Skill in sport : the role of action-effect representations
Five experiments were conducted to examine the role of ball trajectory information in the planning, execution, and evaluation of a complex motor skill as a function of skill. This sensory information source could either be predicted to become either more (Koch et al., 2004) or less (Schmidt, 1975) important as skill is acquired. In Experiments 1,2, and 3 the importance of ball trajectory information in the execution of a soccer kick to a target as a function of skill was examined using visual occlusion (Exp 1 and 2) and perturbation (Exp 3) techniques. Skilled performers were able to maintain accuracy when vision of ball trajectory was occluded, although they were shown to use this information when it was available but perturbed. The accuracy of less-skilled performers decreased when vision of ball trajectory was occluded. Across skill groups, variability in knee-ankle coordination also decreased under these conditions. Although these finding was taken as evidence that across skill levels action effects information is used to execute the action when it is available, only at the lower levels of skill did this information aid outcome attainment. In Experiments 4 and 5 the importance of ball trajectory information in the planning of a soccer kick to a target as a function of skill was examined. Skilled and novice soccer players were instructed to plan the action in terms of the ball's trajectory or in terms of the body movements. There was little evidence that actions are more effectively planned by anticipation of their effects or that the ability to do so is skill-dependent (Koch et al., 2004). However, there was some evidence that a body-related focus was detrimental to performance in comparison to control conditions when feedback was removed (McNevin et al., 2003). Although ball trajectory information does not seem to be critical for task success, there was evidence that it is used to plan and perform actions across skill levels. Skilled performers were shown to be less reliant on this information compared to less skilled.