Effect of growth and training on muscle adaptation in Thoroughbred horses.
Am J Vet Res
; 63(10): 1408-12, 2002 Oct.
Article
em En
| MEDLINE
| ID: mdl-12371768
ABSTRACT
OBJECTIVE:
To determine the effect of growth and training on metabolic properties in muscle fibers of the gluteus medius muscle in adolescent Thoroughbred horses. ANIMALS Twenty 2-year-old Thoroughbreds. PROCEDURE Horses were randomly assigned to 2 groups. Horses in the training group were trained for 16 weeks, and control horses were kept on pasture without training. Samples were obtained by use of a needle-biopsy technique from the middle gluteus muscle of each horse before and after the training period. Composition and oxidative enzyme (succinic dehydrogenase [SDHI) activity of each fiber type were determined by use of quantitative histochemical staining procedures. Whole-muscle activity of SDH and glycolytic enzyme (phosphofructokinase) as well as myosin heavy-chain isoforms were analyzed biochemically and electrophoretically, respectively.RESULTS:
The SDH activity of type-I and -IIA fibers increased during growth, whereas whole-muscle activity was unchanged. Percentage of type-IIX/B muscle fibers decreased during training, whereas that of myosin heavy-chain IIa increased. The SDH activity of each fiber type as well as whole-muscle SDH activity increased during training. An especially noticeable increase in SDH activity was found in type-IIX/B fibers. CONCLUSIONS AND CLINICAL RELEVANCE Changes in muscle fibers of adolescent Thoroughbreds are caused by training and not by growth. The most noticeable change was for the SDH activity of type-IIX/B fibers. These changes in the gluteus medius muscle of adolescent Thoroughbreds were considered to be appropriate adaptations to running middle distances at high speeds.
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Base de dados:
MEDLINE
Assunto principal:
Condicionamento Físico Animal
/
Adaptação Fisiológica
/
Músculo Esquelético
/
Cavalos
Limite:
Animals
Idioma:
En
Ano de publicação:
2002
Tipo de documento:
Article