Currently submitted to: JMIR mHealth and uHealth
Date Submitted: Jul 26, 2026
Open Peer Review Period: Jul 29, 2026 - Sep 23, 2026
(currently open for review)
Warning: This is an author submission that is not peer-reviewed or edited. Preprints - unless they show as "accepted" - should not be relied on to guide clinical practice or health-related behavior and should not be reported in news media as established information.
App–Based Individualized Postural Control Training Versus Home Exercise and Control for Individuals with Chronic Ankle Instability: Randomized Controlled Trial
ABSTRACT
Background:
Chronic ankle instability (CAI) is characterized by high recurrence rates and persistent sensorimotor deficits. While smartphone applications offer accessible alternatives for postural control training, their potential to drive automated, individualized rehabilitation algorithms and to support real-world behavioral adherence remains underexplored.
Objective:
This study aimed to evaluate the clinical effectiveness of a smartphone app-based individualized postural control training system for CAI, to strictly assess the longitudinal responsiveness of consumer-grade smartphone sensors, and to explore behavioral adherence compared with human-supported care.
Methods:
A single-blind, three-arm randomized controlled trial was conducted with a 6-week intervention and a 4-week follow-up. Forty-six participants with CAI were randomly allocated (1:1:1) to an App-based training group, a therapist-prescribed home exercise group, or an education-only control group. Primary outcomes included static and dynamic postural control. Secondary outcomes were self-reported function (FAOS, FAAM-Sports) and training adherence. Data were analyzed using linear mixed models following the intention-to-treat principle.
Results:
No significant group-by-time interactions were observed for any static or dynamic postural control metrics, nor for self-reported functional outcomes (all P > .05). Significant improvements over time were widespread across all three groups. The smartphone accelerometer failed to detect significant longitudinal changes over time, limiting the algorithm's capacity for objective progression. Despite high perceived usability ratings, objectively logged adherence in the App group (62%) was highly variable and lower than the self-reported adherence in the Home exercise group (74%).
Conclusions:
Automating assessment and exercise prescription via a smartphone app did not outperform human-supported home exercise or structured education with weekly contact. Favorable usability does not guarantee sustained behavioral engagement. Future mobile health development must rigorously validate sensor sensitivity for longitudinal responsiveness and actively integrate social accountability design to address digital attrition. Clinical Trial: ClinicalTrials.gov NCT03849547.
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