Seiji KUSUBORI - Academia.edu (original) (raw)
Papers by Seiji KUSUBORI
ISBS - Conference Proceedings Archive, 2001
ISBS - Conference Proceedings Archive, 2012
ISBS - Conference Proceedings Archive, Mar 25, 2008
Behavior Research Methods, Apr 13, 2011
International Journal of Sport and Health Science, 2009
Journal of Applied Biomechanics, Nov 1, 2005
The purposes of this study were to (a) describe the racket-arm kinematics and kinetics of the sof... more The purposes of this study were to (a) describe the racket-arm kinematics and kinetics of the soft-tennis smash during match rallies, and (b) assess the characteristics of this smash vs. the laboratory-simulated smash of our previous study. In the current study we recorded soft-tennis smash motions during match play of the 3rd East Asian Games. Racket-arm anatomical joint angular velocity and anatomical joint torque were calculated from 3-D coordinate data of 13 collected motions obtained using the direct linear transformation procedure. The results showed that most of the maximum values of the anatomical joint torques were qualitatively smaller than those of the tennis serve. Peak elbow extension, shoulder internal rotation, and elbow varus torques in match play were significantly greater than values reported for laboratory-simulated conditions. The greater forward swing torques did not result in significantly different racket head velocity, possibly because there was a significantly shorter forward swing phase in match conditions. In particular, a clear peak of the elbow extension torque during the forward swing phase was the most characteristic pattern in the smashes under match conditions, for it was 160% greater than laboratory-simulated conditions. These results supported our hypothesis that racket-arm kinematic and kinetic characteristics of the smash under match conditions differ from those under laboratory-simulated conditions. Possible explanations include the time-pressure conditions of the competitive situation in a match, and the Hawthorne effect (Hudson et al., 1986), both of which alter performance between match conditions and laboratory-simulated conditions.
Both standing smash (SS) and jumping smash (JS) use the overhand swing, but are under different c... more Both standing smash (SS) and jumping smash (JS) use the overhand swing, but are under different conditions from the viewpoint of external force. These two trials were filmed by two synchronized high-speed cameras (250Hz) and 3-D data were obtained using the direct linear transformation procedure. As kinematical data, linear resultant velocity of the racket head and absolute joint angles of upper extremity did not show any significant difference; as for kinetical analysis, joint forces and torques of upper extremity were calculated anatomically. There were no apparent differences in general temporal variations. However, about the shoulder adduction and horizontal adduction torques near initiation of forward swing (IFS), torque peaks of the JS appeared later than that of the SS. Additionally, elbow anterior force of the JS was larger than that of the SS.
The purpose of this study was to examine the function of spin on shot trajectory during flight in... more The purpose of this study was to examine the function of spin on shot trajectory during flight in table tennis. Using film images of an actual match, we computed the 3D coordinates of a ball to analyze the shot trajectories. The theoretical spin-free (TSF) ball trajectories, obtained using a similar approach to Jinji and Sakurai (2006), were compared with the observed shot trajectories. For drive shots, the shot length in the TSF ball was significantly longer than in the observed shots. However, for push shots, among the 30 shots analyzed, 17 of the TSF balls traveled a shorter distance than the observed shots, though difference between them was found not to be significant. The work done by Magnus effect on the ball was estimated by the amount of deflection in vertical direction during flight.
The Proceedings of Joint Symposium: Symposium on Sports Engineering, Symposium on Human Dynamics, 2004
The Proceedings of Joint Symposium: Symposium on Sports Engineering, Symposium on Human Dynamics, 2003
The Proceedings of Joint Symposium: Symposium on Sports Engineering, Symposium on Human Dynamics, 2003
The Proceedings of Joint Symposium: Symposium on Sports Engineering, Symposium on Human Dynamics, 2004
International Journal of Sport and Health Science, 2009
The purpose of this study was to clarify the mechanics involved in making two different shots, na... more The purpose of this study was to clarify the mechanics involved in making two different shots, namely, cross (C) and down-the-line (D), under a two-choice reaction condition in soft-tennis. Using the images from two high-speed cameras, forehand drive motions under these conditions were analyzed with the direct linear transformation procedure. The authors considered that for the selected objects of analysis, the experimental environment significantly affected the actions. Anatomical rotations of the upper extremity and center of gravity (COG) of the subjects during forehand motions were compared between C and D. Some differences were observed in the external rotation of the shoulder and the lateral component of COG. The results were discussed from the perspective of the way in which expert players made ball-racket contact under the choice reaction condition. This was considered to be a high time-pressure condition.
Behavior Research Methods, 2011
Journal of Applied Biomechanics, 2005
The purposes of this study were to (a) describe the racket-arm kinematics and kinetics of the sof... more The purposes of this study were to (a) describe the racket-arm kinematics and kinetics of the soft-tennis smash during match rallies, and (b) assess the characteristics of this smash vs. the laboratory-simulated smash of our previous study. In the current study we recorded soft-tennis smash motions during match play of the 3rd East Asian Games. Racket-arm anatomical joint angular velocity and anatomical joint torque were calculated from 3-D coordinate data of 13 collected motions obtained using the direct linear transformation procedure. The results showed that most of the maximum values of the anatomical joint torques were qualitatively smaller than those of the tennis serve. Peak elbow extension, shoulder internal rotation, and elbow varus torques in match play were significantly greater than values reported for laboratory-simulated conditions. The greater forward swing torques did not result in significantly different racket head velocity, possibly because there was a significant...
