철봉에서 몸펴 2회전 뒤돌며 2회 비틀어 내리기 기술의 운동역학적 분석 = A Biomechanical Analysis of the Double Twist and Backward Somersault in Layout Position on the Horizontal Bar

다국어 초록 (Multilingual Abstract)

The purpose of this study was to provide kinematic and kinetic data of the double twist and backward somersault in layout position(DTBS) as a dismounting technique on the horizontal bar. Five DTBS of four national represetative gymasts were filmed by two high speed Locan cameras at 100 frame per second. Two-dementional position data of fifteen Iandmark of the body were digitized and smoothed by the Butterworth low pass digital filtering method with cut off frequency 6HZ. Antrophometric data Chung was used to culculate COG and angular momentum. Kinematic and kinetic data were obtained by using the three dimensional DLT method. Based on the result of this study, the following conclusions were made. 1) It showed that the height of COG at release was 2.638m and the horizental distance at release was 0.804m. The maximum hight of COG in the airbone was 3.658m. The average height of COG at landing was 1.019m and the horizontal distance was 2.003m. On the otherhand, the release angle of COG was 76.4deg and the landing angle was 84.88deg. The COG horizontal velocity at release was 1.073m/sec and vertical velocity was 4.439m/sec. At landing, the COG velocity was 0.528m/sed in the horizontal direction and 5.892m/sec in the vertical direction. 2) It appeared that the tight and left shoulder joint angle at release were 119.4deg and 115.9deg respectively, and were 73.2deg at landing and 72.4deg. The right and left elbow joint angle were 156.9deg and 163.5deg at release, and 140.4deg and 141.1deg at landing By extending quickly the shoulder and the elbow joint just before landing, it was possible to reduce the rotating velocity and to land with stability. . On the other hand, the right and left hip joint angle were 146.0deg and 149.7deg at release, and 125.3deg and 115.3deg at landing. The hip joint was flexed extremely in order to land because of incompleting rotating in airborne. 3) The total angular displasement rotated in somersault and twist were 521.6deg and 638.3deg, and the average angular velocity of somersault and twist were 453.3deg/sex and 529.9deg/sec respectivly. To perform DTBS completly, it was required that the rotating velocity should be increased by the proper beating during dismount gaint swing. 4) The average angular momentum of somersault in succeded trials was 0.48 1/sec and that of twist was 0.20 1/sec, which was 40% of that somersault. This research showed that, to perform DTBS perfectly,both somersault and twist angulat velocity should be mort increased at rerease through increasing momentum.