• Journal of the Korean Academy of Clinical Electrophysiology
• /
• v.10 no.2
• /
• pp.31-35
• /
• 2012

Purpose : The purpose of this study was to investigate the effect of kinematic variables by analysis of a gait in older. Methods : This study selected nine in older adults with osteoarthritis. The Kinematic variables during walk were compared analyzed using motion analysis. Results : The findings of this study are as follows. Stance time showed significant difference within-subject groups and interaction within-subjects and time. The swing and stride time showed a no significant interaction within-subjects and time. Swing time showed a no significant difference according to time and within-subjects. Stride time showed a significant difference according to time. But, stride time showed a no significant difference according to within-subjects. Conclusion : These findings of this study indicate that when the patients with total knee arthroplasty decreased stability. Therefore, stance and stride time showed increase when walking, because to decrease the weight bearing that is delivered to knee. And swing time showed decrease.

• Journal of Biosystems Engineering
• /
• v.40 no.3
• /
• pp.289-295
• /
• 2015

Purpose: From the perspective of biomechanics, joint moments quantitatively show a subject's ability to perform actions. In this study, the effect of normalization in the fast and asymmetric motions of a golf swing was investigated by applying three different normalization methods to the raw joint moment. Methods: The study included 13 subjects with no previous history of musculoskeletal diseases. Golf swing analyses were performed with six infrared cameras and two force plates. The majority of the raw peak joint moments showed a significant correlation at p < 0.05. Additionally, the resulting effects after applying body weight (BW), body weight multiplied by height (BWH), and body weight multiplied by leg length (BWL) normalization methods were analyzed through correlation and regression analysis. Results: The BW, BWH, and BWL normalization methods normalized 8, 10, and 11 peak joint moments out of 18, respectively. The best method for normalizing the golf swing was found to be the BWL method, which showed significant statistical differences. Several raw peak joint moments showed no significant correlation with measured anthropometrics, which was considered to be related to the muscle coordination that occurs in the swing of skilled professional golfers. Conclusions: The results of this study show that the BWL normalization method can effectively remove differences due to physical characteristics in the golf swing analysis.

• Korean Journal of Applied Biomechanics
• /
• v.19 no.1
• /
• pp.167-177
• /
• 2009

The purpose of this study was to investigate effect of golf shoe design on kinematic variables during golf swing. Five professional male golfers with shoe size 270mm were recruited for the study. Swing motion was collected using 8 high speed camera motion analysis at a sampling of 180Hz. Kinematic variables were calculated by EVaRT 4.2 software. Driver swing was divided into four events; El(adress), E2(top), E3(impact) and E4(finish). Time, peak velocity, velocity of center of mass, velocity of the foot and ankle angle during Phase 1(El-E2), Phase 2(E2-E3), and Phase 3(E3-E4) were analyzed in order to investigate the relationship between golf shoe design and swing performance. The findings indicated that type C golf shoes would be beneficial for stability and control of movement during address and swing performance. Furthermore, faster speed of golf shoes, center of mass, and both feet were observed with Type C golf shoes. It is expected that golfers with Type C golf Shoes provide greater force as they control the center of mass faster and increase rotational force during impact compared to other golf shoes.

• Korean Journal of Applied Biomechanics
• /
• v.17 no.1
• /
• pp.41-52
• /
• 2007

The present study analyzed the two hand backhand stroke motion of six female high school tennis players who won the championship at the National Athletic Meeting in 2006, and drew conclusions as follows. The open angle of the racket at the moment of impact was 90 degree without significant difference among the players, making a wide contact between the ball and the racket. The racket angle was 43 degree at take back and 91 at impact, showing a style of holding the racket rather upright in general. In back swing from the top to the impact, the shoulders and the hips turned by 97 degree and 40 degree, respectively. At the moment of impact, the height of the impact was 54%H, and the position of the impact was 10%H ahead of and 37%H left from the central axis of the body. The right hand made a continental grip and the left hand made a Western or semi Western grip. Through the entire swing motion, the grip angle of the left hand was smaller than that of the right hand, and those who maintained a large grip angle of the right hand at the moment of take back put the racket head slightly farther from the body. In the swing of the racket head from the lowest point to the impact, the vertical length of movement was 11%H and the horizontal length of movement was 60%H, quite long.

• Journal of the Korean Society of Physical Medicine
• /
• v.7 no.3
• /
• pp.293-302
• /
• 2012

Background & Purpose : The purpose of this study is to evaluate the impairment of SVMC(selective voluntary motor control) of the lower extremity by assessing each joints of lower limb and to analyze the motional relationship between each joints of lower limb using SCALE(Selective Control Assessment of the Lower Extremity) during the swing phase of gait cycle in children with spastic diplegia. Method : 11 children with spastic diplegia CP who could walk independently and 10 normal developing children were participated. SCALE(Selective Control Assessment of the Lower Extremity) assessments were conducted for 11 children with CP. Gait analysis were accomplished in all participants. Qualisys motion analysis was used as a statistical tool to assess the motional relationship between hip joint, knee joint and ankle joint in each limb. We used descriptive statistics, cross-tabulation, independent t-test, linear regression to analysis motional relationship between each joints of lower limb using by SPSS ver.17.0. Result : Firstly, there were significant differences in SCALE scores between the cerebal palsy group and the control group in knee joint(p<0.05), but no significant difference in hip and ankle joints during the swing phase of gait cycle. Secondly, the difference of SCALE scores showed no statistical motional difference in knee and ankle joints during the swing phase, and showed significant motional difference in hip joints during the swing phase(p<0.05). Thirdly, there was a liner relationship between the motion of hip and ankle joints during the swing phase. Conclusion : The nature of SVMC(selective voluntary motor control) in each joints of the lower limb may reflect the ability of gait, thus SCALE may be used for assessing and for treating the cerebal palsy patients who are able to walk independently. Also we knew that the impairment of SVMC(selective voluntary motor control) increases from the proximal to the distal joints.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.903-906
• /
• 2005

