Use of wearable technology for performance assessment: a validation study

Abstract

The prevalence of osteoarthritis is increasing globally but current compliance with rehabilitation remains poor. This study explores whether wearable sensors can be used to provide objective measures of performance with a view to using them as motivators to aid compliance to osteoarthritis rehabilitation. More specifically, the use of a novel attachable wearable sensor integrated into clothing and inertial measurement units located in two different positions, at the waist and thigh pocket, was investigated. Fourteen healthy volunteers were asked to complete exercises adapted from a knee osteoarthritis rehabilitation programme whilst wearing the three sensors including five times sit-to-stand test, treadmill walking at slow, preferred and fast speeds. The performances of the three sensors were validated against a motion capture system and an instrumented treadmill. The systems showed a high correlation (r(2) > 0.7) and agreement (mean difference range: -0.02-0.03 m, 0.005-0.68 s) with gold standards. The novel attachable wearable sensor was able to monitor exercise tasks as well as the inertial measurement units (ICC > 0.95). Results also suggested that a functional placement (e.g., situated in a pocket) is a valid position for performance monitoring. This study shows the potential use of wearable technologies for assessing subject performance during exercise and suggests functional solutions to enhance acceptance.

Keywords: Acceleration; Exercise; Osteoarthritis; Performance; Rehabilitation; Wearable sensor.

Fig. 1

Participant set-up during the test. Systems positioning is visible as well as markers attachment on the right greater trochanter (RGT) and right posterior iliac spine (RPSIS). Although two attachable sensors are present in the photo, only one was connected via cables to sensing node and used for the tests.

Fig. 2

Correlation and Bland Altman plot of agreement for the waist IMU (□), thigh IMU (◯) and AWS (^) against Vicon reference for FTSST duration. Horizontal lines represent the mean difference and the upper and lower limit of agreements (dotted line).

Fig. 3

Correlation and Bland Altman plot of agreement for the waist IMU (□), thigh IMU (◯) and AWS (^) against estimated parameters by the treadmill for stride time and length at slow speed. Horizontal lines represent the mean difference and the upper and lower limit of agreements (dotted line).

Fig. 4

Correlation and Bland Altman plot of agreement for the waist IMU (□), thigh IMU (◯) and AWS (^) against estimated parameters by the treadmill for stride time and length at self-selected speed. Horizontal lines represent the mean difference and the upper and lower limit of agreements (dotted line).

Fig. 5

Correlation and Bland Altman plot of agreement for the waist IMU (□), thigh IMU (◯) and AWS (^) against estimated parameters by the treadmill for stride time and length at fast speed. Horizontal lines represent the mean difference and the upper and lower limit of agreements (dotted line).