Kinematic and force data collection in biomechanics by means of sonic emitters--I: Kinematic data collection methodology.

In this paper, first, the principles of sonic digitizing are presented. Next, a description of quantitative determination of the relative motion between two body segments by utilization of sonic emitters is provided. A new kinematic data collection methodology and data analysis is proposed to check continuously the accuracy of the data collected by means of the sonic emitters. The first part of the paper is terminated by establishment of an accuracy criteria and selection of the most accurate data set and associated error analysis. Quantitative results based upon the kinematic data collection methodology of Part I were obtained for the forced kinematic motion of the human shoulder complex and are presented in Part II.