Background: Slip, trips, and falls are a common cause of injury in older adults; limiting physical activity participation and mobility task performance. These injuries may result in preclinical mobility limitation (PCML), a period in which individuals report modifications but not difficulty in mobility tasks. Individuals with PCML are at risk of functional decline which can be prevented with exercise. High-intensity functional strength training (HIFST) involves short intervals of hard interspersed with easy exercise that may be a time efficient strategy to improve functioning for older adults experiencing PCML. Objective: This protocol outlines the rationale, methods, and planned analyses for a pilot randomized controlled trial and qualitative description (QD) to investigate the feasibility, preliminary effects, and acceptability of a home-based 12-week HIFST intervention for community-dwelling older adults (≥ 55 years) with PCML who have had an injury from a slip, trip, or fall. Methods: Twenty-four participants (target) will be randomized into a 12-week home-based HIFST or lower extremity stretching intervention. Feasibility will be determined using criteria for adherence, recruitment, retention, and safety and results will be presented using descriptive statistics. Preliminary effects on physical functioning, cognitive functioning, enjoyment, and harms will be assessed and presented as mean between-group differences with 95% confidence intervals. HIFST participants will be recruited for follow-up interviews using QD methodology to investigate the acceptability of the intervention. The results of this pilot trial will provide essential information for future research regarding the process, resources, and scientific merit of conducting home-based high-intensity exercise in a post-injury older adult population. Trial Registration: NCT05266911 Keywords: pilot study; mobility limitation; high-intensity exercise; older adults; tele-rehabilitation

The authors have declared no competing interest.

NCT05266911

This study did not received any funding.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

Hamilton Integrated Research Ethics Board gave ethical approval for this work (project #13879).

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