Carbohydrate dependence during hard-intensity exercise in trained cyclists in the competitive season: importance of training status.
To test the hypothesis that intensive endurance training increases CHO utilisation during hard-intensity exercise, seven competitive road cyclists (Cy) performed three 50-min steady-state exercise tests on a cycle ergometer above their ventilatory threshold (+ 15 %) over the course of a cycling season (January [ET1], May [ET2] and September [ET3]). We compared the data with the baseline values of seven sedentary controls (Sed). CHO oxidation in Cy was higher in ET2 and ET3 than in ET1 (p < 0.05), was lower in ET3 than in ET2 (p < 0.05) and was higher in Cy than in Sed only in ET2 (p < 0.05). Lactate kinematics were lower in Cy than in Sed in all conditions (p < 0.05), but in Cy they were lower in ET2 than in ET1 and higher in ET3 than in ET2 (p < 0.05). Race performance was impaired and the overtraining score was increased at ET3 in comparison with ET2 (p < 0.05). We conclude that competitive cyclists increase CHO oxidation during hard-intensity exercise over the course of a season, but show a decline by the end of the season in association with the appearance of an overtraining state. Thus, well-trained cyclists develop a CHO dependence, which is modified with training status.
Manetta
J
J
Service Central de Physiologie Clinique, Centre d'Exploration et de Réadaptation des Anomalies Métaboliques et Musculaires, CHU Lapeyronie, Montpellier, France. jerome.manetta@free.fr
Brun
J F
JF
Maimoun
L
L
Galy
O
O
Coste
O
O
Maso
F
F
Raibaut
J L
JL
Benezis
C
C
Lac
G
G
Mercier
J
J
D000328:Adult; D000704:Analysis of Variance; D001642:Bicycling / Q000502:physiology*; D002153:Calorimetry, Indirect; D050260:Carbohydrate Metabolism; D016022:Case-Control Studies; D003163:Competitive Behavior / Q000502:physiology; D005080:Exercise Test; D006801:Humans; D007773:Lactates / Q000097:blood; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires
D007773:Lactates