Accuracy improvement in gait analysis measurements: Kinematic modeling

Postural and motor changes in patients affected by abnormalities of movement are the results of the interactions of nervous system, musculoskeletal system and sensorial system. Gait analysis is a good technique to characterize various gait pathologies, and a high accuracy of the results is necessary in order to describe, in quantitative way, functional limitation related to the pathology. In this paper the model for modeling the kinematics of human body is implemented by considering data acquired from a camera of optoelectronic system capable of measuring three-dimensional coordinates of reflective markers placed in known positions on the patient. Kinematic model is reported for pelvis and accuracy of its trajectories acquired by cameras is also investigated. Moreover, since coordinate system of the other joints (hip, ankle, foot) are relative respect pelvic coordinate system, accuracy in its model can reduce errors in evaluation of essential angles to define human motion.