• Korean Journal of Applied Biomechanics
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• v.28 no.2
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• pp.69-78
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• 2018

Objective: The purpose of this study was to investigate the feasibility of a new vault technique through a kinematic comparison of the YANG Hak Seon and Yeo 2 vaults. Method: The photographic images of the YANG Hak Seon and Yeo 2 vaults were collected using a high-speed camera, and their kinematic characteristics were analyzed using three-dimensional image analysis. Results: During the post-flight phase of the Yeo 2 and YANG Hak Seon vaults, the time of flight, height of flight, and flight distance were similar. At the peak of the post-flight phase, the trunk rotation angle of the YANG Hak Seon vault rotated $457^{\circ}$ more than did the Yeo 2 vault. During the post-flight descending period, the twist velocity of the trunk was much faster with the YANG Hak Seon vault ($1,278^{\circ}/s$) than with the Yeo 2 vault ($1,016^{\circ}/s$). Conclusion: To succeed in the new technique, the average twist velocity during post-flight must be maintained at $1,058^{\circ}/s$ and the twist velocity must be increased from the ascending phase.

• Korean Journal of Applied Biomechanics
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• v.16 no.4
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• pp.165-173
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• 2006

The purpose of this study was to analyze Yurchenko's 900 degree twist technique between the highly scored and the lowly scored subjects during the 2003 TaeGu Universiad Championship. The following results was obtained by analyzing horizontal, vertical and resultant velocities on 1st, 2nd, 3rd and 4th phases. The highly scored subject took longer total performance time but shorter time in 2nd and 300 phases. The highly scored subject also took longer performance time in 4th phase. In the board contact phase the highly scored subject had bigger elbow joint angle and shoulder joint angle. The highly scored subject had longer flying time and had more higher vertical height but lower horizontal and resultant velocities on 4th phase.

• Korean Journal of Applied Biomechanics
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• v.13 no.3
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• pp.47-65
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• 2003

The purpose of this study was to investigate the differences of the kinematical and the kinetical factors that calculated from preflight to postflight of salto forward straight 3/2 turn motion between skitters and less-skitters. four S-VHS video cameras operating at 60Hz were used to record the performances. five elite male gymnasts were participated in this study as subjects. three-dimensional coordinates of 20 body landmarks during each trial were collected using a Direct Linear Transformation method. The digitized body landmarks were smoothed using a Butterworth second order with low pass digital filter and a cutoff frequency of 10Hz. 1. A skitter, got a high score for performance, showed shorter time and faster horizontal velocity than a less-skitter at the board contact. also, a skitter extended quickly his knee and hip joint after contacting board for preflight phase. 2. A skitter revealed faster time and horizontal velocity the vault from taking off board than a less-skiller. A skitter took a long time and high distance to get the vertical peak compared with a less-skiller. 3. For the second phase, a skitter, who executes the most optimal motions among the subjects, displayed a long flight time, a high height, and a far flight distance as well as maintaining consistent horizontal speed even at the peak of post flight. On the other side, a less-scorer displayed a slow vertical velocity, distance and a short time at the point of take-off from vault as well as low height at the peak of post flight.

• Korean Journal of Applied Biomechanics
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• v.18 no.4
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• pp.201-207
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• 2008

The purpose of this study was to examine the Roche technique performed by three male subjects in 2003 Taegu World Students Game. Conclusions are as followed. If the angular momentum was increased to counter-clockwise on voulting, the momentum acted like an interrupting factor of body spinning force. The biggest body angle was at VTD phase and the smallest was at BTO phase. At the phase of contacting on vaulting board and taking off from the vaulting board, the biggest personal angle difference between VTD and BTO was found. As the Roche technique was needed not only to fly high but also to increase body spinning rate, the projection angles of Roche technique were showed smaller than those of Cuervo technique. The angular velocity was peak during 2 times forward turn phase. The angular momentum was influenced by angular velocity from BTO and VTD phase.

• Korean Journal of Applied Biomechanics
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• v.14 no.1
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• pp.13-26
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• 2004

The purpose of this study was to investigate the differences of the kinematical and the kinetical factors that calculated from preflight to preflight of salto forward straight 3/2 turn motion between skillers and less-skillers. four S-VHS video cameras operating at 60Hz were used to record the performances. Five elite male gymnasts were participated in this study as subjects. Three-dimensional coordinates of 21 body landmarks during each trial were collected using a Direct Linear Transformation method. The raw 3-D coordinates of the 21 body landmarks were smoothed using a second order lowpass, recursive Butterworth digital filter and a cutoff frequency of 10Hz. Load cells attached on the beneath of a board were used to attain the kinetic variables. It was found that the more angular momentum in the longitudinal axis, the less vertical velocity and these angular momentum effected the height of peak in the preflight. Also, it was revealed that the larger angular momentum in the medio-lateral axis was rather than it in the longitudinal axis to increase vertical height and rotation force of the body. For the reaction force of springboard, the vertical and the horizontal reaction force were 16.52BW and 3.45BW, respectively. It was found that the higher value of the vertical reaction force induced the faster vertical velocity and the higher an ar momentum. of the whole body center of gravity.