Measurement Of Sit-stand And Stand-sit Transitions Using A Tri-axial Accelerometer On The Lower Back

Alan Godfrey, Gillian Barry, John Mathers, Lynn Rochester

Research output: Contribution to conferencePoster

Abstract

INTRODUCTION: The study of ambulatory human motion with accelerometer -based activity monitors has increased in many areas of biomedical research. These research areas include the monitoring of both older and younger adults. Reduction in sensor size coupled with more powerful data mining techniques have enabled the use of single sensor devices for longitudinal monitoring but sensor location and algorithm complexity play a key role in deriving a more complete activity summary. PURPOSE: The study aimed to investigate the feasibility of a discrete accelerometer-based sensor located on the lower back (L5) in determining sit-to-stand (SiSt) and stand-to-sit (StSi) postural transitions based upon a previous algorithm [1]. METHODS: Participants wore the AX3 (Axivity, York, UK) tri-axial accelerometer-based sensor on the lumbar vertebrae (L5). The device was attached by means of double sided tape and Hypafix. Sampling rate for the AX3 was set at 100 Hertz (Hz). Participants were initially told to stand still for 10 seconds to calibrate the accelerometers prior to testing. Participants were then asked to perform 3 SiSt and StSi transitions from 2 chairs (chair with/without arm rests, height = 43cm) at the notification of a researcher. Upon completion data were downloaded and analysed using MATLAB. CONCLUSION: Postural transitions can be accurately detected for older and younger adults with an accelerometer-based sensor located on L5. Previously the VESPA algorithm solely utilised vertical velocity estimates to differentiate between SiSt and StSi transitions. To improve the detection rates presented here, future work will incorporate vertical displacement values calculated from the vertical velocity. In addition, longitudinal (7 day) community based data will be assessed in comparison with a commercial activity monitor (activPAL™) to assess long term suitability and accuracy.
Original languageEnglish
Publication statusPublished - 17 Jun 2014
EventICAMPAM 2013 - 3rd International Conference on Ambulatory Monitoring of Physical Activity and Movement - Amherst, MA
Duration: 17 Jun 2014 → …

Conference

ConferenceICAMPAM 2013 - 3rd International Conference on Ambulatory Monitoring of Physical Activity and Movement
Period17/06/14 → …

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