Investigating the response of the equine respiratory muscles to training

Abstract

The aim of this study was to develop methods for the assessment of the equine respiratory muscles, measuring their size, strength, and function, to determine the response to both conventional exercise training and inspiratory muscle training. Repeatable techniques for ultrasound measurement of respiratory muscle size were developed, with a range of muscles examined using previously defined protocols or novel approaches. Bespoke equipment and training protocols were developed to facilitate the application of inspiratory muscle training in horses. In addition, a novel inspiratory muscle strength test was created to provide an index of inspiratory muscle strength.

Evaluation of a cohort of Thoroughbred racehorses in training for competition in National Hunt races, showed that there was a significant increase in the index of inspiratory muscle strength in response to both conventional exercise training and high-load inspiratory muscle training. In addition, there was an increase in the size of respiratory and locomotor muscles in response to conventional exercise training, with a further increase in diaphragm size in response to inspiratory muscle training. Preliminary analysis suggests an association between diaphragm size and race performance. Overall, the application of inspiratory muscle training was well tolerated.

Objective methods for the assessment of upper airway function were developed including a grading scheme and automated analysis using deep machine learning. Inspiratory muscle training was performed in horses diagnosed with dynamic upper airway collapse, with lower severity of vocal fold collapse, palatal instability, and intermittent dorsal displacement of the soft palate recorded following inspiratory muscle training.

The results of these investigations show that there is a measurable response of the equine respiratory muscles to both conventional exercise training and inspiratory muscle training, with an increase in the muscle size, inspiratory muscle strength, and improved function of the upper airway, providing the foundations upon which further studies can be undertaken.

Date of Award	25 Jan 2022
Original language	English
Awarding Institution	University of Bristol
Supervisor	Kate J Allen (Supervisor), Melanie J Hezzell (Supervisor) & Becky R Whay (Supervisor)