• Korean Journal of Applied Biomechanics
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• v.21 no.5
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• pp.573-584
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• 2011

The purpose of this study was to perform a kinematic analysis of the high jump techniques of the three men's medalists at the 2011 IAAF Championships in Daegu (August 27-September 4, 2011). In particular, a three-dimensional coordinates method was used to analyze the last three strides before touchdown, the touchdown techniques, and the movements after takeoff toward the bar. An analysis of the, data for the biomechanical characteristics of the world's best high jumpers could contribute to an improvement in the performance of a national high jumper. The first conclusion of the data analysis was that the arm movements of the gold medalist, J. Williams, had a single arm form, whereas the arm movements of the other medalists were a double arm form. Second, the difference in the knee joint angles upon touchdown and toe-off was $10^{\circ}$. Third, J. Williams achieved his maximum CM height after takeoff (1.26 m) using the maximum flexion of his knee joint. Fourth, the foot contact duration of A. Dmitrik (0.11 s) was the shortest among the medalists, and the ratio for his transformation of horizontal velocity to vertical velocity was the greatest (75.25%) among the three. Last, the maximum CM height of T. Barry was the greatest, and his foot contact duration was the longest.

• Nutrition Research and Practice
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• v.17 no.4
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• pp.762-779
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• 2023

BACKGROUND/OBJECTIVES: Mediterranean diet is an environmentally friendly and healthy diet model. The diet offers many vegetables, fruits, nuts, and olive oil to consumers. In addition, it provides moderate amounts of fish and chicken, smaller quantities of dairy products, red meat, and processed meat. The Mediterranean diet has a high anti-inflammatory and antioxidant content, and it causes many physiological changes that can provide a physical performance advantage. This study examined the effects of a 15-day menu, which was planned using foods with a low acid load within the Mediterranean diet rules, on the exercise performance, lactate elimination, anthropometric measurements, and body composition. SUBJECTS/METHODS: Fifteen professional male athletes between the ages of 13 and 18, who were engaged in ski running, were included in the experimental study. Dietary intervention was applied for 15 days. The athlete performances were evaluated by applying the vertical jump test, hand grip strength, 20 meters shuttle run test, and Borg fatigue scale. After the shuttle run test (every 3 min for 30 min), blood was drawn from the finger, and the lactate elimination time was calculated. Performance and lactate measurements, body analysis, and anthropometric measurements were taken before and after dietary intervention. RESULTS: The vertical jump height and hand grip strength increased after the intervention (P < 0.05). The test duration, total distance, the number of shuttles, and maximum oxygen consumption parameters of the shuttle run test increased (P < 0.05). After the intervention, the athletes' perceived fatigue scores decreased in several stages of the shuttle run test (P < 0.05). The lactate elimination time and athlete's body composition were similar in repeated measurements (P > 0.05). In the last measurements, the upper middle arm circumference decreased while the height of the athletes increased (P < 0.05). CONCLUSIONS: These results show that the Mediterranean diet is a safe and feasible dietary approach for aerobic performance and strength increase.

• Korean Journal of Applied Biomechanics
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• v.25 no.1
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• pp.1-10
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• 2015

Objective : The purpose of this study was to find some kinetic variable's relationships between personal records and low records in female high jump. Methods : Collected data of the subjects(N=8, ages: $25.5{\pm}1.85$, height: $173{\pm}5.83$, mass: $54.75{\pm}6.36$ personal record: $1.71{\pm}0.04$, low record: $1.62{\pm}0.03$) were used for the last three strides and take-off phase. Five video cameras set in 30frames/s were used for recording. After digitizing motion, the Direct Linear Transformation(DLT) technique was employed to obtain 3-D position coordinates. The kinematic and kinetic factors of distance, velocity, angle, impulse, jerk variables were calculated. A paired t-test was applied for the difference of variables between personal records and lower records and for correlation with performances and variables. The significance level was accepted at p<.05. Results : There was no relationship between pattern of stride and performance. However, rate of change of velocity was related with cental of mass height(CMH) at peak point(PP). Knee, hip, backward lean, foot plant, approach and take off angle showed no difference between best record and low record. Vertical impulse momentum also showed no difference between performances. Conclusion : According to a t-test result, there were significant differences in CMH at PP and jerk at touch down between best record and low record.

• Korean Journal of Applied Biomechanics
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• v.18 no.1
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• pp.53-62
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• 2008

The purpose of this research was to analyze the kinematics of the 205B movement in platform diving. For the experiment, 2 athlete from the national diving team were chosen as the subject and two S -VHS video cameras were used. For this diving players preparing for the olympics participated. It was shown that the mean total took $1.112{\pm}0.12s$. In order to perform better, the divers time must be increased, at take off and rotation must be done high up and the horizontal distance must be shorted to main entrance of the water. To enter the water safely, the jump has to be high, the horizontal speed slow and the vertical speed as fast as possible. At E1 the lower limbs change in speed should decrease and after the rotation begins at E2. At take off, the jump is more important than the rotation for the performance of the dive. At take off, the trunk angular velocity was high, and this was needed to jump high for moment of inertia for rotation because for efficient jumping the upper body has to spread out and increase the height of the center of mass.

