Substrate use and biochemical response to a 3,211-km bicycle tour in trained cyclists

Dustin R. Slivka; Charles L. Dumke; Walter S. Hailes; John S. Cuddy; Brent C. Ruby

doi:10.1007/s00421-011-2129-3

Substrate use and biochemical response to a 3,211-km bicycle tour in trained cyclists

Dustin R. Slivka, Charles L. Dumke, Walter S. Hailes, John S. Cuddy, Brent C. Ruby

Integrative Physiology and Athletic Training

University of Montana

Research output: Contribution to journal › Review article › peer-review

11 Scopus citations

Abstract

The purpose of this study was to assess the physiological adaptations in physically fit individuals to a period of intensified training. Ten trained males cycled outdoors ∼170 km day-1 on 19 out of 21 days. Expired gas was collected on days 1 and 21 during maximal graded exercise and used for the determination of gross efficiency and whole body substrate use. Muscle biopsies were obtained before and after exercise on days 2 and 22 for the determination of mtDNA/gDNA ratio, gene expression, metabolic enzyme activity and glycogen use. Muscle glycogen before and after exercise, fat oxidation, and gross efficiency increased, carbohydrate oxidation decreased (p<0.05), and VO _2max did not change over the 21 days of training. Citrate synthase (CS), -hydroxyacyl CoA dehydrogenase (-HAD) and cytochrome c oxidase (COX) enzyme activity did not change with training. CS and -HAD mRNA did not change with acute exercise or training. COX (subunit IV) mRNA increased with acute exercise (p<0.05) but did not change over the 21 days. PGC-1α mRNA increased with acute exercise, but did not increase to the same degree on day 22 as it did on day 2 (p<0.05). UCP3 mRNA decreased with training (p<0.05). Acute exercise caused an increase in mitofusin2 (MFN2) mRNA (p<0.05) and a trend for an increase in mtDNA/gDNA ratio (p = 0.057). However, training did not affect MFN2 mRNA or mtDNA/gDNA ratio. In response to 3,211 km of cycling, changes in substrate use and gross efficiency appear to be more profound than mitochondrial adaptations in trained individuals.

Original language	English
Pages (from-to)	1621-1630
Number of pages	10
Journal	European Journal of Applied Physiology
Volume	112
Issue number	5
DOIs	https://doi.org/10.1007/s00421-011-2129-3
State	Published - May 2012

Keywords

Cycling
Efficiency
Gene expression
Metabolic enzymes
MtDNA
Training adaptation

UN SDGs

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10.1007/s00421-011-2129-3

Cite this

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title = "Substrate use and biochemical response to a 3,211-km bicycle tour in trained cyclists",

abstract = "The purpose of this study was to assess the physiological adaptations in physically fit individuals to a period of intensified training. Ten trained males cycled outdoors ∼170 km day-1 on 19 out of 21 days. Expired gas was collected on days 1 and 21 during maximal graded exercise and used for the determination of gross efficiency and whole body substrate use. Muscle biopsies were obtained before and after exercise on days 2 and 22 for the determination of mtDNA/gDNA ratio, gene expression, metabolic enzyme activity and glycogen use. Muscle glycogen before and after exercise, fat oxidation, and gross efficiency increased, carbohydrate oxidation decreased (p<0.05), and VO 2max did not change over the 21 days of training. Citrate synthase (CS), -hydroxyacyl CoA dehydrogenase (-HAD) and cytochrome c oxidase (COX) enzyme activity did not change with training. CS and -HAD mRNA did not change with acute exercise or training. COX (subunit IV) mRNA increased with acute exercise (p<0.05) but did not change over the 21 days. PGC-1α mRNA increased with acute exercise, but did not increase to the same degree on day 22 as it did on day 2 (p<0.05). UCP3 mRNA decreased with training (p<0.05). Acute exercise caused an increase in mitofusin2 (MFN2) mRNA (p<0.05) and a trend for an increase in mtDNA/gDNA ratio (p = 0.057). However, training did not affect MFN2 mRNA or mtDNA/gDNA ratio. In response to 3,211 km of cycling, changes in substrate use and gross efficiency appear to be more profound than mitochondrial adaptations in trained individuals.",

keywords = "Cycling, Efficiency, Gene expression, Metabolic enzymes, MtDNA, Training adaptation",

author = "Slivka, {Dustin R.} and Dumke, {Charles L.} and Hailes, {Walter S.} and Cuddy, {John S.} and Ruby, {Brent C.}",

note = "Funding Information: Acknowledgments The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of Air Force Research laboratory or the U.S. government. Sponsored by Air Force Research Laboratory under agreement number FA5650-06-2-6740 and the University of Montana Grant program. We would like to acknowledge the assistance of the Molecular Biology Core Facility of The University of Montana supported in part by National Center for Research Resources Grants P20RR017670 and P20RR015583.",

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AU - Hailes, Walter S.

