Effects of a nine-month endurance training programme on muscle composition in the horse.

This research investigates the effects of a nine-month endurance training program on the muscle composition of horses by analyzing the samples collected periodically from their muscles.

Research Methodology

• The researchers began the study by collating muscle biopsy samples from the middle gluteal muscle of seven horses participating in a nine-month endurance training program.
• These samples were gathered before the start of the training program, and later at increments of three, six, and nine months. A fifth sample was also taken three months post the conclusion of training.
• The investigators conducted a histochemical reaction of serial muscle sections for myosin adenosine triphosphatase post acid or alkaline pre-incubation. This was used to identify muscle fibres as type I, IIA, IIB, or IIC.
• The oxidative capacity of individual fibres was gauged using the reduced nicotinamide dinucleotide tetrazolium reductase stain.
• The team counted the intermyofibrillar capillaries adjoining each fibre post-staining through the alpha-amylase periodic acid Schiff technique.

Biochemical Analyses

• The biochemical investigation included a fluorometric measurement of enzymes such as citrate synthase, 3-hydroxy acyl CoA dehydrogenase, and lactate dehydrogenase, as they are indicators of oxidative, beta oxidative, and glycolytic potential, respectively.

Results

• There was a noted increase in the percentage of type IIB fibres exhibiting high levels of nicotinamide dinucleotide tetrazolium reductase staining after three months of training.
• The increase was consistent throughout the training period and maintained even after the training ceased.
• The team noticed an increase in the number of capillaries adjacent to type IIB fibres post six and nine months of training. However, these capillaries returned to near pre-training numbers three months after the training stopped.
• Citrate synthase and 3-hydroxy acyl CoA dehydrogenase activities also saw an increase after three months of training, continuing to rise throughout the training, with the highest activities recorded after nine months.