The relationship between monocarboxylate transporters 1 and 4 expression in skeletal muscle and endurance performance in athletes
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The purpose of this study was to examine the relationship between skeletal muscle monocarboxylate transporters 1 and 4 (MCT1 and MCT4) expression, skeletal muscle oxidative capacity and endurance performance in trained cyclists. Ten well-trained cyclists (mean ± SD; age 24.4 ± 2.8 years, body mass 73.2 ± 8.3 kg, VO2max 58 ± 7 ml kg−1 min−1) completed three endurance performance tasks [incremental exercise test to exhaustion, 2 and 10 min time trial (TT)]. In addition, a muscle biopsy sample from the vastus lateralis muscle was analysed for MCT1 and MCT4 expression levels together with the activity of citrate synthase (CS) and 3-hydroxyacyl-CoA dehydrogenase (HAD). There was a tendency for VO2max and peak power output obtained in the incremental exercise test to be correlated with MCT1 (r = −0.71 to −0.74; P < 0.06), but not MCT4. The average power output (P average) in the 2 min TT was significantly correlated with MCT4 (r = −0.74; P < 0.05) and HAD (r = −0.92; P < 0.01). The P average in the 10 min TT was only correlated with CS activity (r = 0.68; P < 0.05). These results indicate the relationship between MCT1 and MCT4 as well as cycle TT performance may be influenced by the length and intensity of the task.
KeywordsAerobic Cycling Power Regulation Correlation
This study was financially supported by grants from the International Olympic Committee, the French Ministry of Sport and faculty (Medicine) research grants University of NSW, Sydney, Australia.
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