Biomaterial Database

Changes in muscle fiber size and composition in response to heavy-resistance exercise. 1991

A E Mikesky, and C J Giddings, and W Matthews, and W J Gonyea

Department of Cell Biology and Neuroscience, University of Texas Southwestern Medical Center, Dallas 75235-9039.

Progressive resistance exercise was used to induce hypertrophy in the right palmaris longus muscle (PLM) of 16 cats. The left PLM served as the non-exercised intra-animal control. After an average 150 +/- 26.6 wk of training, left and right PLMs were removed and weighed. Muscle fibers were typed using standard histochemical techniques. Mean fiber cross-sectional area, connective tissue content, and muscle fiber length were determined. The right exercised PLM demonstrated a 24.2 +/- 6.9% increase in muscle mass. Mean muscle fiber cross-sectional area increased 11.0 +/- 7.3% in the exercised muscles. No change in connective tissue content, fiber length, or fiber type composition was observed. The results show that increases in muscle fiber cross-sectional area do not account for all the observed increases in muscle mass, and that other mechanisms, such as muscle fiber hyperplasia, may play a role in contributing to muscle mass increases.

UI	MeSH Term	Description	Entries
D006965	Hyperplasia	An increase in the number of cells in a tissue or organ without tumor formation. It differs from HYPERTROPHY, which is an increase in bulk without an increase in the number of cells.	Hyperplasias
D006984	Hypertrophy	General increase in bulk of a part or organ due to CELL ENLARGEMENT and accumulation of FLUIDS AND SECRETIONS, not due to tumor formation, nor to an increase in the number of cells (HYPERPLASIA).	Hypertrophies
D009132	Muscles	Contractile tissue that produces movement in animals.	Muscle Tissue,Muscle,Muscle Tissues,Tissue, Muscle,Tissues, Muscle
D010805	Physical Conditioning, Animal	Diet modification and physical exercise to improve the ability of animals to perform physical activities.	Animal Physical Conditioning,Animal Physical Conditionings,Conditioning, Animal Physical,Conditionings, Animal Physical,Physical Conditionings, Animal
D002415	Cats	The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)	Felis catus,Felis domesticus,Domestic Cats,Felis domestica,Felis sylvestris catus,Cat,Cat, Domestic,Cats, Domestic,Domestic Cat
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D014891	Weight Lifting	A sport in which weights are lifted competitively or as an exercise.	Lifting, Weight,Liftings, Weight,Weight Liftings