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Skeletal muscle characteristics in young trained and untrained Standardbred trotters
Author(s) -
RONÉUS MERIKE,
ESSÉNGUSTAVSSON BIRGITTA,
LINDHOLM A.,
PERSSON S. G. B.
Publication year - 1992
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.2042-3306.1992.tb02838.x
Subject(s) - medicine , citrate synthase , horse , zoology , biology , paleontology , biochemistry , enzyme
Summary Muscle biopsies were taken from the middle gluteal muscle of 28 Standardbred trotters, 3–4 years of age. The 13 horses in Group T were trained consistently from 18 months of age, whereas the 15 horses in Group UT were not exposed to any systematic training before 3 years of age. Group T horses had a lower percentage of Type IIB fibres (31%) than did Group UT horses (39%). Citrate synthase (CS) activity, representing oxidative capacity, was higher in Group T (72 mmol kg −1 min −1 ) than in Group UT (47 mmol kg −1 min −1 ). Biopsies were taken from 4 horses in each group when they were foals and then annually until 3–4 years of age. Results from this study indicate that regular training of Standardbreds from 18 months of age resulted in increased CS activity and a decrease in the percentage of Type IIB fibres. This study shows that training, not growth, is the main factor that induces a high oxidative capacity and a high Type IIA/IIB fibre ratio in muscle of Standardbred trotters.