Effectiveness of Smart Insole System on Otago Training: A Pilot Randomized Crossover Study

[Introduction] The Otago Exercise Programme (OEP) is an evidence-based fall prevention program for older adults, yet its effectiveness in home settings is limited by poor adherence and unsupervised, incorrect execution. Real-time digital monitoring presents a viable solution to bridge this gap. This pilot study aims to evaluate the feasibility and preliminary efficacy of a smart insole system (iBalanx), which was designed to provide real-time auditory feedback during OEP training. 

[Methods] A pilot randomized crossover study was conducted with six community-dwelling older adults (aged≥65). Participants completed OEP sessions under two conditions in a randomized order: Feedback-ON (FB-ON) and Feedback-OFF (FB-OFF). Objective outcomes included: 1) joint range of motion (ROM) and movement consistency (Coefficient of Variation, CV) for resistive tasks, and 2) mediolateral stability (MTH Ratio CV) and task duration for static balance tasks. Subjective usability was assessed via the System Usability Scale (SUS).

[Results] During resistive tasks, the FB-ON condition consistently resulted in greater ROM and improved movement consistency, indicating enhanced exercise intensity and motor control. Specifically, Calf Raises showed the most significant ROM improvement (34.27° to 43.58°, p=0.028) and stability gain (CV decreasing from 12.23% to 9.06%, p=0.028). In static balance tasks, real-time feedback contributed to reduced mediolateral pressure variability (MTH Ratio CV) and significantly extended the duration participants maintained their balance in both Tandem Stance and One-Leg Stand (p=0.028). Subjectively, the system achieved a mean System Usability Scale (SUS) score of 60.42±14.54, indicating marginal acceptability with high scores in feedback comprehensibility.

[Conclusion] The iBalanx system demonstrated promising feasibility and preliminary efficacy for supervising home-based OEP. By enhancing movement intensity, improving stability, and ensuring exercise duration as prescribed, it holds promise as a practical tool to support high-quality, long-term adherence to OEP in community settings.

Keywords: fall prevention, older adults, wearable sensors, real-time feedback, Otago exercise programme

Affiliation: 1. Department of Biomedical Engineering, The Hong Kong Polytechnic University; 2. Research Institute for Smart Ageing, The Hong Kong Polytechnic University.

Acknowledgement: This work was supported by the Health and Medical Research Fund, the Health Bureau, The Government of the Hong Kong Special Administrative Region- Research Fellowship Scheme (Reference number: 09230037; HHB/H/41/69).