Back pain and diseases of the spine and pelvis are significant problems in all types of performance horses, potentially causing poor performance, lost training days and wastage. As a result, back pain represents a considerable economic and welfare issue for the equine performance industries. Evaluation of back problems in performance horses is an important part of physiotherapy and veterinary practice. Yet back pain syndromes are insidious and difficult to diagnose due to the variability of presenting signs ranging from overt lameness or pain on palpation of the back to subtle gait alterations or even behavioural changes. Complicating matters further, multiple problems often coexist, particularly lameness and back pain Research to date has been led by the veterinary profession with a focus on pathoanatomical problems underlying back pain. However, advances in human back pain have been led by physiotherapy research. Physiotherapy research has focussed on the neuromotor control model and the associated dysfunction, especially of the epaxial or deep back muscles that occurs as a result of back pain from different forms of pathology. Therefore, our overall aim was to increase the knowledge of back pain in horses by using this novel approach. Specifically; how pathology of the back itself or other parts of the musculoskeletal system is reflected in the epaxial muscles and to determine the relationship between atrophy or dysfunction of these muscles and pain and/or poor athletic performance.