Development of a cost effective three-dimensional posture analysis tool: validity and reliability
Date
2013Author
Brink, Yolandi
Louw, Quinette
Grimmer, Karen
Schreve, Kristiaan
van der Westhuizen, Gareth
Jordaan, Esme
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Show full item recordAbstract
BACKGROUND: The lack of clear understanding of the association between sitting posture and adolescent
musculoskeletal pain, might reflect invalid and/or unreliable posture measurement instruments. The psychometric
properties of any new measurement instrument should be demonstrated prior to use for research or clinical
purposes. This paper describes psychometric testing of a new three-dimensional (3D), portable, non-invasive posture
analysis tool (3D-PAT), from sequential studies using a mannequin and high school students.
METHODS: The first study compared the 3D-(X-, Y- and Z-) coordinates of reflective markers placed on a mannequin
using the 3D-PAT, and the Vicon motion analysis system. This study also tested the reliability of taking repeated
measures of the 3D-coordinates of the reflective markers. The second study determined the concurrent validity and
test-retest reliability of the 3D-PAT measurements of nine sitting postural angles of high school students undertaking a
standard computing task. In both studies, concordance correlation coefficients and Intraclass correlation coefficients
described test-retest reliability, whilst Pearson product moment correlation coefficients and Bland-Altman plots
demonstrated concurrent validity.
RESULTS: The 3D-PAT provides reliable and valid 3D measurements of five of the nine postural angles i.e. head
flexion, neck flexion, cranio-cervical angle, trunk flexion and head lateral bending in adolescents undertaking a
standard task.
CONCLUSIONS: The 3D-PAT is appropriate for research and clinical settings to measure five upper quadrant postural
angles in three dimensions. As a measurement instrument it can provide further understanding of the relationship
between sitting posture, changes to sitting posture and adolescent musculoskeletal pain.