A statistical investigation of the in vivo biomechanical properties of the human shoulder complex

Utilization of the multi-segmented total-human-body models in the simulation of human response to external forces provides an essential input for the injury prediction criteria as well as subsequent design and development of crash protection systems. The effectiveness of these models to accurately predict live-human response depends heavily on the proper biomechanical description of the major articulating joints. In a research effort to obtain in vivo joint property data, the senior author and his associates have developed a data collection methodology by means of sonic emitters. This paper presents a statistical investigation on the kinematics of and passive resistive properties beyond the maximal voluntary sinus of the human shoulder complex for the male population of ages 18-32. Ten subjects were randomly chosen to form the sample. Furthermore, to the knowledge of the authors this paper, for the first time, deals with the subtle arguments related to the choice of a subject-based local joint axis system or a statistically determined sample mean joint axis system to present the data in the most appropriate fashion. The statistical results are obtained in a compact manner so that the results can be easily incorporated into existing mathematical multi-segmented models of the total human body. Finally, the ultimate overall performance of the data acquisition system and efficacy of the associated data analysis technique are manifested by the good repeatability of the sample means and sample standard deviations from three kinematic test runs made on the same sample.