Use of 'wearables' to assess the up-on-the-toes test

Abstract

The mechanical output at the ankle provides key contribution to everyday activities, particularly step/stair ascent and descent. Age-related decline in ankle functioning can lead to an increased risk of falls on steps and stairs. The rising up-on-the-toes (UTT) 30-second test (UTT-30) is used in the clinical assessment of ankle muscle strength/function and endurance; the main outcome being how many repetitive UTT movements are completed. This preliminary study describes how inertial measurement units (IMUs) can be used to assess the UTT-30. Twenty adults (26.2 ± 7.7 years) performed a UTT-30 at a comfortable speed, with IMUs attached to the dorsal aspect of each foot. Use of IMUs' angular velocity signal to detect the peak plantarflexion angular velocity (p-fAngVel_peak) associated with each repeated UTT movement indicated the number of UTT movements attempted by each participant. Any UTT movements that were performed with a p-fAngVel_peak 2SD below the mean were deemed to have not been completed over a sufficiently 'full' range. Findings highlight that use of IMUs can provide valid assessment of the UTT 30-second test. Their use detected the same number of attempted UTT movements as that observed by a researcher (average difference, -0.1 CI, -0.2 - 0.1), and on average 97.6 ± 3.1% of these movements were deemed to have been completed 'fully'. We discuss the limitations of our approach for identifying the movements not completed fully, and how assessing the consistency in the magnitude of the repeated p-fAngVel_peak could be undertaken and what this would indicate about UTT-30 performance.

Keywords: Ankle function; Inertial measurement units; Plantar-flexion strength; Up-on-the-toes.