Movement biomechanics goes upwards: from the leg to the arm

The analysis of lower limb movements has been well established in biomechan ics research and clinical applications for a long time. For these studies, powerful and very advanced tools have been developed to measure movement pa rameters and reaction forces. The main focus of interest aims towards gait movements while the understanding of the basic concepts is supported by num erous models. Definitions of physiological ranges and detection of patholog ical changes in movements open an increasingly valuable clinical field of a pplication. If, however, the primary function of the upper extremities as h ighly variable and adaptive organ for manipulating tasks is the subject of interest, the situation becomes considerably more complex. The nature of fr ee arm movements is completely different from being restricted, repeatable or cyclic as compared to gait. Therefore, the transfer of the knowledge and experience gained in lower extremity movement analysis to the analysis of upper extremities turns out to be difficult. A proposal for how to proceed in measurements, e.g. where to place the markers and how to calculate movem ents and angles of segments involved, will be discussed which results in th e description of the joint movements of wrist, elbow and shoulder joint. Th e definition of the motion is a specific step in upper extremity motion ana lysis which is important in terms of repeatability and significance of the results. An example of assessing movement disorders in children with plexus lesion will illustrate the implications and the potential of upper extremi ty movement analysis in clinical applications. (C) 2000 Elsevier Science Lt d. All rights reserved.