Note: [] School of Physical and Health Education, Queen's University,
Kingston, Ontario K7L 3N6, Canada. Fax: +1 613 545 2009
Abstract: The purpose of this study was to develop and validate a one camera
analysis strategy to correct for the effects of perspective error due to out of
plane rotation on the calculation of L4/L5 moment and compression and shear
forces. A mathematical model was derived around the geometric relationship of a
T-Bar shaped device and the measured camera to object plane distance. This
geometric relationship was used to reorient a rotated subject back into the
perpendicular film plane before calculation of joint moments and forces.
Systematic errors (rotational perspective errors, forward/backward and
side/side distances of subject from camera) and random errors (digitization
error, anthropometrics, lifting techniques) were determined with maximum errors
of 10.5%, within \pm20^\circ out of plane
rotations. Results generally supported incorporation of a correctional device
to extend the use of two-dimensional analysis strategies in industrial
settings.
