Promoting Routine Exercise in Frail Nursing Home Residents through Nudge-Based Strategies: Protocol for an Exploratory Sequential Mixed-Methods Study

Background Exercise is among the best evidence-based practices for mitigating frailty. In nursing homes, their uptake and sustainability largely depend on care staff, who serve as the primary organizers and frontline leaders of exercise. However, high workloads and staff shortages can limit the effectiveness and scalability of traditional exercise-change approaches. Nudge theory offers a complementary, low-burden strategy by subtly redesigning the choice environment to promote desired behaviors without requiring substantial additional cognitive effort or resources. Therefore, this study aims to develop and evaluate a nudge-based intervention guided by the Fogg Behaviour Model, the Care staff-Administered Routine nudge Exercise (CARE) program, to embed and sustain routine exercise for frail older adults in nursing homes, thereby slowing frailty progression and improving health-related outcomes. Methods An exploratory sequential mixed-methods design will be used. Semi-structured interviews with care staff will be conducted to explore their perceptions and experiences of delivering supervised exercise to older adults, as well as perceived barriers to implementation. Based on these findings, a literature review of nudge-based behaviour changes strategies and the expert working group, the finalized CARE program will be designed. The program will be evaluated via a quasi-experimental hybrid type II effectiveness-implementation design. The effectiveness and implementation outcomes will be measured via the RE-AIM framework. Discussion This study shifts the perspective from directing changing older adults’ behavior to nudging care staff in nursing homes. Guided by the Fogg Behavior Model, the CARE approach targets three leverage points—enhancing ability, strengthening motivation, and optimizing contextual prompts—to facilitate the sustained implementation of exercise in nursing homes. If supported by our findings, this work will provide a theoretical basis for developing innovative frailty management strategies among nursing homes. Trial registration: This study was registered at Chinese Clinical Trial Registry on the 28 April 2025 with the identifier ChiCTR2500101681.