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Doctoral thesis, 1997

Muscle metabolic response to track exercise in Standardbred trotters

Ronéus, Nils


This study was undertaken to investigate if measurement of plasma lactate concentration and certain muscle characteristics following a track test can provide important information about a horse's performance capacity.
In Standardbred trotters, marked individual differences are evident in plasma lactate concentration and muscle metabolic responses to maximal and submaximal work performed on a race-course. A negative correlation was found between plasma lactate concentration to a submaximal test, and the horse's maximal trotting speed over 1600 m, and a more marked anaerobic glycolysis and ATP breakdown during maximal exercise, than had slower horses.
Inverse correlations were found between stance time and both plasma lactate and percentage oftype IIB fibres, indicating that locomotion pattern may be partly dependent on both fibre type composition and metabolic profile in muscle. Neither fibre type composition, enzyme activities, nor plasma lactate or ammonia concentration after a race showed any correlation with performance potential, expressed as individual performance index (DPI).
The results of this study also show that adenine nucleotide breakdown in muscle is of great importance for energy release during racing and that ATP and IMP concentrations can vary markedly among individual fibres after a race. Thus, metabolite determinations in whole muscle must be evaluated with caution as they are no more than mean values for metabolic response in different fibres during racing.
​​​​​​​Tactical driving is important in racing; running against time in a track test or an exercise test on a treadmill is therefore more standardized than racing proper. It is evident that measurement ofplasma lactate and certain muscle characteristics after a standardized track test in 2-year-old Standardbred trotters can provide important information about a horse’s performance capacity. This type of information can be useful for trainers when subjecting a young horse to more individual training. However, further research is required before specific, detailed recommendations can be made regarding optimal training methods.


horse; plasma lactate; muscle; muscle characteristics; track test

Published in

Acta Universitatis Agriculturae Sueciae. Veterinaria
1997, number: 6
ISBN: 91-576-5233-3
Publisher: Swedish University of Agricultural Sciences

    SLU Authors

    • Ronéus, Nils

      • Department of Medicine and Surgery, Swedish University of Agricultural Sciences

    UKÄ Subject classification

    Medical Bioscience

    Permanent link to this page (URI)