Using relative motion plots to measure changes in intra-limb and inter-limb coordination.

Methods for determining the degree of similarity between relative motion plots are examined and computational methods outlined. Hypothetical examples are provided to simply illustrate the function of selected indices of pattern shape, size, and orientation. Methods of using a composite of these measures to assess asymmetry, abnormality, or refinements in motor function are discussed. Statistical procedures for determining the reliability of assessments of change in relative motions are presented. A modification to Freeman's (1961) pattern-recognition method is suggested as a more parsimonious application to angle-angle data derived in human movement research.