• Korean Journal of Applied Biomechanics
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• v.18 no.2
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• pp.29-39
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• 2008

This study was to provide for Tippelt technique which was a basic technique used in parallel bars. The program was applied to players for 8 weeks. Then it was analyzed by using 3Dmotion Analysis system to seek the difference between before and after using the program. Moreover establish the improvement and trait for newly made program. The program was made up of down-swing, up-swing and composite connection-phase training. Through down-swing training, shoulder angle made extension and chest closed quickly. As a result, players' performance have improved. Through up-swing training, legs kicking to vertical direction and trunk stood up fastly. As a result, players' performance have improved. When going upward, the center of mass must be in control not to have a lot of movement and hip angle extension using the bar is very positive coaching. When coaching composite connection in training from down-swing to up-swing, must have enough air phase time using center of mass vertically to have extension of leg. As a result, players' performance have improved by having increase of air phase time.

• Korean Journal of Applied Biomechanics
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• v.14 no.2
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• pp.27-40
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• 2004

The objective of this study is to identify the kinematic variables of giant swing backward to handstand as well as individual variations of each athlete performing this skill, which in turn will provide the basis for developing suitable training methods and for improving athlete's performance in actual games. For this end, 3 male athletes, members of the national team, who are in ${\Box}{\Box}H{\Box}{\Box}$ University, have been randomly chosen and their giant swing backward to handstand performance was recorded using two digital cameras and analyzed in 3 dimensional graphics. This study came to the following conclusion. 1. Proper time allocation for giant swing backward to handstand are: Phase 1 should provide enough time to attain energy for swing track of a grand round movement. The phase 3 is to throw the body up high in the air and stay in the air as long as possible to smoothen up the transition to the next stage and the phase 4 should be kept short with the moment arm coefficient of the body reduced. 2. As for appropriate changes of locations of body center, the phase 1 should be comprised of horizontal, perpendicular, compositional to make up a big rotational radius. Up to the Phase 3 the changes of displacements of vertical locations should be a good scale and athlete's body should go up high quickly to increase the perpendicular climbing power 3. When it comes to the speed changes of body center, the vertical and horizontal speed should be spurred by the reaction of the body in Phase 2 and Phase 3. In the Phase 4, fast vertical speed throws the body center up high to ensure enough time for in-the-air movement. 4. The changes of angles of body center are: in Phase 2, shoulder joint is stretching and coxa should be curved up to utilize the body reaction. In the Phase 4, shoulder joint and coxa should be stretched out to get the body center as high as possible in the air for stable landing. 5. The speeds of changes in joints angles are: in the Phase 2 should have the speed of angles of shoulder joints increase to get the body up in the air as quickly as possible. The Phase 3 should have the speed of angles in shoulder joint slow down, while putting the angles of a knee joint up to speed as quickly as possible to ensure enough time for in-the-air movement.

• Korean Journal of Applied Biomechanics
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• v.21 no.3
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• pp.317-325
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• 2011

The purpose of this study was to investigate the contributions of body joints to the kinetic energy of the clubhead in the golf swing. Three dimensional swing analysis was conducted on the seven KPGA golfers. The subjects were asked to swing with 45 inches of driver. The work done by body joints were computed by utilizing the inverse dynamics method. The order of work done by the body joints was lumbar > left hip > right shoulder > left wrist > right wrist > right hip at the first phase. At the second phase, the order of work done by the body joints was trunk > left elbow > right wrist > right shoulder > left wrist > right wrist. At the third phase, the order of work done by body joints was lumbar > right shoulder > left shoulder > left elbow > right wrist > right elbow. The sum of the work done by the body joints was lumbar > shoulder > wrist on the average. The kinetic energy of the club head was 430.11${\pm}$24.35 J and the subject's swing efficiency was shown as 31.82${\pm}$4.86% on the average. The contributions of body joints to the kinetic energy of the clubhead was the order of lumbar > upper right shoulder > left elbow > right wrist during the down swing.

• Korean Journal of Applied Biomechanics
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• v.18 no.4
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• pp.143-149
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• 2008

The purpose of this study was to investigate the muscle activities of pectoralis major, upper serratus, lat dorsi, anterior deltoid, rhomboids, infraspinatus, and posterior deltoid using Noraxon 8 channels EMG system during T-ball swing in children with Down syndrome. Five Down syndrome, one healthy children, and one baseball adult player were participated in the study. Down syndrome's children showed higher muscle activity than one healthy children and one baseball adult player during address to backswing and backswing to impact swing phase. While Down syndrome's children showed lower muscle activity than one healthy children and one baseball adult player during impact to follow swing phase. The strength of the pectoralis major and upper serratus muscle may help to improve T-ball swing movement during impact to follow swing phase.

• Korean Journal of Applied Biomechanics
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• v.22 no.3
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• pp.333-339
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• 2012

Freezing of gait is a severely problem in people with Parkinson's disease. The purpose of this study was to investigate the muscle activities of adductor longus, gluteus medius, gluteus maximus, biceps femoris, rectus femoris, gastrocnemius, and tibialis anterior using Noraxon 8 channels EMG system during stop task in patients with Parkinson's disease. Seven parkinson's patients and age matched normal participants were recruited in the study. Filtered EMG signals were rectified, smoothed and integrated. To control for the altered timing and magnitude of activity, iEMG was normalized for time and peak value. The results indicated that the patients with Parkinson showed decreased gait cycle, stance phase, swing phase time, swing phase time ratio and increased stance phase time ratio than normal participants. The patients with Parkinson showed decreased gastrocnemius muscle activity time ratio, while increased tibialis anterior muscle activity time ratio than normal participants. During stance phase before stop, the patients with Parkinson showed relatively lower average and peak iEMG in anterior tibialis and gastrocnemius muscle than normal participants. During swing phase before stop, the patients with Parkinson showed relatively higher average iEMG in gastrocnemius muscle than normal participants. During stop phase, the patients with Parkinson showed relatively lower average and peak iEMG in anterior tibialis and gastrocnemius muscle than normal participants.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.267-271
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• 1997

