Contribution of exercise intensity and duration to training-linked myosin transitions in thoroughbreds.
Abstract: The influence of relevant exercise parameters such as intensity and duration of exercise on the muscular response to training has not been reported in Thoroughbreds. This knowledge may be of great value in practice. Objective: To define the relative contribution of the intensity and duration of exercise on the myosin heavy chain (MHC) response to training in Thoroughbred racehorses. Methods: Six 2-3-year-old Thoroughbreds, following a randomised 6 x 6 latin square design, performed 6 consecutive conditioning programmes of varying lactate-guided intensities and durations. Each programme lasted 22 days and consisted of 11 exercise sessions once a day, every second day on a 6% inclined treadmill followed by a 10 day resting period between consecutive programmes. Gluteus muscle biopsies (depth, 2 and 6 cm) were taken before, and after, each programme and electrophoretically analysed for MHCs. Results: Overall, training increased the fraction of MHC IIA (mean +/- s.d., 41.1 +/- 3.5% to 43.4 +/- 4.42% P<0.001) and decreased that of MHC IIX isoform (from 50.2 +/- 4.4% to 47.4 +/- 5.6% P<0.001). Exercise intensity fixed effects on fast MHCs were highly significant (P<0.01), whereas exercise duration only had a marginal effect (P<0.1) on the IIA:IIX MHC ratio. On a per-individual basis, training impact on fast MHCs was only significant (P<0.05) in horses exercised for the longest duration at both intensities. Conclusions: The short-term training-induced up-regulation of MHC IIA and down-regulation of MHC IIX in Thoroughbreds are more dependent on intensity than duration of exercise. However, protocols with exercises of moderate intensity and long duration can induce MHC changes similar to those promoted by programmes with exercises of higher intensities. Conclusions: Exercises for up to 25 min/day at velocities eliciting a blood lactate concentration between 2.5 and 4 mmol/l every second day for 3 weeks improve stamina in Thoroughbreds.
Publication Date: 2007-04-04 PubMed ID: 17402438DOI: 10.1111/j.2042-3306.2006.tb05559.xGoogle Scholar: Lookup
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- Journal Article
- Randomized Controlled Trial
- Research Support
- Non-U.S. Gov't
Summary
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The research aims to identify the relative contributions of exercise intensity and duration to the changes in myosin heavy chain (MHC), a muscle fiber type, in Thoroughbred racehorses during their training. The study found that exercise intensity had a more significant effect on these changes than exercise duration.
Research Methodology
- The researchers used six 2-3-year-old Thoroughbred horses in a 6 x 6 latin square designed study.
- The horses underwent six consecutive training programs of varying intensity and duration, based on lactate measurements. Each program lasted 22 days with exercise sessions conducted once a day for every second day.
- These physical exercise sessions were performed on a 6% inclined treadmill. After each program, the horses were given a 10-day resting period
- The gluteus muscle of the horses was biopsied before and after each exercise program, then analyzed electrophoretically for myosin heavy chain (MHC).
Key Findings
- Training increased the fraction of MHC IIA from 41.1% to 43.4%, and decreased MHC IIX isoform from 50.2% to 47.4%.
- Exercise intensity had a highly significant effect on fast MHCs, whereas exercise duration had a minimal effect on the IIA-to-IIX MHC ratio.
- On a per-individual basis, the impact of training on fast MHCs was only significant in horses that underwent exercise for the longest duration at both intensities.
Conclusions
- Exercise intensity had a more substantial effect on training-induced up-regulation of MHC IIA and down-regulation of MHC IIX in Thoroughbreds than the duration of the exercises.
- However, protocols with both moderate intensity and long duration led to changes in MHC similar to those caused by programs with higher intensity exercises.
- Exercises lasting up to 25 minutes a day, at velocities that cause a blood lactate concentration between 2.5 and 4 mmol/l every other day for three weeks, improved the stamina of Thoroughbreds.
This finding might be useful to trainers and horse owners to optimize horse training for improved performance and health.
Cite This Article
APA
Rivero JL, Ruz A, Marti-Korfft S, Lindner A.
(2007).
Contribution of exercise intensity and duration to training-linked myosin transitions in thoroughbreds.
Equine Vet J Suppl(36), 311-315.
https://doi.org/10.1111/j.2042-3306.2006.tb05559.x Publication
Researcher Affiliations
- Laboratory of Muscular Biopathology, Department of Comparative Anatomy and Pathological Anatomy, Faculty of Veterinary Sciences, University of Cordoba, Campus Rabanales, Edificio de Sanidad Animal, Cordoba, Spain.
MeSH Terms
- Animals
- Cross-Over Studies
- Exercise Test / veterinary
- Female
- Horses / physiology
- Male
- Muscle, Skeletal / chemistry
- Muscle, Skeletal / metabolism
- Myosin Heavy Chains / analysis
- Myosin Heavy Chains / metabolism
- Oxygen Consumption / physiology
- Physical Conditioning, Animal / physiology
- Protein Isoforms
- Time Factors
Citations
This article has been cited 3 times.- de Meeûs d'Argenteuil C, Boshuizen B, Oosterlinck M, van de Winkel D, De Spiegelaere W, de Bruijn CM, Goethals K, Vanderperren K, Delesalle CJG. Flexibility of equine bioenergetics and muscle plasticity in response to different types of training: An integrative approach, questioning existing paradigms. PLoS One 2021;16(4):e0249922.
- Bryan K, McGivney BA, Farries G, McGettigan PA, McGivney CL, Gough KF, MacHugh DE, Katz LM, Hill EW. Equine skeletal muscle adaptations to exercise and training: evidence of differential regulation of autophagosomal and mitochondrial components. BMC Genomics 2017 Aug 9;18(1):595.
- McGivney BA, McGettigan PA, Browne JA, Evans AC, Fonseca RG, Loftus BJ, Lohan A, MacHugh DE, Murphy BA, Katz LM, Hill EW. Characterization of the equine skeletal muscle transcriptome identifies novel functional responses to exercise training. BMC Genomics 2010 Jun 23;11:398.
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