Review of arm motion analyses

Interest in arm movements has increased tremendously in recent years. This interest has been motivated by different goals: the desire for a more scien tific approach to replacement or support of the joints of the upper limb, t he need for input to biomechanical computer models, and the clinical intere st in comparing normal movements with pathological movements. The availabil ity of commercial marker-tracking systems has facilitated achieving these g oals. However, the complex nature of arm movements and the lack of standard ized movements raises many challenges. In comparison with gait analysis, fe w arm motion analyses have been conducted. The purpose of this review is to aid researchers and clinicians interested in conducting an arm motion stud y in choosing the appropriate methodology. This is accomplished both by des cribing the methods used in past investigations and by highlighting importa nt findings. Due to the variety of research goals, there is sometimes more than one appropriate method and the choice is left to the reader. Neverthel ess, since it is extremely desirable to record and express the data in a st andardized way, standardization proposals are described. This review, which focuses on methodology rather than results, addresses the following topics : motivations and tasks studied, tracking methods, the shoulder complex, jo int centres and relation axes, marker positions, coordinate system definiti ons, terminology and rotations, accuracy, and presentation methods.