• Korean Journal of Applied Biomechanics
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• v.19 no.3
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• pp.519-528
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• 2009

The effects of taping on the use of such measures for prevention have already been comprehensively described in the literature. However, few studies have analyzed ground reaction forces and postural stability with functional ankle instability subject during dynamic activities with ankle taping The purpose of this study was to identify the effects of ankle taping on ground reaction force and postural stability during jump landing. Fourteen players who has ankle instability were participated in this study. we used vicon and force platform. The application of taping who has ankle instability decreased DF and inversion angular velocity and peak vertical ground reaction force during landing. It also improved A-P cop, M-L cop in stability. The findings of this study support the use of taping as part of injury prevention for subject with functional ankle instability in clinical setting.

• Journal of Ocean Engineering and Technology
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• v.23 no.4
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• pp.12-18
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• 2009

The present study focused on the compressibility of partially filled fluids in a sloshing tank. Filling ratios ranging from 18% to 26% were used to find compressible impact on a vertical wall. The model test was for 1/25 scale of a 138 K LNGC cargo tank. To investigate the two dimensional phenomenon of sloshing, a longitudinal slice model was tested. A high speed camera was used to capture the flow field, as well as the air pocket deformation. The pressure time history synchronized with the video images revealed the entire compressible process. Three typical impact phenomena were observed: hydraulic jump, flip through, and plunging breaker. In particular, the pressure time history and flow pattern details for flip through and plunging breaker are presented.

• Korean Journal of Applied Biomechanics
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• v.16 no.1
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• pp.139-149
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• 2006

This study is to analyze the kinematic variables of inward $1{\frac{1}{2}}$ somersault in platform diver. For the manner, 3 people form the national diving team in the year 2000were chosen as the subjects and two S-VHS video cameras set in 60frames/sec were used for recording their motions. Coordinated raw positions data through digitizing are smoothing by butter-worth's low-pass filterin method at a cut off frequency 6.0Hz. and the direct linear transformation(DLT) method was employed to obtain 3-D position coordinates. The conclusions were as follows. However, horizontal distance which is the change of the COG, form the point of the jump to the point of Event 3 where the player is out of the board range completely, Subject B showed 105.1cm and 71.1cm of the vertical distance which are shorter horizontal distance and higher vertical distance, thus, took a great advantage of the position to prepare for the entry. Therefore, if a player takes higher position by speeding up the vertical velocity at the moment of the jumping off the board, and stays in the air longer, the player can have more time to show his skill. Because of the use of the characteristics of the inward somersault, keeping the safe distance form the board is important but in order to higher the completeness, it is ideal to keep the horizontal distance little over 100cm. Also, the angles of shoulder and elbow from Event 1 to 4, depending on swing of the arms, motions in the air, getting ready for the entry, showed some difference individual by individual, according to the velocity of the thigh and shank showed much difference while getting ready and take-off, and it's because of the individual's different bending and straightening for horizontal and vertical distance.

• Korean Journal of Applied Biomechanics
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• v.21 no.1
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• pp.97-105
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• 2011

The purpose of this study was to investigate the kinetic factors of Stefan holm's take-off motion and provide the technical data. Collected data of the subject(height: 181 cm, weight: 71 kg, record: 230 cm) were used for the last two strides and take-off phase. The results were as follows: The vertical impulse force was 2044.8 N which was 2.49 times and the anterior-posterior impulse force was -1306.4 N which was 1.88 times of the subject's weight. The take-off leg angular velocities($\omega_x,\;\omega_y$) were switched drastically from clockwise to count clockwise direction between two-step touchdown and take-off. The highest jerk of the take-off foot was 368.97 m/s3 during the two step take-off and the take-off foot made an impact to the ground with 1225.07 m/s3 during the one step touchdown.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1427-1432
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• 2008

This paper describes the locomotion of a water jumping robot which attempts to emulate the fishing spider’s ability to jump on the water surface. While previous studies of the robots mimicking arthropods living on water were focused on recreating their horizontal skating motions, here we aim to achieve a vertical jumping motion. The robot jumps by pushing the water surface with rapidly released legs which were initially bent. The motion is triggered with a latch driven by the shape memory alloy actuator. The robot is capable of jumping to the maximum height of 26mm. Jumping efficiency, defined the maximum jumping height on water over the maximum jumping height on rigid ground, is 0.26 This work represents a first step toward robots that can locomote on water with superior versatility including skating and jumping.

• Proceedings of the Korea Contents Association Conference
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• 2005.11a
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• pp.247-253
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• 2005

In this paper, I was undertaken to identify factorial structure of physical fitness components for male high school Taekwondo players. In order to accomplish this purpose, the selected 8 physical fitness test were conducted to 50 male high school Taekwondo players. For the concretely, this study was conducted to physical fitness battery was grip strength, vertical jump, standing trunk flexion, sit-ups, closed eyes foot balance, 10m shuttle run, 50m run, and 1600m run. Factor analysis was applied for analyzing factorial structure of each physical fitness components.