AU - Cuddy, John S.

AU - Ruby, Brent C.

N1 - Funding Information: Acknowledgments The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of Air Force Research laboratory or the U.S. government. Sponsored by Air Force Research Laboratory under agreement number FA5650-06-2-6740 and the University of Montana Grant program. We would like to acknowledge the assistance of the Molecular Biology Core Facility of The University of Montana supported in part by National Center for Research Resources Grants P20RR017670 and P20RR015583.

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N2 - The purpose of this study was to assess the physiological adaptations in physically fit individuals to a period of intensified training. Ten trained males cycled outdoors ∼170 km day-1 on 19 out of 21 days. Expired gas was collected on days 1 and 21 during maximal graded exercise and used for the determination of gross efficiency and whole body substrate use. Muscle biopsies were obtained before and after exercise on days 2 and 22 for the determination of mtDNA/gDNA ratio, gene expression, metabolic enzyme activity and glycogen use. Muscle glycogen before and after exercise, fat oxidation, and gross efficiency increased, carbohydrate oxidation decreased (p<0.05), and VO 2max did not change over the 21 days of training. Citrate synthase (CS), -hydroxyacyl CoA dehydrogenase (-HAD) and cytochrome c oxidase (COX) enzyme activity did not change with training. CS and -HAD mRNA did not change with acute exercise or training. COX (subunit IV) mRNA increased with acute exercise (p<0.05) but did not change over the 21 days. PGC-1α mRNA increased with acute exercise, but did not increase to the same degree on day 22 as it did on day 2 (p<0.05). UCP3 mRNA decreased with training (p<0.05). Acute exercise caused an increase in mitofusin2 (MFN2) mRNA (p<0.05) and a trend for an increase in mtDNA/gDNA ratio (p = 0.057). However, training did not affect MFN2 mRNA or mtDNA/gDNA ratio. In response to 3,211 km of cycling, changes in substrate use and gross efficiency appear to be more profound than mitochondrial adaptations in trained individuals.

AB - The purpose of this study was to assess the physiological adaptations in physically fit individuals to a period of intensified training. Ten trained males cycled outdoors ∼170 km day-1 on 19 out of 21 days. Expired gas was collected on days 1 and 21 during maximal graded exercise and used for the determination of gross efficiency and whole body substrate use. Muscle biopsies were obtained before and after exercise on days 2 and 22 for the determination of mtDNA/gDNA ratio, gene expression, metabolic enzyme activity and glycogen use. Muscle glycogen before and after exercise, fat oxidation, and gross efficiency increased, carbohydrate oxidation decreased (p<0.05), and VO 2max did not change over the 21 days of training. Citrate synthase (CS), -hydroxyacyl CoA dehydrogenase (-HAD) and cytochrome c oxidase (COX) enzyme activity did not change with training. CS and -HAD mRNA did not change with acute exercise or training. COX (subunit IV) mRNA increased with acute exercise (p<0.05) but did not change over the 21 days. PGC-1α mRNA increased with acute exercise, but did not increase to the same degree on day 22 as it did on day 2 (p<0.05). UCP3 mRNA decreased with training (p<0.05). Acute exercise caused an increase in mitofusin2 (MFN2) mRNA (p<0.05) and a trend for an increase in mtDNA/gDNA ratio (p = 0.057). However, training did not affect MFN2 mRNA or mtDNA/gDNA ratio. In response to 3,211 km of cycling, changes in substrate use and gross efficiency appear to be more profound than mitochondrial adaptations in trained individuals.

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KW - Efficiency

KW - Gene expression

KW - Metabolic enzymes

KW - MtDNA

KW - Training adaptation

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JF - European Journal of Applied Physiology

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ER -

Substrate use and biochemical response to a 3,211-km bicycle tour in trained cyclists

Abstract

Keywords

UN SDGs

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