- 著者
- Gen Horiuchi Shinji Sakurai
- 出版者
- Japan Society of Physical Education, Health and Sport Sciences
- 雑誌
- International Journal of Sport and Health Science (ISSN:13481509)
- 巻号頁・発行日
- vol.14, pp.94-101, 2016 (Released:2017-03-17)
- 参考文献数
- 19
- 被引用文献数
- 4 6
The purpose of this study was to identify mechanisms to increase bat head speed in baseball batting, from the view-point of kinetics. The batting motion of ninety-nine amateur baseball players was recorded with a motion capture system, and the kinematics and kinetics of the bat were analyzed. The bat's rotational power increased with the torque exerted on the bat's grip. However, torque and rotational power declined just prior to impact. It can be interpreted that these declines arise from a decrease in torque exerted by the wrist's periarticular muscles as the bat's rotational velocity increases (muscle force-velocity relationship). On the contrary, the bat's translational power increased just prior to impact. Judging from the relationship between the force exerted on the bat's grip in the direction of the bat's long axis and the bat head speed, the bat's translational power seems to depend on the bat's grip velocity in the direction of the bat's long axis. It was revealed that the bat's energy, by the application of rotational and translational power at different times, contributes to an increase in bat head speed in baseball batting.
- 著者
- Naoki MURASE Gen HORIUCHI Katsuhiro SUMI Kenji HORIYAMA Sinji SAKURAI
- 出版者
- Japan Society of Physical Education, Health and Sport Sciences
- 雑誌
- International Journal of Sport and Health Science (ISSN:13481509)
- 巻号頁・発行日
- pp.201611, (Released:2017-05-12)
- 参考文献数
- 14
The objectives of the present study were: to examine the relationship between kendo competition levels and men strike times in 20 university kendo club members; and to determine factors for shortening men strike times. LED lamps were attached to the men and the kote (the strike targets), and subjects struck in the direction of the lit LED lamp with maximal effort from a distance of 2.30 m. Phase times, movements, and ground reaction force on both feet were analyzed. The results were as follows. 1. Subjects of higher competition levels tended to demonstrate shorter men strike times. Reaction times, movement times, and shinai upswing phase time also tended to be shorter. 2. Factor for shortening men strike times in the upswing phase consisted of the following: lifting the right foot from the ground quickly, simultaneously pushing off the ground with great force with the left foot, quickly lifting the right thigh forward while moving the body forward, and to increase the range of upswing motion of the shinai with high velocity. In the downswing phase, the shinai should be swung at a higher velocity, and the left shoulder should be flexed more when striking.