Finding the right balance with participation in exercise and sport for individuals with multiple sclerosis: protocol for a pre and post intervention feasibility study. INTRODUCTION:  Individuals with minimal disability from multiple sclerosis (MS) requested advice on finding the right balance, between too much and too little exercise, when participating in their choice of sport or exercise. To optimise exercise participation during the early stages of the disease, a flexible exercise participation programme (FEPP) has been developed. The FEPP is novel because it provides guidance and support for individuals with MS to participate and progress in their preferred sport or exercise. The primary objective was to assess the feasibility of the FEPP. The secondary objective was to assess the feasibility of a larger trial to demonstrate the efficacy of the FEPP. METHODS AND ANALYSIS:  A stage I feasibility study of the FEPP, using a single group preintervention/post-intervention design, will be conducted with 16 participants with minimal disability from MS (Expanded Disability Status Scale level of 0-3.5). The 12-week FEPP will guide participants to independently participate in their preferred sport or exercise at a location of their choice. Exercise progression will be guided by individual energy levels and a weekly telephone coaching session with a physiotherapist. Participation in exercise or sport will be recorded in parallel with assessment of disease biomarkers (plasma cytokines interleukin (IL)-2, IL-4, IL-6, IL-10, interferon (IFN)-γ and tumour necrosis factor (TNF)), subjective vitality and high-level mobility. Acceptability of the FEPP will be assessed using a sequential explanatory mixed methods design where the findings of a participant survey will inform the interview guide for a series of focus groups.Feasibility of a larger trial will be assessed via process, resources, management and scientific metrics. Progression to a larger trial will depend on the achievement of specified minimum success criteria. ETHICS AND DISSEMINATION:  Ethical approval has been obtained for this study from the James Cook University Human Research Ethics Committee (H7956). Dissemination of findings is planned via peer-reviewed journals, conference presentations and media releases. The protocol date was 21 December 2019, V.1. TRIAL REGISTRATION NUMBER:  The trial is registered with Australian New Zealand Clinical Trials Registry (ANZCTR), ACTRN12620000076976.