Functional properties of human muscle fibers after short-term resistance exercise training

Department of Exercise and Sport Science, Oregon State University, Corvallis, Oregon 97331 The aim of this study was to assess the relationships between human muscle fiber hypertrophy, protein isoform content, and maximal Ca 2+ -activated contractile function following a short-term period of resista...

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Published inAmerican journal of physiology. Regulatory, integrative and comparative physiology Vol. 283; no. 2; pp. 408 - R416
Main Authors Widrick, Jeffrey J, Stelzer, Julian E, Shoepe, Todd C, Garner, Dena P
Format Journal Article
LanguageEnglish
Published United States 01.08.2002
Subjects
Adaptation, Physiological
Adult
Biomechanical Phenomena
Biopsy
Body Composition - physiology
Calcium - physiology
Exercise - physiology
Humans
In Vitro Techniques
Male
Muscle Contraction - physiology
Muscle Fibers, Fast-Twitch - chemistry
Muscle Fibers, Fast-Twitch - physiology
Muscle Fibers, Slow-Twitch - chemistry
Muscle Fibers, Slow-Twitch - physiology
Muscle, Skeletal - chemistry
Muscle, Skeletal - physiology
Myosins - analysis
Protein Isoforms - analysis
Stress, Mechanical
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Summary:Department of Exercise and Sport Science, Oregon State University, Corvallis, Oregon 97331 The aim of this study was to assess the relationships between human muscle fiber hypertrophy, protein isoform content, and maximal Ca 2+ -activated contractile function following a short-term period of resistance exercise training. Six male subjects (age 27 ± 2   yr) participated in a 12-wk progressive resistance exercise training program that increased voluntary lower limb extension strength by >60%. Single chemically skinned fibers were prepared from pre- and posttraining vastus lateralis muscle biopsies. Training increased the cross-sectional area (CSA) and peak Ca 2+ -activated force (P o ) of fibers containing type I, IIa, or IIa/IIx myosin heavy chain by 30-40% without affecting fiber-specific force (P o /CSA) or unloaded shortening velocity (V o ). Absolute fiber peak power rose as a result of the increase in P o , whereas power normalized to fiber volume was unchanged. At the level of the cross bridge, the effects of short-term resistance training were quantitative (fiber hypertrophy and proportional increases in fiber P o and absolute power) rather than qualitative (no change in P o /CSA, V o , or power/fiber volume). resistance training; strength training; muscle hypertrophy; myosin heavy chain; contractile properties
Bibliography:ObjectType-Article-2
SourceType-Scholarly Journals-1
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ISSN:0363-6119
1522-1490
DOI:10.1152/ajpregu.00120.2002