著者

松倉 啓太 浅井 武

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.277-296, 2013 (Released:2013-06-08)

参考文献数

15

被引用文献数

2

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It is believed that the success of the goalkeeper (GK) in saving difficult shots by diving is a key factor in soccer because it can influence the outcome of the game to a large extent. However, the most appropriate way to exert force during the diving motion according to the course of the shot from either leg is still unclear. Therefore, the purpose of this study was to clarify the fundamental mechanism of a GK's diving motion according to the height and distance of the shot. We performed an experiment in which 11 university GKs participated. They were asked to dive toward balls set at 3 different heights located a short or a long distance from the GK. By examining the GKs' diving motions, we calculated the ground reaction force (GRF), joint angular velocity, and joint torque. The results indicated that the magnitude of the GRF under both legs and the direction of the GRF under the ball-side (BS) leg differed with the ball height. We also found that a higher dive by the GKs corresponded to a larger counter-movement of the contralateral-side (CS) leg and a higher stopping power of the BS leg in order to increase the vertical velocity, and more exertion of extension torques at the hip and foot for takeoff compared to those in lower dives. Furthermore, a lower dive of the GKs corresponded to a larger angular impulse of the BS hip adduction after the BS leg touched the ground. These findings suggest that during the takeoff part of the diving motion of a GK, depending on the ball height, the CS leg controls the magnitude of power and the BS leg controls both the magnitude and the direction of power in order for the GK to dive directly towards the ball.

著者

松倉 啓太 浅井 武

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.54, no.2, pp.317-326, 2009-12-10 (Released:2010-02-13)

参考文献数

14

被引用文献数

2

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The present study investigated the area covered by soccer goalkeepers during diving motions (reaching area). Goalkeepers were asked to dive towards the ball in accordance with a directional indicator that presented random electronic displays. To examine the characteristics of goalkeepers' diving motion toward each position of the ball, the time needed to reach the ball (reaching time) was measured, as well as the velocity and trajectory of the diving motion. Comparison of the reaching time for each ball height (upper, medium, and low) when each goalkeeper dived for only a short distance revealed statistically significant differences in attempts to stop the ball, the times increasing in the order medium, upper, low height. When a goalkeeper dived longer distances, there was a significant difference in the reaching time, which increased in the order medium, low, and upper height. No significant differences in reaching time were observed between the left and right sides for the same distances and heights. These results suggest that for short distances, more time is needed for relatively lower heights, whereas for longer distances, more time is needed to reach balls at relatively high levels. In terms of the velocity of the diving motion, when the center point between the shoulders was measured with the ball at longer distances, there was a trend for an acceleration phase to start 0.3 s after the directional indicator had been shown. It slowed temporarily at 0.5 s and then resumed. Meanwhile, when attempting to stop the ball at shorter distances, there was a trend for only one phase of acceleration without any stepping action (i.e., taking a running start). Moreover, temporal changes in the center position of the hand (the third metacarpophalangeal joint) that touched the ball were used to create a diagram depicting the estimated range of time needed to reach the ball. This diagram was able to clarify differences in reaching area with respect to ball height and distance.

著者

松倉 啓太 平嶋 裕輔

出版者

一般社団法人 日本体育・スポーツ・健康学会

雑誌

体育学研究 (ISSN:04846710)

巻号頁・発行日

vol.65, pp.1049-1067, 2020 (Released:2020-12-24)

参考文献数

21

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The aim of this study was to shed light on preparatory sequences performed by elite goalkeepers for defense against shots in response to variations in the position from where a shot at goal is taken, and in the number of touches ahead of the shot. The samples were extracted from videos of shots in all 64 matches of the 2018 FIFA World Cup in Russia. First, to analyze the characteristics of shots in elite games, data on shots from different areas and after various numbers of touches were studied. Then, to analyze the preparatory sequences taken by goalkeepers to defend against those shots, the shots were classified into 6 groups based on ‘the presence or absence of a specific prejump’, ‘a change in the distance between the feet during the preparation period’, and ‘whether the goalkeeper was still in a moving position or had completed the move’. The results of this analysis of the characteristics of the elite game made it possible to divide the positions from where shots were taken in 2 types, based on the probability of the shot being on target and the probability that a goal would be scored. In addition, it was shown that when one-touch shots were on target, it was difficult for goalkeepers to defend against them. Next, as an overall trend, the most frequent preparatory sequence performed by goalkeepers was to prepare for a shot with a slight jump in order to widen the distance between the feet after they had finished moving into position. In addition, a breakdown of the preparatory sequences for various numbers of touches ahead of the shot revealed that – for onetouch shots – a proportion of goalkeepers moved into position until immediately before the shot was taken. Overall, from these analyses, it was concluded that elite goalkeepers must engage in different preparatory sequences depending on the circumstances of the shot.

著者

桐生 習作 向後 佑香 松倉 啓太

出版者

筑波大学体育センター

雑誌

大学体育研究 (ISSN:03867129)

巻号頁・発行日

no.35, pp.69-74, 2013-03