Blended adapted sailing therapy with telerehabilitation for rare skeletal disorders: protocol for a pilot randomised controlled feasibility trial in Italy (PaS2-EXTEND)

Introduction Rare skeletal disorders (RSDs) cause lifelong functional impairment, chronic pain and reduced quality of life. Evidence-based rehabilitation strategies remain underdeveloped, particularly for adolescents and young adults. We previously demonstrated preliminary feasibility of a 5-day adapted sailing intervention but observed benefit attenuation at 3-month follow-up. This pilot trial evaluates feasibility, acceptability and safety of intensive adapted sailing therapy followed by home-based telerehabilitation maintenance versus telerehabilitation alone. Methods and analysis This is a prospective, randomised, assessor-blinded, parallel two-arm pilot feasibility trial. 24 participants aged 12-30 years with confirmed RSDs will randomise with a 1:1 allocation ratio to: (1) 5-day adapted sailing therapy followed by 3-month telerehabilitation (n=12) or (2) 3-month telerehabilitation alone (n=12). Primary outcomes assess feasibility through recruitment efficiency (>= 80% eligible patients enrolled), intervention adherence (>= 75% sessions completed), participant retention (>= 80% at 6-month follow-up), and safety (zero serious adverse events attributable to interventions). Secondary outcomes include sensor-based motor function (balance, gait, upper extremity mobility via inertial measurement units) and patient-reported outcomes (health-related quality of life, functional capacity, kinesiophobia, pain), measured at baseline, 3-month and 6-month follow-up. Exploratory analyses will estimate preliminary between-group effect sizes. Statistical analysis uses intention-to-treat principles with linear mixed-effects models. Ethics and dissemination The study received approval from the Area Vasta Emilia Centro Ethics Committee (363/2025/Sper/IOR) on 7 July 2025. The study is ongoing, and data collection is expected to be completed by March 2026. Results will be disseminated through peer-reviewed open-access publications, conference presentations, patient organisation partnerships and plain-language summaries.