To Co-Design TendAdhere: A theory and evidence based guide for Physiotherapists to help people with Achilles tendinopathy adhere to NHS Exercise Treatment

Background Achilles tendinopathy (AT) is a common musculoskeletal condition with an incidence comparable to knee osteoarthritis. The pathophysiology of AT is not fully understood but results in tendon pain both at rest and on movement. NHS treatment is progressive calf-muscle strengthening exercises for at least 12 weeks which is highly effective when people adhere to the treatment. Unfortunately, adherence within the NHS population is low resulting in 23-60% of people with AT experiencing pain and poor quality of life a decade after diagnosis and treatment. Poor outcomes are most notable in underserved populations including people with multiple health conditions, socioeconomic disadvantage and low physical activity levels. Neither physiotherapists nor people with AT are able to identify and prioritise an individual's main barriers to adherence. This makes generating tailored solutions to address an individual's non-adherence impossible. Aim To co-design an intervention to guide physiotherapists and patients to select theory, evidence-based behaviour change techniques tailored to individual need to support adherence with NHS exercise treatment for AT. Methods Working with my culturally and socially diverse PPIE team of six people with AT and other co-morbidities, I will deliver the following research programme. Workstream 1 Months 5-12: I will interview up to 30 people with AT to explore the barriers and enablers (determinants) of non-adherence through the lens of the Theoretical Domains Framework (TDF). I will use abductive thematic analysis with my PPI team: (i) to identify determinants (ii) map determinants to their relevant TDF domains and (iii) prioritise determinants for addressing. Workstream 2 Months 12-18: I will convene three rounds of co-design workshops with 12-20 people with AT selected from workstream 1 interviewees. Working with my PPI team, we will guide participants to help us prepare prototypes of the behaviour change techniques that they pick to address the prioritised determinants from workstream 1. The combination of a list of the determinants of people adhering to AT exercise treatment and related behaviour change techniques for physiotherapists to deliver will be called TendAdhere. Workstream 3 Months 19-36: I will invite 12 physiotherapists to test TendAdhere with patient actors. They will then participate in a focus group discussion to establish what is necessary to help them fidelitously deliver TendAdhere. The focus group topic guide will be structured around the Consolidated Framework for Implementation Research which will also guide selecting components to support implementation. Impact Through patient and community engagement, TendAdhere aims to create an intervention tailored for diverse patient populations to achieve the necessary adherence to AT exercise treatment that will resolve the condition. By the end of the PhD, I will have prepared a fellowship application to feasibility test TendAdhere followed by a definitive trial to provide the evidence necessary for national implementation. Dissemination My dissemination strategy will be guided by people with AT, physiotherapists, community well-being staff and commissioners. It will include preparing articles for academic, professional and patient-focused publications to share evidence to support future practice change. I will also share messages from the research via conferences, social media, webinars, and workshops.