A Digitally Supported Outdoor Physical Activity Intervention for Mildly Frail Older Adults in Hong Kong

Summary

The aging population in Hong Kong is projected to reach 36.6% by 2046, with roughly 16.6% of older adults estimated to be mildly frail-a condition linked to higher risks of falls, hospitalization, and mortality. While physical activity (PA) is a key modifiable determinant of frailty, a major service gap exists for mildly frail older adults, who lack tailored support, resources, and long-term self-management programs. Although Hong Kong features over 440 public open spaces equipped with senior-friendly outdoor exercise facilities (OEFs), older adults often lack awareness and knowledge on how to utilize them safely for aerobic, strength, and balance training. Furthermore, existing PA interventions often overlook social-ecological perspectives and fail to optimize built environment resources or address digital literacy barriers to sustain long-term behavior change.

To bridge these gaps, our team developed and preliminary-tested OUTDOOR-FIT, a complex, theory-driven, socio-ecological mHealth intervention. OUTDOOR-FIT synergizes Hong Kong's built environment (OEFs), social and volunteer support, individual goal-setting, and digital health technology (a contextually tailored mobile Application) to empower mildly frail older adults to self-manage their PA habits. Building upon promising preliminary findings and qualitative feedback from our initial pilot RCT, the intervention has been refined to incorporate neighborhood OEF environmental audits, supervised outdoor experiential practice sessions, and a train-the-trainer volunteer model to support digital literacy and engagement.

The main objective of this study is to evaluate the clinical effectiveness and real-world implementation of the refined OUTDOOR-FIT intervention using a hybrid type 1 effectiveness-implementation design. Primary effectiveness outcomes include physical activity levels, exercise self-efficacy, mental well-being, chronic pain, and social loneliness measured immediately post-intervention, as well as at 3-month and 6-month follow-ups. Guided by the Reach, Effectiveness, Adoption, Implementation, and Maintenance (RE-AIM) framework, secondary implementation outcomes include Reach, Effectiveness, Adoption, Implementation fidelity, and Organizational Maintenance.

This study adopts a mixed-methods design embedded within a two-arm cluster randomized controlled trial (cluster RCT) involving community service units. Mildly frail older adults will be cluster-randomized into either (i) the OUTDOOR-FIT intervention group or (ii) a control group.

Quantitative analysis will be conducted to evaluate the immediate and sustained effectiveness of the intervention across the primary health outcomes. The qualitative component will consist of semi-structured interviews with older adult participants and community stakeholders to evaluate intervention adoption, implementation barriers, and long-term organizational maintenance.

Conditions

• Physical Inactivity Frailty

Interventions

BEHAVIORAL

OUTDOOR-FIT

Participants in the intervention group will undergo four weekly educational workshops (once per week), with 1 hour duration led by exercise specialists (i.e., certified personal trainer, kinesiologist, degree in exercise or health sciences), and support by volunteers and mobile application (app). Two of these workshops will include two sessions of senior-friendly OEFs visits. The rest of the workshops will cover various topics including introduction of the app, risk management for exercising outdoor, exercise appropriate for frailer older adults, selecting appropriate exercise intensity, using OEFs for aerobic, strength and balance training, postural awareness when using OEFs, management of pain during exercise, and exercise modification principles when using OEFs, home exercise alternatives in bad weather situation. During the four weeks of intervention, participants will be encouraged to use OEFs by themselves with the assistance of the app.

BEHAVIORAL

Active Control

Participants in the active control group will engage in four weekly health education workshops, each lasting for 60 minutes and including exercise experiential sessions. The workshops will be led by exercise specialists (i.e., certified personal trainer, kinesiologist, degree in exercise or health sciences). The workshops focus on the benefits of different exercises for older adults, particularly older adults with mild frailty. Participants have opportunities to experience different modified exercise suitable for frail older adults that could be practiced as home. This comparator was chosen as this kind of workshop is common and traditional way in promoting PA for mildly frail older adults in community settings.

Sponsors & Collaborators

• The Hong Kong Polytechnic University

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

SUPPORTIVE_CARE

Masking

SINGLE

Model

PARALLEL

Eligibility

Min Age

60 Years

Max Age

100 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2027-02-01

Primary Completion

2028-04-30

Completion

2029-03-03

Countries

• Hong Kong

Study Locations