Autonomic nervous system responses as performance indicators among volleyball players.

Complex motor skills require planning and programming before execution. The autonomic nervous system (ANS) is thought to transcribe these central operations at the peripheral level: a motor act is thought to be simultaneously programmed by central and autonomic nervous structures. The aim of this study was to verify that autonomic responses reflect the quality of central motor programming leading to successful or failed performance when subjects are required to perform a complex motor skill. The specificity of the ANS response has already been demonstrated through direct recording from sympathetic fibres. It has also been demonstrated through several mental tasks and closed motor skills such as shooting: ANS responses have been shown to be capable of distinguishing success from failure. The aim of this experiment was to test whether ANS responses are capable of distinguishing two levels of achievement during the performance of a skill involving uncertainty (open skill). The subjects had to intercept a ball on a volleyball court, using the forearm receive and pass technique, in order to pass it on to a moving human target. The results were displayed in terms of accuracy: accurate passes were successful and inaccurate passes missed the target. Six autonomic variables were recorded simultaneously during the task: skin resistance and potential, skin blood flow and temperature, instantaneous heart rate and respiratory frequency. Results showed that autonomic variables were capable of distinguishing success from failure in 22 subjects out of 24. This made it possible to build up autonomic patterns characterising subjects' performances, and to confirm that autonomic functioning may reveal information processing in the central nervous system. Thus, the study of autonomic responses may constitute an inferential model of central nervous system functioning. Such a method could be used as an index for the control of mental preparation.