3D measurement of cervical and thoracic postural dynamism in sitting : a pilot study

[摘要] ENGLISH ABSTRACT: The aim of this study was to improve the measurement of postural dynamism in the sitting position using a three-dimensional (3D) motion analysis system. The primary objective was to describe pilot data for postural dynamism of the cervical and thoracic spines while working at a desktop computer. The secondary objective was to refine the process of posture measurement and analysis by decreasing data processing time. Certain factors in 3D motion analysis can lead to an increase in gaps in data collected during trial capture, which in turn will lead to a longer time of data processing. In the first phase of this study, a number of such factors were identified and altered. A series of pilot studies was performed to test the improvement of data processing time when altering these factors. In the first two pilot studies, camera and tripod positionings were explored and refined, workstation layout and anatomical landmark marker placement were investigated, and optimal capture frequency was established. In both these pilot studies, outcomes were established by means of trial and error by experimenting with a variety of different options for the different outcomes. In the third pilot study, computer software which provides computer tasks for the participant during primary trial capture was tested. Two independent computer users performed all the activities as per software, after which they were required to give oral feedback and suggestions on improvement in terms of user friendliness. The objective of the fourth and final pilot study was to include all of the outcomes from the preceeding pilot studies and attempt a trial run of the actual data collection process. A study participant with no affiliation to the research project was used and a complete trial run was performed after which the measurement process was deemed feasible. In the primary study, 18 student volunteers completed a sequence of computer tasks, including keyboard, mouse and reading activities. Prior to data capture, full range of motion of the thoracic and cervical spines were measured in three dimensions for every participant. Data capture took place for the full duration of performance of all computer activities. Outcome parameters for postural dynamism included true range of motion (degrees), proportional range of motion (percentage) and motion frequency (movement per minute) in all three planes of motion of the cervical and thoracic spines. Typing tasks were associated with biggest movement ranges and motion frequencies. Mouse activity was associated with the most stationary posture, exhibiting the least frequent movement as well as the smallest ranges of motion.The results from this study allow us to better understand the dynamic nature of posture, as well as postural dynamism associated with different computer tasks. This study provides a baseline for future research of 3D motion analysis of the sitting posture. It also marks the need for further research regarding ergonomics, use and potential alternatives in the computer workstation and input devices.

[发布机构] Stellenbosch University