Development and evaluation of the ARM algorithm: A novel approach to quantify musculoskeletal disorder risk factors in manual wheelchair users in the real world

Abstract

This study aimed to develop and evaluate the ARM (arm repetitive movement) algorithm using inertial measurement unit (IMU) data to assess repetitive arm motion in manual wheelchair (MWC) users in real-world settings. The algorithm was tested on community data from four MWC users with spinal cord injury and compared with video-based analysis. Additionally, the algorithm was applied to in-home and free-living environment data from two and sixteen MWC users, respectively, to assess its utility in quantifying differences across activities of daily living and between dominant and non-dominant arms. The ARM algorithm accurately estimated active and resting times (>98%) in the community and confirmed asymmetries between dominant and non-dominant arm usage in in-home and free-living environment data. Analysis of free-living environment data revealed that the total resting bout time was significantly longer (P = 0.049) and total active bout time was significantly shorter (P = 0.011) for the non-dominant arm. Analysis of active bouts longer than 10 seconds showed higher total time (P = 0.015), average duration (P = 0.026), and number of movement cycles per bout (P = 0.020) for the dominant side. These findings support the feasibility of using the IMU-based ARM algorithm to assess repetitive arm motion and monitor shoulder disorder risk factors in MWC users during daily activities.

Fig 1. Definition of active and resting bouts based on humeral elevation data.

(A): Illustrates the definition of a movement cycle, including an Elevation event, a Lowering event, and Idle time. (B): Illustrates an interval between two consecutive movement cycles. (C): Depicts active bouts (wheelchair propulsion) and resting bouts (intervals greater than 7 sec) in red and green horizontal bars, respectively.

Fig 2. Box plots for average duration of resting bouts.

(a), average duration, average number of movement cycles per active bout, average median humeral elevation angle, and average peak humeral elevation angle for all active bouts (b-e) and for only active bouts that were longer than 10 seconds (f-i), and statistical results for comparing the parameters between dominant (Dom) and non-dominant (Non-Dom) arms. Data collection from 16 MWC users with SCI during free-living.