ABSTRACT
Kinematic information obtained from quantitative analysis can also be used, in combination with body segment parameters (see section C) to calculate center of mass kinematics, segmental energy levels and power (see section D), and joint moments and forces (see sections B and C). Quantitative analysis generally requires the video camera(s) to be stationary and located in a specific position(s), and the images subsequently to be stored in and displayed on a computer. Each image is then digitized to provide horizontal (x) and vertical (y) coordinates of selected points on the body, usually segment end points. These coordinates are then scaled (2D) or reconstructed (3D) to provide real-life coordinates, and smoothed to reduce errors that are inevitably incurred during their collection (see section F). They are also often combined with temporal information to obtain velocities and accelerations. The following text details how video cameras should be used quantitatively to analyze motion that essentially occurs in a single plane (e.g., cycling, running) and multiple planes (e.g., cricket bowling, shot put), as well as digitizing and scaling/reconstruction of coordinates. Smoothing of coordinates will be dealt with in section F3.