The purpose of this study was to analyze the muscular force of swing using the soft golf club in comparison with the muscular force of swing using normal golf club. The subject was normal adult (twenties) and performed swing motion using normal and soft golf club. And then we compared muscular power soft golf club with normal golf club of the subject. The muscular power of the subject was measured by MP 100(BIOPAC Systems, Inc.). For the analysis of muscular power of swing using soft golf club, we measured EMG(Electromyography) of the subject. The position of muscle was deltoid, latissimus dorsi, external oblique and rectus abdominis of the upper limbs and rectus femoris, biceps femoris, gastrocnemius and soleus of the lower limbs. The result of experiment, muscle pattern of swing using soft golf club was similar to pattern of swing using normal golf club and muscular power of subjects using the soft golf was smaller than normal golf.

• Korean Journal of Applied Biomechanics
• /
• v.17 no.3
• /
• pp.115-124
• /
• 2007

The purpose of this study was to analyze the kinematics variables of upper limb joint during forehand stroke by swings patterns. Eight high school tennis players were chosen for the study, who have never been injured for last six months, in Busan. They performed horizontal swing and vertical swing that it was done each five consecutive trial in the condition of square, semi-open and open stance. It was filmed by 6 video camera and used with 3-dimensional motion analyzer system. The following kinematic variables were analyzed in relation to angle of joint(shoulder, elbow and wrist joint). The conclusion were as follow: 1. The angle of right shoulder joint represented all event that both swing were shown similar pattern in swing type and stance pattern. 2. All event in the angle of elbow joint had consistent with that except E2, horizontal and vertical swings in square stance. 3. All event in the angle of wrist joint was show to similar pattern except E2, horizontal and vertical swing in open stance.

• Korean Journal of Applied Biomechanics
• /
• v.12 no.2
• /
• pp.17-32
• /
• 2002

The purpose of this study was to find the rational method to analyze golf swing with specific property of club shaft. Three subjects were filmed by two high speed digital cameras with 500 fps. The phase analyzed was downswing of each subject. The three-dimensional coordinates of the anatomical landmarks were obtained with motion analysis system Kwon3d 3.0 version and smoothed by lowpass digital filter with cutoff frequency 6Hz. From these data, kinematic and kinetic variables were calculated using Matlab(ver 5.0) The variables for this study were angular velocity and accelerations, which were calculated and following conclusions have been made : 1) Golf swing time of stiff club is faster than that of regular club. 2) In shoulder joint motion of swing with the stiff club, x-stiff showed mort rapid negative acceleration than that of regular club. 3) In regular club, the velocity of club head would be more effective velocity, which was increasing, than those of other clubs before impact. 4) In wrist joint motion of swing with stiff club, x-stiff club showed faster than regular club in the downswing and impact more rapid negative acceleration.

• Korean Journal of Applied Biomechanics
• /
• v.28 no.2
• /
• pp.87-92
• /
• 2018

Objective: The purpose of this study was to investigate the factors affecting two kinds of bat swing behavior through kinematic analysis. Method: A total of 32 high school baseball players participated in this study. The ball was placed on the tee-ball in a position where the subject could easily swing and the standard bat swing was performed as quickly and as accurately as possible using aluminum bats and wooden bats. Results: The aluminum bat showed a rapid swing speed of about 1.79 m/sec compared to the wooden bat. The speed of the batted ball was found to be significantly greater for the aluminum bat than for the wooden bat. In addition, although the difference between the shoulder-pelvis rotation angle according to the type of bat was not indicated, there was a statistically significant difference between the aluminum bat and the wooden bat in terms of the rotational angular velocity. Conclusion: Even though the results can explain the difference between the bat swing speed and the speed of the batted ball depending on the bat's material, it is difficult to explain the difference depending on the type of bat at the shoulder-pelvis rotation angle. However, shoulder-pelvic rotation angular velocity appears to be higher for the aluminum bat, and the differences in the type of bat is considered to be related to the batting swing factor.

• Korean Journal of Applied Biomechanics
• /
• v.19 no.1
• /
• pp.37-47
• /
• 2009

This study develops a technique training program to enhance the completion of Kolman, the high air flight technique, and applies it to two national athletes of the horizontal bar, one of the gymnastic events, for eight weeks. After that, their improvement was measured through 3D motion analysis to help them elevate their performance. The training program includes swing, hand release, twist, and bar hold, and its implementation produced the results stated below. They were made to practice the motion in the following way. After the hand-standing of giant swing which initiates the motion, they lift their body upward a little bit more. Next, they take their body down almost like a vertical descent and make a deep tap swing. Instead of doing the tap swing which widens the flection of hip and shoulder joints, while body revolution is more emphasized in particular, they release the bar as raising the centroid of their body sufficiently. During the flight, they try to narrow every joint in their body. As a result, the bar's elasticity becomes greatly increased, and since the backing rate of their body gets higher, the centripetal force of the swing is improved that they can release the bar in the higher position. In addition, because they can erect their body faster during the flight, they can perform comfortable twist and revolution in the air. They can also adjust the direction of the flight easily without too much concern for the proper timing of hand release as they rise. Thereby, they can not only maintain adequate distance from the bar for the bar hold but also ensure enough distance for body revolution and twist.