A generalized joint motion analysis system using Borland C++ for Windows

Abstract

The University of Manitoba Motion Analysis System (UM$\sp2$AS) has been developed to study upper limb motion. Although upper limb motion is of great interest to clinicians, due to its involvement in many daily activities of living, other motions are also of clinical importance. The current work undertakes the adaptation of the UM$\sp2$AS system to a generalized system that allows the examination of whole body motion. The human body is modeled as 9 rigid-body segments, Head/Neck, Thorax, Pelvis, Thigh, Calf, Foot, Upper Arm, Forearm, and Hand, attached together at 8 Joints, C7-T1, Lumbar Sacral, Hip, Knee, Ankle, Shoulder, Elbow, and Wrist. Effectively, one side of the body is modeled. Each joint is allowed 3 degrees of freedom (DOF) and modeled with a spherical joint model. Translation joint motion is not considered. The software implementing the system was written in Borland C++ for Windows with a standard Windows format. Euler angles, with a z-x-y sequence, are used to find the rotations in the joints. A marker generation program was also developed to generate theoretical marker positions for testing the system. Using these theoretical marker positions, the relative error in calculated Euler Angles ranged from $-$2.5% to 1.1%, mean $-$0.001, standard deviation 0.105.