Table tennis expertise influences dual-task costs in timed and self-initiated tasks

Theories on resource sharing predict that performances will suffer under dual-task conditions. However, increases in skill level should decrease attentional resources needed to perform a task, resulting in a reduction of dual-task costs. The current study investigates whether table tennis experts are better able than novices to keep up their motor and cognitive performances in a dual-task situation. Two different cognitive tasks, 3-back and Counting Backwards in steps of 7, and two different table tennis tasks, returns and serves, were assessed in each possible cognitive-motor task combination in a within-subjects design. While 3-back and returns were timed, Counting Backwards and serves were self-initiated. We assumed that self-initiated tasks increase dual-task costs, since the scheduling of the responses requires attentional resources. As predicted, dual-task costs of novices were considerably higher (35%) than those of experts, who did not show costs (-1%). The predicted increase of costs for self-initiated tasks was only observed in the experts, while novices showed a tendency to reduce their dual-task costs for self-initiated tasks. It is argued that this is due to the psychometric properties of the underlying task, since timed tasks were specified by a fixed number of targets and responses. We conclude that cognitive-motor dual-task costs may be a valuable measure of sporting skill, over and above "pure" motor or cognitive performances.