Effects of training at a walk on conventional and underwater treadmills on fiber properties and metabolic responses of superficial digital flexor and gluteal muscles to high-speed exercise in horses.

The research investigates the impacts of conventional and underwater treadmill training on the fiber properties and metabolic responses of the superficial digital flexor and gluteal muscles in horses. It found minor changes in muscle fiber sizes and no notable effects on metabolic or heart rate responses following either type of training.

Research Methods

• The study enlisted six unconditioned Quarter Horse-type horses. These horses were divided into two training groups and subjected to walk training on either conventional and underwater treadmills.
• The training was carried out five days a week, with each session lasting up to 40 minutes, over a period of eight weeks. The study used a randomized crossover design, allowing a 60-day detraining period between different training types.
• The researchers used a standardized exercise test at high speed (SET) to measure the performance of the horses before and after the training period.
• Muscle biopsy specimens were obtained from horses before and after each SET, so that analyte concentrations and fiber characteristics could be measured.

Results and Findings

• The study confirmed that lactate concentration in the superficial digital flexor and gluteal muscles of the horses increased 2- to 3-fold after the standardized exercise tests (SETs).
• No impact was detected on muscle fiber type composition, type II fiber diameter, muscle analyte concentrations, blood lactate concentration, or heart rate responses due to either type of training.
• The maximum diameters of type I fibers were reduced significantly in the gluteal muscle following conventional treadmill training. They were also reduced in the superficial digital flexor muscle with both types of training, with larger maximum diameters being recorded for horses after underwater treadmill training. The minimum fiber diameters were unaffected.

Conclusions

• High intensity SETs involving near-maximal exertion resulted in an anaerobic response in the superficial digital flexor and gluteal muscles of horses.
• The eight-week period of conventional or underwater treadmill training made little difference in type I muscle fiber sizes, but the study noted no impact on muscle metabolic or heart rate responses due to the SETs post-training.
• For rehabilitation involving the use of underwater treadmills, progressing speed-based training is recommended for horses in order to build up fitness for tasks requiring high speed.