title: Accuracy and concurrent validity of a sensor-based analysis of sit-to-stand movements in older adults.
abstract: Body-fixed motion sensors have been applied for the assessment of sit-to-stand (STS) performance. However, the accuracy and concurrent validity of sensor-based estimations of the body's center of mass (CoM) motion during STS are unclear. Therefore, this study investigated the accuracy and concurrent validity of sensor-based measures of CoM motion during STS in older adults. Accuracy and concurrent validity were investigated by comparing the sensor-based method to a force plate method. Twenty-seven older adults (20 females, 7 males; age: 72-94 years) performed five STS movements while data were collected with force plates and motion sensors on the hip and chest. Hip maximal acceleration provided an accurate estimation of the center of mass (CoM) maximal acceleration (limits of agreement (LOA) smaller than 5% of the CoM maximal acceleration; estimated and real CoM maximal acceleration did not differ (p=0.823)). Other hip STS measures and the chest STS measures did not provide accurate estimations of CoM motion (LOA ranged from -155.6% to 333.3% of the CoM value; sensor-based measures overestimated CoM motion (range p: <0.001 to 0.01)). However, the hip sensor did not overestimate maximal jerk of the CoM (p=0.679). Moderate to very strong associations were observed between sensor-based estimations and actual CoM motion (range r=0.64-0.94, p<0.001). Hence, sensor-based estimations of CoM motion during STS are possible, but accuracy is limited. The sensor-based method cannot replace laboratory methods for a mechanical analysis of CoM motion during STS but it may be a practical alternative for the clinical assessment of STS performance in older persons.
authors.affiliation: University of Groningen, University Medical Center Groningen, Center for Human Movement Sciences, PO Box 196, 9700 AD Groningen, The Netherlands. Electronic address: rubenregterschot@hotmail.com.
authors.forename: G Ruben H
authors.initials: GR
authors.lastname: Regterschot
authors.affiliation: Philips Research Europe, Personal Health Department, High Tech Campus 34, 5656 AE Eindhoven, The Netherlands. Electronic address: wei.zhang01@philips.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Philips Research Europe, Personal Health Department, High Tech Campus 34, 5656 AE Eindhoven, The Netherlands. Electronic address: heribert.baldus@philips.com.
authors.forename: Heribert
authors.initials: H
authors.lastname: Baldus
authors.affiliation: University of Groningen, University Medical Center Groningen, Department of Orthopaedics, PO Box 30.001, 9700 RB Groningen, The Netherlands. Electronic address: m.stevens@umcg.nl.
authors.forename: Martin
authors.initials: M
authors.lastname: Stevens
authors.affiliation: University of Groningen, University Medical Center Groningen, Center for Human Movement Sciences, PO Box 196, 9700 AD Groningen, The Netherlands; Institute of Movement and Sport Gerontology, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933 Cologne, Germany. Electronic address: zijlstra@dshs-koeln.de.
authors.forename: Wiebren
authors.initials: W
authors.lastname: Zijlstra
mesh_terms: D000054:Acceleration; D061725:Accelerometry / Q000295:instrumentation / Q000379:methods*; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D008297:Male; D009038:Motion; D009068:Movement / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D015203:Reproducibility of Results
keywords: Accelerometry; Aged; Clinical assessment; Kinematics; Sit-to-stand