( \dot{V}{\text{O}}_{2} \) kinetics allow higher aerobic power outputs to be attained. The slow component seems to be reduced in swimmers with higher ventilatory thresholds.

Communicated by David C. Poole.