An accelerometer-based single-arm dynamic stability test for the assessment of the sensorimotor control of the shoulder

This is the authors' abstract. We don't add key points for this paper.

The study aimed at designing and validating a variation of the Single-Arm Dynamic Stability test as performed in Open Kinetic Chain for assessing the shoulder's sensorimotor control with the subject lying supine while holding a dumbbell still in one hand with the extended arm. The dumbbell's sway, monitored via a triaxial accelerometer, was modelled as an inverted pendulum pivoted at shoulder level. Twenty college students performed bilateral tests for 30 s using loads of 15 %, 25 %, and 35 % of a reference load determined as the mass measured by a scale placed under the hands during a quadruped position. The test was repeated 30 min and 24 h later. Time- and frequency-domain stabilometric parameters were computed using both the entire 30 s test duration and the first 20 s. ICC analysis revealed that the test as performed at 15 % of the reference load exhibited the highest intra- and inter-day reliability for both sides and durations, while reliability decreased at higher loads. Specifically, Jerk and swayArea exhibited good-to-excellent intra-day reliability (ICC = 0.866-0.947) and moderate-to-good inter-day reliability (ICC = 0.707-0.766), with 30 s test duration. All other stabilometric parameters showed moderate or moderate-to-good reliability (ICC > 0.5). The test provides a reliable, accessible, and ecologically valid assessment of shoulder sensorimotor control, with potential applications in clinical settings.