The effect of combined action observation therapy and eccentric exercises in the treatment of mid-portion Achilles tendinopathy: study protocol for a feasibility pilot randomised controlled trial

BACKGROUND: Mid-portion Achilles tendinopathy (AT) is a common overuse injury which can be difficult to successfully rehabilitate. Whilst peripherally directed treatment approaches that strengthen the Achilles tendon complex can be efficacious for some individuals, others will continue to experience long-standing pain and functional deficits. Expanding our rehabilitation approach beyond the tendon mechanical properties to include techniques which target the central neurophysiological changes which can occur in chronic injuries, including mid-portion AT, may improve our rehabilitation outcomes. Action observation therapy (AOT) is one such technique which targets central changes and can enhance motor learning. To our knowledge, there is currently no available information on the combined effect of AOT and eccentric exercises in the rehabilitation of mid-portion AT, nor understanding of the feasibility of conducting randomised controlled trials that investigate this combined centrally and peripherally directed treatment approach. This protocol outlines the design of a remotely conducted parallel-group randomised controlled trial comparing the efficacy of combined AOT and eccentric loading exercises versus eccentric loading exercises alone for mid-portion AT. METHODS: Participants recruited throughout Ireland with mid-portion AT will be randomly assigned to one of the following groups: (i) The AOT group will observe videos of the eccentric exercises prior to the physical performance of the eccentric exercises. (ii) The control group will observe videos of landscapes prior to the performance of the eccentric exercises. This is a 12-week daily intervention as per the Alfredson loading protocol and outcome measures will be assessed at baseline, week 6 and week 12. Primary feasibility outcomes will include data on numbers of eligible participants, recruitment and retention rates, along with exercise compliance and acceptability of treatment. The primary clinical outcome measure will be the Victorian Institution Symptom Assessment-Achilles Questionnaire (VISA-A) assessing disability. Secondary clinical outcomes will address the remaining core domains as outlined by the International Scientific Tendinopathy Symposium consensus (ICON group) including pain, participation, functional, physical function capacity, quality of life and psychological factors. Widespread bodily pain and centralised pain features and patient satisfaction levels will also be evaluated. DISCUSSION: This study will provide scientific direction for future randomised controlled trials exploring the effect of AOT and eccentric exercises in the treatment of mid-portion AT on pain, centralised pain features, motor and non-motor functions, quality of life and patient satisfaction levels. The feasibility of the conducting a study remotely from participant screening to final follow-up assessment will also be provided. TRIAL REGISTRATION: ISRCTN58161116