Validity of load rate estimation using accelerometers during physical activity on an anti-gravity treadmill

• Published in: Journal of rehabilitation and assistive technologies engineering Vol. 8; p. 2055668320929551
• Main Authors: Nazirizadeh, Susan, Stokes, Maria, Arden, Nigel K, Forrester, Alexander IJ
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.01.2021; Sage Publications Ltd
• Subjects: Accelerometers; Exercise; Smartphones; Smartwatches; Special Collection: Wearable Technologies for Active Living and Rehabilitation; Wearable computers; smartwatch; bootstrapping; smartphone; linear mixed model; load rate monitoring; Physical activity monitoring
• ISSN: 2055-6683; 2055-6683
• DOI: 10.1177/2055668320929551

Introduction A simple tool to estimate loading on the lower limb joints outside a laboratory may be useful for people who suffer from degenerative joint disease. Here, the accelerometers on board of wearables (smartwatch, smartphone) were used to estimate the load rate on the lower limbs and were compared to data from a treadmill force plate. The aim was to assess the validity of wearables to estimate load rate transmitted through the joints. Methods Twelve healthy participants (female n = 4, male n = 8; aged 26 ± 3 years; height: 175 ± 15 cm; body mass: 71 ± 9 kg) carried wearables, while performing locomotive activities on an anti-gravity treadmill with an integrated force plate. Acceleration data from the wearables and force plate data were used to estimate the load rate. The treadmill enabled 7680 data points to be obtained, allowing a good estimate of uncertainty to be examined. A linear regression model and cross-validation with 1000 bootstrap resamples were used to assess the validation. Results Significant correlation was found between load rate from the force plate and wearables (smartphone: R 2 = 0.71 ; smartwatch: R 2 = 0.67 ). Conclusion Wearables’ accelerometers can estimate load rate, and the good correlation with force plate data supports their use as a surrogate when assessing lower limb joint loading in field environments.