Effects of a submaximal treadmill training programme on histochemical properties, enzyme activities and glycogen utilisation of skeletal muscle in the horse.

The research article outlines a study that explored the effects of a seven-week submaximal treadmill training programme on the composition of skeletal muscle in horses, studying parameters such as muscle fibre types, oxidative capacity, capillary numbers, and glycogen utilisation.

Introduction and Methodology

• In this research, the scientists utilised four Standardbred geldings (male horses) to study the effects that submaximal treadmill training has on the composition of skeletal muscle.
• This involved carrying out muscle biopsies on the left middle gluteal muscle of the horses, which was done before the training program began. The purpose of these biopsies was to determine the muscle fibre types, oxidative capacity, and capillary numbers.
• The research also measured the concentrations of certain enzymes, including citrate synthase, 3-hydroxyacyl-CoA dehydrogenase (HAD), and lactate dehydrogenase. In addition, the total muscle glycogen, a form of sugar that provides energy for the muscles, was also measured.
• This same series of tests and measurements were repeated after one, three, five, and seven weeks of undergoing the training programme.

Findings

• The results of the study found that no significant changes occurred in muscle fibre types or capillary numbers due to the training.
• However, the oxidative capacity of the Type IIB fibres saw an increase after being subject to seven weeks of training.
• Concentrations of citrate synthase and HAD also increased after seven weeks, while lactate dehydrogenase saw a decrease.
• Apart from the muscle composition, the glycogen utilisation during a standardised submaximal exercise test was also tracked. The measurements showed a consistent decrease in the rate of glycogen utilisation across the period of training. By the end of seven weeks, this rate was 36% lower than the rate before the training started.

Conclusion

• In conclusion, the seven-week submaximal treadmill training program has shown to impact the properties and activities in the skeletal muscle of horses, with adjustments in select enzyme concentrations, oxidative capacity, and a pronounced reduction in the rate of glycogen utilisation.
• These findings provide a deeper understanding of how training programmes can be tailored to optimise performance in horses, particularly in the domain of endurance and stamina.