In this study, swing phase dynamic simulation of above-knee prosthesis is performed. The prosthesis consists of a single axis knee mechanism and pneumatic cylinder. The numerical modelling of the prosthesis is analyzed in two dimensions. The governing equation of thermodynamical pneumatic cylinder model is applied to construct the control of lower limb during swing phase. Knee flexion angle with respect to the orifice diameter of the pneumatic cylinder is produced. This analysis will be very useful to the design of pneumatic cylinder in prosthesis.

• Korean Journal of Applied Biomechanics
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• v.13 no.2
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• pp.13-28
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• 2003

The purpose of this study was to analyze the kinematic characteristics of Ice hockey slap shot. The subjects of this study were four professional ice hockey players. The reflective markers were attached on the anatomical boundary line of body and the subjects were asked to perform the shot. Ariel Performance Analysis System was used to capture and digitize the shooting image, the data were analyzed by LabView 6i. The results were as fellows. 1. The period of the back swing phase was $0.542{\pm}0.062sec$, the down swing phase was $0.28{\pm}0.056sec$ and the total swing time was $0.825{\pm}0.017sec$ 2. The maximum linear velocity of the stick blade for x direction was shown after 7% of impact, for y, z direction were shown before 2%, 8% of Impact. 3. The maximum velocity of each segment for the left arm was $2.35{\pm}0.05m/s$ in the upper arm, $3.56{\pm}0.34m/s$ in the forearm, $4.75{\pm}0.67m/s$ in the hand. 4. The maximum velocity of each segment for the right arm was $4.67{\pm}0.43m/s$ in the upper arm, $7.22{\pm}0.69m/s$ in the forearm, $9.42{\pm}0.89m/s$ in the hand. 5. The angle of left elbow was generally flexed from the ready stance to the impact and was $82.26{\pm}3.45^{\circ}$ the moment of Impact. 6. The angle of the left shoulder was increased ut the down swing phase and was $78.74{\pm}4.78^{\circ}$ on the moment of impact. 7. The angle of the right shoulder was decreased in the down swing phase and increased before the impact. and the angle was $51.28{\pm}3.54^{\circ}$ on the moment of impact.

• Korean Journal of Applied Biomechanics
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• v.30 no.4
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• pp.293-299
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• 2020

Objective: The aim of this study was to investigate the swing and aerial motion of Kovacs, and evaluate the skill level of Kovacs by Korean adult players on horizontal bar. Method: The subjects for this study were 6 male top athletes participated in the 46th National Gymnastics against Cities and Provinces. After the motions of Kovacs were filmed by digital highspeed camcorder setting in 90 frames/s, kinematical data were calculated through DLT method. The variables were computed in the lapse time, the joint angle, the position·velocity of body COG, the inferred tension force of bar, and body COG path were simulated according to skill level of Kovacs. Results: Firstly, it was revealed that the lapse time was 1.19±0.03 s in the swing phase, and 0.83±0.03 s in the aerial phase. Secondly, it was revealed that the shoulder·hip joint motions of S1 and S2 were better than the other subjects in the swing phase, and the knee joint motions of S1 and S2 were better than the other subjects in the aerial phase. Thirdly, it was revealed that the horizontal·vertical velocity of body COG were -1.40±0.03 m/s, 3.80±0.07 m/s respectively, and the vertical positions of S1 and S2 were higher a little than the other subjects. Lastly, the skill level of Kovacs of this subjects was evaluated into 3 steps; excellent, advanced, normal. They need to train the swing motion including a giant circle, and body motions in the air. Conclusion: It would be suggested that Korean domestic players should improve to increase the vertical velocity at release instant and train to control the limbs elaborately in the air.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.9
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• pp.714-723
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• 2003

An effective technique to increase the signal swing and reduce noise is to use fully-differential -circuits. However, design of a common-mode feedback (CMFB) circuit that stabilizes the common-mode output level is essential. In this paper, a general description is given to fully-differential amplifiers with their CMFB loops, then a new error amplifier that is just composed of transistors and stabilizes the DC output level is proposed. We designed a simple and efficient bias circuit that allows the stability and maximum input swing. Simulation result shows the enhanced phase margin and increased differential-mode input swing with a proposed error amplifier.

• Korean Journal of Applied Biomechanics
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• v.14 no.2
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• pp.167-178
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• 2004

The purpose of this study was to describe and compare the selected electromyographical muscle activities of trunk and hip during Professional and Amateur golfer's Iron swing. Using surface electromyography, we evaluated muscle activities in 6 male professional golfers and 6 male amateur golfers during the golf iron swing. Surface electrodes were used to record the level of muscle activity in the right abdominal oblique, left abdominal oblique, right erector spinae, left erector spinae, right rectus abdominis, left rectus abdominis, right gluteus maximus, left gluteus maximus muscles during the golfer's swing. These signals were compared with IEMG(Integrated EMG) which was normalized by %RVC(Reference voluntary contraction). The golf swing was divided into three phases: take away, forward swing-acceleration, follow-through. We observed patterns of trunk muscle activity throughout three phases of the golf swing. The results can be summarized as follows: LES(Left Erector spinae) had statistically significant difference in take away and forward swing-acceleration phases. It was showed no significant difference in follow-through phase.