School- and home-based hybrid exercise intervention to prevent summer fitness loss in children: protocol for a feasibility study of the keep moving in a structured summer programme.

Abstract

Schools are key settings to intervene for the purpose of health promotion in children. However, the effectiveness of school-based interventions remains limited, potentially related to the obesogenic behaviours observed during holidays as posited by the structured days hypothesis. This study aims to evaluate the feasibility, process evaluation and preliminary efficacy of the keep moving in a structured summer (KEMOSS) intervention among Chinese children. The KEMOSS intervention is an 8-week hybrid programme comprising two digitally supported home-based phases (weeks 1-2 and 7-8) and a structured school-based phase (weeks 3-6). The school-based phase will be a full-day scheduled programme that replicates the routine of regular school days, with a coach-led structured physical activity lesson and a free-play lesson embedded in the morning and afternoon, respectively. During the home-based phases, participants will be encouraged to complete prescribed exercises independently with support from mHealth reminders and instructional materials and to achieve a minimum of 10 000 steps per day. Feasibility, process evaluation and preliminary efficacy outcomes will be assessed using a mixed-methods approach. Quantitative data will be analysed using SPSS, while qualitative data from interviews and focus groups will be analysed thematically using NVivo. Ethical approval has been obtained from the Ningbo University Ethics Committee (TY2026028). Findings will inform the refinement of the intervention and the design of a future definitive trial. Results will be disseminated through peer-reviewed publications and conference presentations. ChiCTR2600126738.