著者

松尾 知之 平野 裕一 川村 卓

出版者

一般社団法人 日本体育学会

雑誌

体育学研究 (ISSN:04846710)

巻号頁・発行日

vol.58, no.1, pp.195-210, 2013 (Released:2013-06-08)

参考文献数

18

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Expert players and/or expert coaches have a large stock of experiential knowledge, including knowledge of movement-related causality. We attempted to extract experiential knowledge of movement-related causality in baseball pitching from expert players and coaches with sufficient creditability. Verbal data collected in a previous study (Matsuo et al. 2010) using semi-structured interviews with four former professional baseball pitchers and seven expert baseball coaches were used for this study. The data had been categorized on the basis of a wide variety of coaching points. A matrix of co-occurrence based on the verbal data was used to calculate the strength of association between pairs of categories. In the process of the calculation, we employed the matrix calculation utilized in the Dematel method to count indirect associations. The distances among categories, calculated on the basis of co-occurrence probability, were used to assess the creditability of the verbal data. The categories were mapped into three-dimensional space using the least squares method, based on the distances. The associations of categories were extracted as highly trustworthy when the root mean squared error between the original distances and the mapped distances was below 10%. Among the extracted associations, the direction of causality was added to the associations that expressed the causality explicitly among the verbal data. The major selected causalities were as follows:1)  Moving forward before placing weight on the pivot foot sufficiently opens the trunk earlier and leads to insufficient weight being placed on the stride foot.2)  An inadequate take-back action, especially excessive horizontal abduction and elbow extension, limits the flexible arm movement around throwing-side ear and leads to lower shoulder abduction. In addition, it makes the trunk open earlier.3)  Excessive lead elbow extension during the stride phase makes the trunk open earlier. How the lead-arm is pulled towards the trunk also affects trunk rotation.4)  Bending the neck at any point leads to inadequate trunk rotation.