Muscle Characteristics and Substrate Energetics in Lifelong Endurance Athletes.

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Serval ID
serval:BIB_0F4646CE28EC
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Muscle Characteristics and Substrate Energetics in Lifelong Endurance Athletes.
Journal
Medicine and science in sports and exercise
Author(s)
Dubé J.J., Broskey N.T., Despines A.A., Stefanovic-Racic M., Toledo F.G., Goodpaster B.H., Amati F.
ISSN
1530-0315 (Electronic)
ISSN-L
0195-9131
Publication state
Published
Issued date
03/2016
Peer-reviewed
Oui
Volume
48
Number
3
Pages
472-480
Language
english
Notes
Publication types: Journal ArticlePublication Status: ppublish
Publication types: Comparative Study ; Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
Abstract
The goal of this study was to explore the effect of lifelong aerobic exercise (i.e., chronic training) on skeletal muscle substrate stores (intramyocellular triglyceride [IMTG] and glycogen), skeletal muscle phenotypes, and oxidative capacity (ox), in older endurance-trained master athletes (OA) compared with noncompetitive recreational younger (YA) athletes matched by frequency and mode of training.
Thirteen OA (64.8 ± 4.9 yr) exercising 5 times per week or more were compared with 14 YA (27.8 ± 4.9 yr) males and females. IMTG, glycogen, fiber types, succinate dehydrogenase, and capillarization were measured by immunohistochemistry in vastus lateralis biopsies. Fat-ox and carbohydrate (CHO)-ox were measured by indirect calorimetry before and after an insulin clamp and during a cycle ergometer graded maximal test.
V˙O2peak was lower in OA than YA. The OA had greater IMTG in all fiber types and lower glycogen stores than YA. This was reflected in greater proportion of type I and less type II fibers in OA. Type I fibers were similar in size, whereas type II fibers were smaller in OA compared with YA. Both groups had similar succinate dehydrogenase content. Numbers of capillaries per fiber were reduced in OA but with a higher number of capillaries per area. Metabolic flexibility and insulin sensitivity were similar in both groups. Exercise metabolic efficiency was higher in OA. At moderate exercise intensities, carbohydrate-ox was lower in OA but with similar Fat-ox.
Lifelong exercise is associated with higher IMTG content in all muscle fibers and higher metabolic efficiency during exercise that are not explained by differences in muscle fibers types and other muscle characteristics when comparing older with younger athletes matched by exercise mode and frequency.
Keywords
Adolescent, Adult, Age Factors, Aged, Athletes, Carbohydrate Metabolism, Cross-Sectional Studies, Exercise/physiology, Female, Glycogen/metabolism, Humans, Insulin Resistance, Lipid Metabolism, Male, Middle Aged, Muscle Fibers, Fast-Twitch/physiology, Muscle Fibers, Slow-Twitch/physiology, Muscle, Skeletal/anatomy & histology, Muscle, Skeletal/blood supply, Muscle, Skeletal/metabolism, Oxygen Consumption, Physical Endurance, Triglycerides/metabolism, Young Adult
Pubmed
Funding(s)
Swiss National Science Foundation / Careers / PZ00P3-149398
Swiss National Science Foundation / Careers / PZ00P3-126339
Create date
01/12/2015 17:31
Last modification date
20/01/2020 6:20
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