Influence of two pedalling rate conditions on mechanical output and physiological responses during all-out intermittent exercise |
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Authors: | Email author" target="_blank">Sylvain?DorelEmail author Muriel?Bourdin Emmanuel?Van?Praagh Jean-René?Lacour Christophe?André?Hautier |
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Institution: | (1) Laboratoire de Physiologie de l'Exercice GIP Exercise-Sport-Santé, Faculté de Médecine Lyon Sud, BP 12, 69921, Oullins Cedex, France,;(2) Laboratoire de Biologie des Activités Physiques et Sportives, Université Blaise-Pascal Université d'Auvergne, BP 104, 63172, Aubière Cedex, France, |
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Abstract: | The purpose of this study was to investigate the effect of two cycling velocities on power output and concomitant metabolic
and cardiorespiratory responses to repeated all-out exercises. Mean power output (P
m), total work (W
tot), total oxygen consumption (VO2tot) and blood lactate accumulation (ΔLa]b) were evaluated in 13 male subjects who performed two series of twelve 5-s bouts of sprint cycling. Recovery periods of 45-s
were allowed between trials. One series was executed at optimal velocity (V
opt: velocity for greatest power) and the other one at 50% V
opt (0.5V
opt). Velocities obtained in these conditions were Vopt=116.6 (4.7) rpm; 0.5Vopt=60.6 (4.9) rpm. After a phase of adaptation in oxygen uptake in the first part of the series, the data from the 6th to the
12th sprint were as follows: P
m, 924.6 (73.9) versus 689.2 (61.8) W; W
tot, 29.95 (4.14) versus 22.04 (3.17) kJ; VO2tot, 12.80 (1.36) versus 10.58 (1.37) l; ΔLa]b, 2.72 (1.22) versus 0.64 (0.79) mmol.l−1, respectively (P<0.001). Both W
tot and VO2tot were consistently higher at optimal velocity (+21 and +35.8%, respectively). The present findings demonstrate that during
intermittent short-term all-out exercise requiring maximal activation, the energy turnover is not necessarily maximal. It
depends on muscle contraction velocity. The increase, lower than expected, in metabolic response from 0.5V
opt to V
opt suggests also that mechanical efficiency is higher at V
opt.
Electronic Publication |
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Keywords: | Blood lactate accumulation Oxygen uptake Pedalling frequency Supramaximal exercise Work |
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