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등속성 근관절 기능과 근피로도에 근거한 사이클 선수의 근력 불균형 및 페달링 파워에 관한 연구
강영석(Kang, Young-Seok),김정훈(Kim, Jung-Hoon) 한국체육과학회 2014 한국체육과학회지 Vol.23 No.2
The main purpose of this study was to investigate bilateral muscle imbalance based on isokinetic muscle strength in knee and muscle fatigue in elite cyclists observed by electromyographic analysis measured on Wingate test. In doing so, we also found out the corelationship between isokinetic muscle strength and pedaling power. Six elite cyclists were recruited and isokinetic knee and lumbar extension and flexion were measured at 60 degree per sec and muscle fatigue pattern during Wingate test was analyzed to see if any muscle asymetry exists between dominant and non-dominant muscle strength. As a result paired t-test, there was no difference in muscle strength in knee extension and flexion between dominant and non-dominant even though subtle difference in terms of Limb Symetry Index (LSI) was observed. No difference in muscle fatigue pattern in dominant and non-dominant leg observed in Wingate test. Therefore, cyclists involved in cyclic exercise in which right and left limb are relatively uniformly recruited tend to have less or little muscle asymetry between dominant and non-dominant limb.
강영석(Kang, Young-Seok) 한국체육과학회 2014 한국체육과학회지 Vol.23 No.2
In a comparative analysis through motion analysis and ground reaction force of the biomechanic variables found in Wushu-derived butterfly kick as shown in four excellent players and four non-excellent ones, this study has come up with the following conclusion. The study shows that to perform a butterfly kick effectively, it is important to have a long duration of flight with elastic energy accumulated through the lower extremity joints curved by lowering the body’s center of gravity in stomping the feet and then unbending them in flight to heighten the projection height. At this point, one has to get a big ground reaction force and ensure an effective momentum transition from right to left foot to carry out a perfect butterfly kick at its apex.
강영석(Kang, Young-Seok),박찬대(Park, Chan-Dae),박명수(Park, Myoung-Soo) 한국체육과학회 2014 한국체육과학회지 Vol.23 No.4
This study intends to determine the difference between high-performing wushu athletes and non-high performing ones by analyzing vital dynamic factors of the motion of jump lotus kick, which would ultimately aid athletes and coaches to enhance performance. The study found the following conclusions through a quantified analysis. In order to take off from the ground during the motion of jump lotus kick, the athlete must secure the amount of time needed to use the repulsive force of the ground efficiently, and it is important for him or her to project the power from the agonist musculus rectus femoris and musculus gastrocnemius perpendicularly upwards against the ground. Subsequently, the athlete must maximize the air time of the body in order to increase its rotational power on the major axis. At the impact of the motion of jump lotus kick, it is desirable for the athlete to increase the muscular activity of the agonist to deliver the momentum from the proximal segment to the distal segment of the body. When landing, it is efficient to increase the basal area and secure stability by lowering the weight of the body.
강영석(Kang, Young-Seok),유태석(Yoo, Tae-Seok) 한국체육과학회 2011 한국체육과학회지 Vol.20 No.6
In this study, it selected 3 persons of the present national team players whose Wushu career of more than 10 years each, and conducted an analysis on the kinematic and kinetical variables with regard to Jump Lotus Kick 720°motion, from which obtained the conclusion as follows. As for the required time, at the phase2, by enlarging the feet-rolling time more and let the ground repulsive force greater, so that an extreme increase of the vertical height is important, minimizing the left-right travelling width of the body pivot, also the movement greatly towards the progressing direction is efficient, and by taking the gesture of very lowering body just before the foot-rolling motion, it was known that at the time after jump-up, the heightening of body pivot let it can quick turning as well as a relaxable touchdown. At the joint angle. in order to secure its altitude, let it accumulates the energy by maximum bending of the polyarticular at E2, and when take-off from the ground, by extending it to maximum, it converts the kinetic energy to the potential energy, and it was displayed as desirable that when foot-kicking, by the lower side bending of the ankle joint, thence increases the rotation velocity. It was appeared that by maintaining the balance of power at the insides of leftㆍright feet, the generating of the kinetic energy able to shoot-up the body higher is important, and by means of the generation likely as the left foot for the impellent power, the right foot for the braking force, respectively, thence as it strengthens the vertical ground reaction force, makes it rising the vertical speed of body also the air-floating height, enlarging the air-floating time, a relaxable landing is efficient.
강영석(Kang Young-Seok),김종선(Kim Jong-Sun) 한국체육과학회 2011 한국체육과학회지 Vol.20 No.3
The main aim of this study was to examine the absolute and relative of some commonly used strength imbalance indices such as concentric hamstring-to-concentric quadriceps ratio(Hcon/Qcon : conventional H/Q ratio), eccentric hamstring-to-concentric quadriceps (Hecc/Qcon : functional H/Q ratio). An additional aim was to examine the reliability of the peak torque, total work/body weight(%WT), average power(AP) of the conventional H/Q ratio and functional H/Q ratio measured using the isokinetic dynamometer(Biodex system4, U.S.A). Twenty-three physical active healthy subject(mean±SD, age 22.2±2.1 years, height 173.6±8.7㎝, weight 71.5±9.8, percent fat 19.5±5.9, BMI 23.6±1.7㎏/㎡) were tested 60°/S, 180°/S concentric contraction and eccentric contration. Peak torque(PT) and percent total work(%TW) were significantly different among conventional and functional H/Q ratio, but average power were not significantly different among conventional and functional H/Q ratio. The evaluation of knee joint function by use of isokinetic dynamometer should comprise data on functional and conventional hamstring:quadriceps ratios as well as data on absolute muscle strength. The agonist-antagonist strength relationship strength for knee extension may better described by the more %total work funtional ratios of eccentric hamstring to concentric quadriceps.
다단 천음속 압축기의 유동 불안정성에 관한 실험적 연구
강영석(Young-Seok Kang),박태춘(Tae-Choon Park),황오식(Oh-Sik Hwang),양수석(Soo-Seok Yang) 한국유체기계학회 2011 유체기계 연구개발 발표회 논문집 Vol.2011 No.11
This study presents unsteady and unstable characteristics of three stage transonic axial compressor, developed by Korea Aerospace Research Institute. As approaching to the unstable operating region at the 103% design speed of the compressor, a modal type stall precursor appears in front of highly loaded 3rd rotor row at first, and it propagates to the upstream. On the contrary, actual stall cell initiates from the stall precursor in front of the 1st rotor row, and it propagates to the downstream of the compressor. After the stall region reached the 3rd stage and stall cell rotates circumferentially about 360deg, it develops to the one dimensional compressor surge mode. It shows a mild surge behaviour with 3~4 Hz frequency. From the test data, it can be suggested that there is a priority to give an optimum blade loading distributions to construct a multi stage transonic axial compressor stages either to secure more stable compressor operating ranges, or to maximize the compressor efficiency.
강영석(Kang, Young-Seok) 한국체육과학회 2012 한국체육과학회지 Vol.21 No.6
The subjects of this study are three outstanding national representative athletes and three non-exceptional athletes that have never won in any competitions. This study quantitatively analyzes the kinetic factors through an electromyography and has produced the following results. The first and second parts when performing a Wushu jump front kick are the approach and take-off parts. During these parts, the muscle flexing of the lower legs are much greater than thigh which causes the forward movement speed to rapidly transfer to the vertical ascension speed so that the height of the jump is increased. To effectively perform a Wushu jump front kick from the moment of taking-off from the surface until the point of maximum height, it is determined that the muscle flexing of the straight muscle of the thigh and the hamstring plays a significant role in maintaining a good form.