The application of co-ordination dynamics to the analysis of discrete movements using table-tennis as a paradigm skill

The purpose of this experiment was to explore the application of co-ordinat ion dynamics to the analysis of discrete rather than cyclical movements. Su bjects, standing in a fixed position, were required to return table-tennis balls delivered to different spatial locations in the direction of a fixed target. This was achieved in condition I by systematically scaling, from le ft to right and vice versa, the 'spatial location' of the ball-identified a s a control parameter. In condition 2, the control condition, the spatial l ocation was varied randomly over the same range. The changes between regime s of the stroke co-ordination pattern, defined at two different levels, (1) organisational-forehand or backhand drive, and (2) kinematic-the distance of the bat at ball-bat contact relative to the leading edge of the table, w ere identified as collective variables, the values of which changed spontan eously at the transition points exposed by the control parameter. The switc h between regimes was shown to be dependent upon the direction of scaling, i.e. a hysteresis effect was identified in both conditions. These findings confirm that the conceptual and methodological frameworks of co-ordination dynamics can be applied, appropriately, to the analysis of discrete movemen ts. Moreover, it would seem that control parameter values (spatial location of the ball) do not necessarily have to be scaled in a systematic way in o rder to produce the required effects.