ISBS - Conference Proceedings Archive, 2001
ISBS - Conference Proceedings Archive, 2012
ISBS - Conference Proceedings Archive, Mar 25, 2008
Behavior Research Methods, Apr 13, 2011
International Journal of Sport and Health Science, 2009
Journal of Applied Biomechanics, Nov 1, 2005
The purposes of this study were to (a) describe the racket-arm kinematics and kinetics of the sof... more The purposes of this study were to (a) describe the racket-arm kinematics and kinetics of the soft-tennis smash during match rallies, and (b) assess the characteristics of this smash vs. the laboratory-simulated smash of our previous study. In the current study we recorded soft-tennis smash motions during match play of the 3rd East Asian Games. Racket-arm anatomical joint angular velocity and anatomical joint torque were calculated from 3-D coordinate data of 13 collected motions obtained using the direct linear transformation procedure. The results showed that most of the maximum values of the anatomical joint torques were qualitatively smaller than those of the tennis serve. Peak elbow extension, shoulder internal rotation, and elbow varus torques in match play were significantly greater than values reported for laboratory-simulated conditions. The greater forward swing torques did not result in significantly different racket head velocity, possibly because there was a significantly shorter forward swing phase in match conditions. In particular, a clear peak of the elbow extension torque during the forward swing phase was the most characteristic pattern in the smashes under match conditions, for it was 160% greater than laboratory-simulated conditions. These results supported our hypothesis that racket-arm kinematic and kinetic characteristics of the smash under match conditions differ from those under laboratory-simulated conditions. Possible explanations include the time-pressure conditions of the competitive situation in a match, and the Hawthorne effect (Hudson et al., 1986), both of which alter performance between match conditions and laboratory-simulated conditions.
Both standing smash (SS) and jumping smash (JS) use the overhand swing, but are under different c... more Both standing smash (SS) and jumping smash (JS) use the overhand swing, but are under different conditions from the viewpoint of external force. These two trials were filmed by two synchronized high-speed cameras (250Hz) and 3-D data were obtained using the direct linear transformation procedure. As kinematical data, linear resultant velocity of the racket head and absolute joint angles of upper extremity did not show any significant difference; as for kinetical analysis, joint forces and torques of upper extremity were calculated anatomically. There were no apparent differences in general temporal variations. However, about the shoulder adduction and horizontal adduction torques near initiation of forward swing (IFS), torque peaks of the JS appeared later than that of the SS. Additionally, elbow anterior force of the JS was larger than that of the SS.
The purpose of this study was to examine the function of spin on shot trajectory during flight in... more The purpose of this study was to examine the function of spin on shot trajectory during flight in table tennis. Using film images of an actual match, we computed the 3D coordinates of a ball to analyze the shot trajectories. The theoretical spin-free (TSF) ball trajectories, obtained using a similar approach to Jinji and Sakurai (2006), were compared with the observed shot trajectories. For drive shots, the shot length in the TSF ball was significantly longer than in the observed shots. However, for push shots, among the 30 shots analyzed, 17 of the TSF balls traveled a shorter distance than the observed shots, though difference between them was found not to be significant. The work done by Magnus effect on the ball was estimated by the amount of deflection in vertical direction during flight.
The Proceedings of Joint Symposium: Symposium on Sports Engineering, Symposium on Human Dynamics, 2004
The Proceedings of Joint Symposium: Symposium on Sports Engineering, Symposium on Human Dynamics, 2003
The Proceedings of Joint Symposium: Symposium on Sports Engineering, Symposium on Human Dynamics, 2003
The Proceedings of Joint Symposium: Symposium on Sports Engineering, Symposium on Human Dynamics, 2004
International Journal of Sport and Health Science, 2009
The purpose of this study was to clarify the mechanics involved in making two different shots, na... more The purpose of this study was to clarify the mechanics involved in making two different shots, namely, cross (C) and down-the-line (D), under a two-choice reaction condition in soft-tennis. Using the images from two high-speed cameras, forehand drive motions under these conditions were analyzed with the direct linear transformation procedure. The authors considered that for the selected objects of analysis, the experimental environment significantly affected the actions. Anatomical rotations of the upper extremity and center of gravity (COG) of the subjects during forehand motions were compared between C and D. Some differences were observed in the external rotation of the shoulder and the lateral component of COG. The results were discussed from the perspective of the way in which expert players made ball-racket contact under the choice reaction condition. This was considered to be a high time-pressure condition.
Behavior Research Methods, 2011
Journal of Applied Biomechanics, 2005
The purposes of this study were to (a) describe the racket-arm kinematics and kinetics of the sof... more The purposes of this study were to (a) describe the racket-arm kinematics and kinetics of the soft-tennis smash during match rallies, and (b) assess the characteristics of this smash vs. the laboratory-simulated smash of our previous study. In the current study we recorded soft-tennis smash motions during match play of the 3rd East Asian Games. Racket-arm anatomical joint angular velocity and anatomical joint torque were calculated from 3-D coordinate data of 13 collected motions obtained using the direct linear transformation procedure. The results showed that most of the maximum values of the anatomical joint torques were qualitatively smaller than those of the tennis serve. Peak elbow extension, shoulder internal rotation, and elbow varus torques in match play were significantly greater than values reported for laboratory-simulated conditions. The greater forward swing torques did not result in significantly different racket head velocity, possibly because there was a significant...