Task constraints and stepping movement of fast-pitch softball hitting

This study aims to clarify the relationship between task constraints and the preparatory movement of fast-pitch softball batters in Japan for three different competition categories, namely high school, college, and league. As task constraints, we focused on the temporal and tool constraints and evaluated preparatory movements using initiation time and step duration of the stepping movement in a striking action. First, we confirmed the temporal constraints in each category and then examined the relationship between the temporal constraints and the stepping movements. The results demonstrated that the temporal constraints affected both initiation time and step duration of the stepping movements. Hierarchical cluster analysis was applied to the two variables. Consequently, the stepping movement of the softball players was classified into three types: "late initiation-short duration" (LS), "early initiation-short duration" (ES), and "early initiation-long duration" (EL) corresponding to the task constraints. Finally, the relationship between the task constraints of each category and the stepping movements was examined. The results revealed that high school players exhibited mostly the LS- or EL-type stepping movement; college players exhibited mostly the EL-type stepping movement; and league players exhibited all types. These results depict that the players in each category with each temporal and tool constraint exhibited particular types of stepping movements as a preparatory movement corresponding to each task constraint, thereby arguing that players use a not-to-lose strategy exploiting the redundancy in solutions under various task constraints.