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Energy metabolism in relation to skeletal muscle fibre properties during treadmill exercise
Author(s) -
VALBERG S.,
ESSÉNGUSTAVSSON BIRGITTA,
LINDHOLM A.,
PERSSON S.
Publication year - 1985
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/j.2042-3306.1985.tb02551.x
Subject(s) - citrate synthase , glycogen , glycolysis , lactate dehydrogenase , anaerobic exercise , oxidative phosphorylation , medicine , skeletal muscle , endocrinology , metabolism , chemistry , energy metabolism , horse , biology , enzyme , biochemistry , physiology , paleontology
Summary The skeletal muscle metabolism of horses with a wide range of cardiocirculatory capacities was studied during a standardised near‐maximal exercise test in relation to muscle fibre composition. Although the same amount of work was performed by all horses the amount of triglycerides and glycogen utilised and lactate accumulated differed widely. Both blood and muscle lactate accumulation were positively related to the amount of glycogen utilised. These factors were in turn positively associated with the percentage of Type IIB fibres and consequently negatively associated with the percentage of Type IIA fibres. The percentage of Type IIB fibres was negatively correlated to the activities of the oxidative enzymes citrate synthase and 3‐hydroxyacyl‐CoA‐dehydrogenase and positively associated with the lactate dehydrogenase activity. The results indicate that the horses with a high proportion of Type IIB fibres had a lower muscle oxidative capacity and were, therefore, for energy production, more dependent upon glycolysis with subsequent lactate accumulation than horses which had a high proportion of Type IIA fibres. The different metabolic properties of the muscle fibre types indicate that the pattern of muscle fibre recruitment could have a significant effect on intramuscular substrate utilisation.