Abstract
The perspective error in two-dimensional motion analysis based on film and/or video images was theoretically quantified, and the practical effects of the error on the accuracy in two-dimensional kinematic variables were investigated using the data of sprint running. The equations proposed in the present study may be useful for estimating the amount of perspective error and determining appropriate camera distance in two-dimensional motion analysis. In practical analysis of human movement, the error affects translational and rotational kinematics of limb segments. If the optical axis of the camera is perpendicular to the calibration plane and the intersection of the axis and plane can be detected, the effects of perspective error on translational kinematics for the limb segments can be reduced to a certain extent.
