Maximum Tolerated Dose of Walking for Community-Dwelling People Recovering From Hip Fracture: A Dose-Response Trial

Objective: To determine how much moderate-intensity physical activity, in the form of walking, could be prescribed for people living in the community after hip fracture in terms of safety, tolerability, and feasibility.

Design: Phase I dose-response design.

Setting: Public community rehabilitation centers.

Participants: Community-dwelling adults (N=21; 16 women; mean age, 75±9y) who were cognitively alert, attending community rehabilitation after hip fracture (mean days postfracture, 110±47d), able to walk with or without a gait aid, and for whom it was safe to participate in physical activity.

Interventions: Individually supervised doses of moderate-intensity walking completed in 1 week in addition to their usual levels of physical activity. Three participants were required to complete a dose of walking before dose escalation for the next cohort of 3 participants. Dose escalation ceased when >1 participant in a cohort had an adverse event or was unable to tolerate the dose or if the maximum dose of 150min/wk was achieved.

Main outcome measures: Maximum tolerated dose of walking per week (in minutes), adverse events, mobility, and walking confidence.

Results: The maximum tolerated dose of walking for adults after hip fracture before significant discomfort was experienced (eg, breathlessness, pain, and fatigue) by any participant was 100min/wk. No adverse events occurred, but participants began to be unable to tolerate higher doses beyond 100min/wk.

Conclusions: This provides preliminary evidence that community-dwelling older adults recovering from hip fracture can complete a sufficient amount of moderate-intensity physical activity to maintain and improve their health.