Acquiring coordination in self-paced, extrinsic timing tasks: A constraints-led perspective

In this paper the volleyball serve is used as an exemplar of self-paced ext rinsic timing tasks and a constraints-led approach to the acquisition of co ordination ir advocated From this perspective, a neo-Darwinian approach to the study of biological systems is invoked to understand how interacting co nstraints influence the emergence of coordination within the movement syste m. The implications for the organisation of practice in volleyball, particu larly with respect to task decomposition, are discussed. To this end, recen t proposals have suggested that examining how coordination is achieved in s killed performers can be used to structure practice for learners. Our analy sis of the volleyball serve showed that a highly consistent placement of th e ball in the left-right and forward-backward dimensions was not essential for successful serving. Whilst performers tended to compensate for variance s in the x and y directions, they stabilised the vertical position of the b all at it's zenith and contact, despite a range of initial conditions and b all flight trajectories. On the basis of these results, it seems that pract ice of the serve should emphasise the acquisition of an invariant peak heig ht of ball toss rather than consistency in the left-right and forward-backw ard directions. Further when ball-placement was practised by skilled athlet es, with and without striking greater amplitude and variability in ball zen ith was observed in the former condition. The intrepretation is that decoup ling informational and physical constraints in practice is less conductive to successful performance. Moreover the evidence suggests that the strategy of studying skilled athletes can aid understanding of how to decompose tas ks during spout skill acquisition.