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Erschienen in:
01.10.2007 | Original Article
Improvement of \(\dot{V}\hbox{O}_{2 \max},\) by cardiac output and oxygen extraction adaptation during intermittent versus continuous endurance training
Erschienen in: European Journal of Applied Physiology | Ausgabe 3/2007
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Improvement of exercise capacity by continuous (CT) versus interval training (IT) remains debated. We tested the hypothesis that CT and IT might improve peripheral and/or central adaptations, respectively, by randomly assigning 10 healthy subjects to two periods of 24 trainings sessions over 8 weeks in a cross-over design, separated by 12 weeks of detraining. Maximal oxygen uptake \((\dot{V}\hbox{O}_{2 \max}),\) cardiac output \((\dot{Q}_{{\max}})\) and maximal arteriovenous oxygen difference \((D_{{\rm a} - {\bar{\rm v}}} \hbox{O}_{2\max})\) were obtained during an exhaustive incremental test before and after each training period. \(\dot{V}\hbox{O}_{2\max}\) and \(\dot{Q}_{{\max}}\) increased only after IT (from 26.3 ± 1.6 to 35.2 ± 3.8 ml min−1 kg−1 and from 17.5 ± 1.3 to 19.5 ± 1.8 l min−1, respectively; P < 0.01). \(D_{{\rm a} - {\bar{\rm v}}} \hbox{O}_{2\max}\) increased after both protocols (from 11.0 ± 0.8 to 12.7 ± 1.0; P < 0.01 and from 11.0 ± 0.8 to 12.1 ± 1.0 ml 100 ml−1, P < 0.05 in CT and IT, respectively). At submaximal intensity a significant rightward shift of the \(\dot{Q}/D_{{\rm a} - {\bar{\rm v}}}\hbox{O}_{2}\) relationship appeared only after CT. These results suggest that in isoenergetic training, central and peripheral adaptations in oxygen transport and utilization are training-modality dependant. IT improves both central and peripheral components of \(\dot{V}\hbox{O}_{2\max}\) whereas CT is mainly associated with greater oxygen extraction.