Upright static pelvic posture as rotations and translations in 3-dimensional from three 2-dimensional digital images: validation of a computerized analysis.

PURPOSE: The aim of this study was to determine the accuracy in measuring the pelvic orientations of a phantom model using the PosturePrint method. METHODS: In the Université du Québec à Trois-Rivières biomechanics laboratory, Trois-Rivières, Quebec, Canada, a mannequin was fixed on a rotating platf...

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Bibliographic Details
Published in:Journal of Manipulative & Physiological Therapeutics Vol. 31; no. 2; pp. 137 - 146
Main Authors: Harrison DE, Janik TJ, Cailliet R, Harrison DD, Normand MC, Perron DL, Oakley PA
Format: pictorial research tables/charts Journal Article
Published: Elsevier B.V. Feb2008
Online Access:View this record in EBSCOhost
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Summary:PURPOSE: The aim of this study was to determine the accuracy in measuring the pelvic orientations of a phantom model using the PosturePrint method. METHODS: In the Université du Québec à Trois-Rivières biomechanics laboratory, Trois-Rivières, Quebec, Canada, a mannequin was fixed on a rotating platform. For a set of 3 photographs (left lateral, anterior to posterior, right lateral) of each position, the mannequin pelvis was placed in 68 different postures on a stand, 61 cm from a wall, in front of a digital camera. The camera was at 83.8 cm in height and at 3.35 m from a calibrated wall grid. Mannequin postures were in 5 degrees of freedom: lateral translation (Tx), lateral flexion (Rz), axial rotation (Ry), flexion-extension (Rx), and anterior-posterior translation (Tz). Average errors were the differences of the positioned postures to the PosturePrint computed values. RESULTS: Mean and SD of computational errors for rotation displacements were Rx = 0.5 degrees +/- 0.8 degrees , Ry = 1.3 degrees +/- 0.8 degrees , and Rz = 0.5 degrees +/- 0.3 degrees , and for translation, Tz = 1.2 +/- 0.6 mm and Tx = 0.9 +/- 0.5 mm. CONCLUSIONS: The PosturePrint system allowed for accurate postural measurement of rotations and translations of a mannequin pelvis. The next step in evaluation of this product would be a reliability study on human subjects.