Date Published: February 26, 2019
Publisher: Public Library of Science
Author(s): Ryota Takamido, Keiko Yokoyama, Yuji Yamamoto, Bryan C. Daniels.
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.
We can perform a task-oriented behavior corresponding to the changes of environmental demands. A typical example is an interpersonal and/or team sports activity. In martial arts, experts perform attacking and defending maneuvers based on the not-to-lose strategy, adjusting optimal interpersonal distance [1–4]. In team sports, experts can perceive the movements of other teammates and coordinate with them [5, 6]. These complex movements are performed under various task constraints, such as rules or using tools. Players, especially in interpersonal and/or team sports, are required to undertake quick decision-making and provide an accurate response. Accordingly, temporal constraints have become more important.
The data for two high school batters were eliminated based on the results of the application of the local outlier factor method. A total of 120 batters (39 high school, 36 college, and 45 league batters) were analyzed overall.
This study aimed at clarifying the relationship between the task constraints of different competition categories and the stepping movement of fast-pitch softball batters in Japan. Table 2 summarizes these results. First, we investigated how temporal constraints differ in each competition category (Hypothesis 1). The results demonstrated significant differences between the league and the other two categories. These temporal and tool constraints affected their stepping movements in terms of both initiation time and step duration (hypotheses 2 and 3). The cluster analysis using two dependent variables comprising the initiation time and the step duration revealed three types of stepping movement, that is, LS, EL, and ES types in fast-pitch softball (Hypothesis 4). The players in each category were classified into a particular type of stepping movement corresponding to the temporal and tool constraints in each category (Hypothesis 5). However, high school players performed using the EL and LS types; college players were classified into only the LS type; and league players were classified into all three types of stepping movement.
This study aimed to clarify the relationship between the task constraints and the preparatory movement of fast-pitch softball batters in the three Japanese competition categories. The players in each category with their respective temporal and tool constraints showed a particular type of stepping movement as a preparatory movement corresponding to each task constraint. However, some players in every category showed late initiation and short step duration of the stepping movements even if under high temporal constraints. They chose their preparatory movements as a not-to-lose strategy under various task constraints, which suggests that they solve tasks by exploiting the redundancy in solutions in the task space under task constraints.