Flexibility of equine bioenergetics and muscle plasticity in response to different types of training: An integrative approach, questioning existing paradigms.
Authors: de Meeûs d'Argenteuil Constance, Boshuizen Berit, Oosterlinck Maarten, van de Winkel Don, De Spiegelaere Ward, de Bruijn Cornelis Marinus, Goethals Klara, Vanderperren Katrien, Delesalle Cathérine John Ghislaine
Journal: PloS one
Summary
# Editorial Summary Conventional equine training science has centred on glycogen and fatty acid metabolism, but de Meeûs d'Argenteuil and colleagues employed untargeted metabolomics alongside traditional muscle analysis to reveal a far more nuanced bioenergetic picture in Friesian horses undergoing either aquatic or dry treadmill training over eight weeks. Aquatraining proved superior for building hindquarter muscle diameter (peak effect at four weeks), whilst treadmill work induced markedly different adaptations across muscle groups: the pectoralis shifted toward oxidative metabolism with increased type I fibres, whereas the vastus lateralis paradoxically reduced in diameter whilst upregulating glycolytic capacity and expanding its fast-twitch profile. Beyond the expected shifts in fatty acid oxidation and tricarboxylic acid cycle activity, the study identified substantial changes in branched-chain and aromatic amino acid metabolism, along with microbiome-derived metabolites (xenobiotics such as p-cresol glucuronide) that may feed the TCA cycle downstream of acetyl-CoA—likely being oxidised in type IIA fibres, the horse's predominant fibre type. For practitioners, these findings challenge conventional training paradigms and suggest that amino acid nutrition and gut metabolite production warrant considerably greater attention in training programmes, whilst the differential muscle responses to aquatic versus land-based work provide evidence-based rationale for periodising these modalities according to specific adaptation goals.
Read the full abstract on PubMed
Practical Takeaways
- •Aquatraining produces superior hindquarter muscle development compared to treadmill work alone—consider incorporating water training for horses requiring rapid muscle hypertrophy
- •Different muscles adapt distinctly to the same training stimulus; expect forehand muscle development and oxidative adaptation from treadmill work, while hindquarters develop fast-twitch capacity
- •Current equine nutrition focuses on glycogen and fat, but amino acid metabolism appears critical for performance—review protein quality and amino acid balance in training diets
Key Findings
- •Aquatraining increased hindquarter muscle diameter more effectively than dry treadmill training, with maximum effect at 4 weeks
- •Dry treadmill training induced oxidative metabolism in pectoralis muscle with increased type I fibers and β-oxidation of long-chain fatty acids
- •Vastus lateralis showed fast-twitch fiber expansion with increased glycolytic and pentose phosphate pathway activity in response to treadmill training
- •Branched-chain and aromatic amino acids are underrecognized fuels for equine exercise, oxidized primarily in type IIA fibers