Trajectories and predictors of adherence to the StandingTall digital exercise program
Abstract
Background: Long-term adherence to exercise and digital health interventions is critical but remains a major challenge, particularly among older people. While balance exercise is effective in preventing falls, little is known about how older people engage with such programs over time, and what drives sustained adherence.
Methods: We analysed adherence data from 511 community-living older people who participated in a home-based digital balance exercise program for 52 weeks. Participants were prescribed two hours of exercise per week, with progressive weekly targets and adherence automatically recorded by the app. Using group-based trajectory modelling, we identified distinct patterns of adherence and examined predictors of these patterns based on cognitive, physical, demographic and psychological characteristics.
Results: Eight behavioural trajectories emerged (i.e., overachievers, consistent adherers, fluctuating adherers, intermittent adherers, late attrition, steady decliners, early attrition, non-adherers), ranging from consistent high adherence to early attrition. Average adherence across the cohort was moderate (56%) of the prescribed dose over 52 weeks. Two objective measures of behavioural capability (i.e., executive function and standing balance) predicted adherence trajectories. Poorer executive function was associated with “boom-and-bust” patterns, while poorer balance was linked to more sustained adherence, suggesting a greater perceived need for training. No demographic or general health factors predicted adherence.
Conclusions: Adherence to digital exercise is a dynamic process shaped primarily by cognitive capacity and balance ability rather than age or health status. Framed within the COM-B model, our findings demonstrate that behavioural capability predicts long-term adherence and reveal a critical early window for targeted support. Despite regular follow-up calls, adherence declined most steeply in the first 10-15 weeks, highlighting a gap in behaviourally focused strategies. This study establishes a new behavioural framework for precision engagement in digital health, with implications for the design of adaptive, personalised interventions that support older people to age well at home.
Comments
This is a really helpful study.
This is so interesting - and great to see these aspects of behaviour change being considered - even though an average adherence rate of 56% over a whole year seems excellent for a falls prevention program. (A quick google search states that 'Up to 80% of people who start an exercise program or join a gym stop showing up consistently within their first 90 days.")
I always joke that no-one does what the physiotherapist tells them to do... often the people who then complain that physiotherapy does not work. Getting our clients to adhere to any program is always difficult, particularly after the initial enthusiasm has worn off and when there is no-one there to pester them anymore. We know that education is very helpful in improving adherence. Probing into these other areas of the COM-B could also be very useful. What was used to assess cognitive function?
As an aside, executive function is often messy in people with ADHD, (under-diagnosed in these older age groups). I wonder if all the techniques used to maintain engagement in younger people with ADHD would help here?
Thank you, Anna Stackpool
Reply to Anna Stackpool - This is a really helpful study.
Dear Anna,
Thank you for your kind words. To answer your question: executive function was assessed using the Trail Making Test Part B (TMT-B), which captures the ability to shift between tasks and sustain self-directed effort, exactly the kind of capacity needed to maintain an independent exercise routine over a year.
Your ADHD observation is interesting. The "boom-and-bust" pattern we identified could possibly be related to what we see in ADHD - high initial engagement followed by a steep decline - and you're right that it is significantly under-diagnosed in older adults. We have embedded strategies such as automated reminders, immediate feedback and short sessions to reduce reliance on internal motivation. Whether routine screening for executive function difficulties could help personalise support from the outset is something we are currently exploring.
Kind regards,
Kim Delbaere