Assessment of Thigh Angular Velocity by an Activity Monitor to Describe Sit-to-Stand Performance

Abstract

The assessment of sit-to-stand (STS) performance is highly relevant, especially in older persons, but testing STS performance in the laboratory does not necessarily reflect STS performance in daily life. Therefore, the aim was to validate a wearable sensor-based measure to be used under unsupervised daily life conditions. Since thigh orientation from horizontal to vertical is characteristic for STS movement, peak angular velocity (PAV) of the thigh was chosen as the outcome variable. A total of 20 younger and older healthy persons and geriatric patients (mean age: 55.5 ± 20.8 years; 55% women) with a wide range of STS performance were instructed to stand up from a chair at their usual pace. STS performance was measured by an activity monitor, force plates, and an opto-electronic system. The association between PAV measured by the thigh-worn activity monitor and PAV measured by the opto-electronic system (gold standard) was r = 0.74. The association between PAV measured by the thigh-worn activity monitor and peak power measured by force plate and opto-electronic system was r = 0.76. The Intra-Class Coefficient (ICC) of agreement between the 2 trials was ICC(A,1) = 0.76. In this sample of persons with a wide range of physical performance, PAV as measured by a thigh-worn acceleration sensor was a valid and reliable measure of STS performance.

Effect of a Passive Exosuit on Sit-to-Stand Performance in Geriatric Patients Measured by Body-Worn Sensors—A Pilot Study

“…The group of patients was well-selected because they had a low walking speed indicating poor physical performance and, according to the senior physician in charge, had problems getting up from the chair. PAV values in this study including only geriatric patients are reasonable but lower than in our previous proof-of-concept study including young healthy persons, older adults and geriatric patients with a mean PAV of 124.6°/s [ 20 ]. Since we measured thigh PAV in a supervised condition (laboratory), this can explain that PAV values were slightly faster than in the study that measured thigh PAV during daily life in healthy volunteers with a mean PAV of 70.7°/s [ 21 ].…”

“…Angular velocity of the thighs was recorded by gyroscopes at 120 Hz. After lowpass filtering with a 3rd order Butterworth filter with a cut-off frequency of 6 Hz, mean PAV of the right and left thigh was calculated and used as the outcome parameter to describe STS performance [ 20 ]. After all measurements, the usability of the exosuit was assessed with the System Usability Score [ 22 ], a 10-question interview scoring 0 (worst) to 100 (best).…”

“…In contrast, wearable sensors, such as accelerometers and gyroscopes, have the potential to describe the STS transfer quantitatively during daily life [ 19 ]. Here, the peak angular velocity (PAV) of the thigh is a relevant and reliable parameter to describe STS performance in a laboratory [ 20 ] and during daily-life activity monitoring [ 21 ].…”