Strength exercise improves muscle mass and hepatic insulin sensitivity in obese youth.

Strength exercise improves muscle mass and hepatic insulin sensitivity in obese youth.

MedLine Citation:	PMID: 20351587 Owner: NLM Status: MEDLINE
Abstract/OtherAbstract:	INTRODUCTION: Data on the metabolic effects of resistance exercise (strength training) in adolescents are limited. PURPOSE: The objective of this study was to determine whether a controlled resistance exercise program without dietary intervention or weight loss reduces body fat accumulation, increases lean body mass, and improves insulin sensitivity and glucose metabolism in sedentary obese Hispanic adolescents. METHODS: Twelve obese adolescents (age = 15.5 ± 0.5 yr, body mass index = 35.3 ± 0.8 kg·m; 40.8% ± 1.5% body fat) completed a 12-wk resistance exercise program (two times 1 h·wk, exercising all major muscle groups). At baseline and on completion of the program, body composition was measured by dual-energy x-ray absorptiometry, abdominal fat distribution was measured by magnetic resonance imaging, hepatic and intramyocellular fat was measured by magnetic resonance spectroscopy, peripheral insulin sensitivity was measured by the stable-label intravenous glucose tolerance test, and hepatic insulin sensitivity was measured by the hepatic insulin sensitivity index = 1000/(GPR × fasting insulin). Glucose production rate (GPR), gluconeogenesis, and glycogenolysis were quantified using stable isotope gas chromatography/mass spectrometry techniques. RESULTS: All participants were normoglycemic. The exercise program resulted in significant strength gain in both upper and lower body muscle groups. Body weight increased from 97.0 ± 3.8 to 99.6 ± 4.2 kg (P < 0.01). The major part (∼80%) was accounted for by increased lean body mass (55.7 ± 2.8 to 57.9 ± 3.0 kg, P ≤ 0.01). Total, visceral, hepatic, and intramyocellular fat contents remained unchanged. Hepatic insulin sensitivity increased by 24% ± 9% (P < 0.05), whereas peripheral insulin sensitivity did not change significantly. GPR decreased by 8% ± 1% (P < 0.01) because of a 12% ± 5% decrease in glycogenolysis (P < 0.05). CONCLUSIONS: We conclude that a controlled resistance exercise program without weight loss increases strength and lean body mass, improves hepatic insulin sensitivity, and decreases GPR without affecting total fat mass or visceral, hepatic, and intramyocellular fat contents.

Authors:	Gert-Jan Van Der Heijden; Zhiyue J Wang; Zili Chu; Gianna Toffolo; Erica Manesso; Pieter J J Sauer; Agneta L Sunehag
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Publication Detail:	Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.
Journal Detail:	Title: Medicine and science in sports and exercise Volume: 42 ISSN: 1530-0315 ISO Abbreviation: Med Sci Sports Exerc Publication Date: 2010 Nov
Date Detail:	Created Date: 2010-10-22 Completed Date: 2011-02-03 Revised Date: 2011-11-01
Medline Journal Info:	Nlm Unique ID: 8005433 Medline TA: Med Sci Sports Exerc Country: United States
Other Details:	Languages: eng Pagination: 1973-80 Citation Subset: IM; S
Affiliation:	Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA.
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MeSH Terms
Descriptor/Qualifier:	Adipose Tissue / metabolism Adolescent Female Humans Insulin / physiology* Liver / metabolism* Male Muscles / physiology* Obesity* Resistance Training*
Grant Support
ID/Acronym/Agency:	M01-RR-00188-34/RR/NCRR NIH HHS; R01 HD044609/HD/NICHD NIH HHS; R01 HD044609-01A2/HD/NICHD NIH HHS
Chemical
Reg. No./Substance:	11061-68-0/Insulin

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