Baseball Catching Patterns Differ According to Task Constraints

We investigated the effect of task constraints on movement patterns and sought to confirm the finding that the combined movement involved in the transition between catching and throwing emerges through self-organization. We conducted two experiments. In Experiment 1, four participants were required to perform two tasks: catch a launched baseball (catching task) and catch the launched baseball and immediately throw it to a target (catching and throwing task). The balls were launched from five spatial positions, and the participants were instructed to catch the balls with their left hand using a baseball glove. We found that the catching movement differed according to the task and spatial constraints. When the ball was launched close to the body in the catching and throwing task, the shoulder and hip segment angles rotated in the direction of the throw, which resulted in combining the terminal phase of catching with the preparatory phase of throwing. In Experiment 2, two participants were asked to complete the catching and throwing task using the same procedure as in Experiment 1, to investigate the sequence effect. Our findings showed that the spatial position at which the trunk rotation switched direction, that is, hysteresis, differed according to the sequence of positions, suggesting that the combination of two movement patterns, such as catching and throwing, emerged through self-organization.