• Korean Journal of Applied Biomechanics
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• v.19 no.1
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• pp.87-98
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• 2009

This study was conducted to compare biomechanical differences in throwing movement between skilled and unskilled high school students using three-dimensional analysis system with a force platform. The findings indicated that skilled students showed shorter throwing time, faster horizontal speed of (1) the center of mass at heel contact of left foot, (2) the forearm throughout swing phase, (3) the hand after heel contact while unskilled students showed faster horizontal speed of, (1) the center of mass after heel contact and (2) the hand at heel contact of left foot. Skilled students showed greater (1) shoulder angle during throwing, (2) elbow angle after take off of foot, (3) peak vertical ground reaction force during throwing and (4) peak anterior-posterior ground reaction force at heel contact of right foot. While skilled students showed leaning backward of the trunk during throwing, unskilled students showed leaning forward during release phase with leaning backward before release.

• Journal of the Korean Applied Science and Technology
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• v.38 no.4
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• pp.1143-1155
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• 2021

The results of the analysed to compare the kinematic variables of backhand backwall boast shot motion between the expert and novice subjects through three dimensional cinematography. First, the expert took shorter time than novice to finish the motion. Second, the racket of expert showed side-horizontally higher, vertically lower and front-horizontally higher displacement than novice in the downswing phase. Third, the racket of expert showed vertically and front-horizontally lower displacements than novice during the follow through phase. Fourth, the velocity of racket was faster for the novice. Five, the velocity of lower arm was faster for the novice.

• The Journal of the Korea Contents Association
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• v.14 no.9
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• pp.131-140
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• 2014

The purpose of this study was to kinetic analysis of using the skill of breathing korean dance movement will be to perform. To achieve the research objectives cheoyongmu Nakhwayousu the operation was performed. The selection of subjects like the following: Five people were skilled use of breathing and five unskilled person. The results are as follows. The skilled and the unskilled were no significant differences in the duration time. And the skilled and the unskilled z-axis position of the center of mass, there was a significant difference (p<.05). The skilled and the unskilled y-axis velocity of the center of mass, there was a significant difference of event 1 and event 4 (p<.05). And z-axis velocity of the center of mass, there was a significant difference of event 3 (p<.05). And the skilled and the unskilled Fx of GRF, there was a significant difference of event 2 and event 4 (p<.05). And Fy of GRF, there was a significant difference of event 1 and event 5 (p<.05). And Fz of GRF, there was a significant difference of event 4 (p<.05).

• Korean Journal of Cognitive Science
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• v.29 no.2
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• pp.121-135
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• 2018

Dancers' motions are perceived by observers through visual processes with visual information forming the basis for the observers' appreciation and evaluation of the dancers' motions. There have been many discussions as to whether or not observers' personal athletic capabilities form an essential basis for accurate assessment of the motions of others but, so far, no valid conclusions have been reached. The purpose of this study is to investigate how the ability to predict motions of others varies depending on the athletic expertise of the observers. Participants of this research were ballet dancers of varying athletic expertise. Twenty seven participants were divided into three groups with nine in each: beginners, intermediate experts and experts. The participants watched the same dance video and then evaluated whether the motion would be successful or not. The movement related visual information required to evaluate the success of the motion was systematically adjusted by controlling the length of the video. Using the temporal occlusion method, this study measured the response accuracy of the participants by category of expertise. Under the circumstance with insufficient visual information to utilize, the experts showed higher rates of correct response than the intermediate experts and the beginners. The beginners showed higher rates of wrong response than the experts and the intermediate experts. These results showed that the ability to predict success or failure of a dance motion varied depending on motion expertise of the observers, although they had similar level of expertise in perception. Participants considered to have high athletic expertise showed high prediction ability on the result of the motion. In addition, high expertise in perception reduced the likelihood that participants would make hasty responses under the circumstance with insufficient information and helped to reduce wrong response rate. In conclusion, this study showed that motor expertise and perceptual expertise contribute to prediction accuracy of observed motions.

• Korean Journal of Applied Biomechanics
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• v.19 no.4
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• pp.729-738
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• 2009

The purpose of this study was to analyze the impact accuracy and kinematic parameters of skill level and eye-tracking type during putting strokes. For comparison, five elite golfers and five novice golfers participated in this study. Three-dimensional kinematic data were collected for each subject while 10 putting trials were performed for each skill level and eye-tracking type. The APAS system was used to compute the impact accuracy and kinematic parameters of putter heads. The putting stroke was divided into three phases: back swing, downswing, and follow-through. The findings indicated that significant differences were found in skill level as it affected the rate of success. For impact accuracy and the displacement of putter heads, a significant difference was found for the skill level, particularly in backs-wing and follow-through. In addition, the displacement of the putter head had a greater influence on stroke accuracy than on velocity.

• Korean Journal of Applied Biomechanics
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• v.19 no.2
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• pp.287-296
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• 2009

This is written to present basic shot information among iron clubs and information of weight shift, because previous study conducted on all clubs was rut enough. This article is about shot analysis of iron club 3,4,5,6,7,8,9 and weight movement, conducted on four skilled golf players and four students who major in golf and are less than three years. The analysis of long and short irons showed statistically meaningful different results for all the participants but iron clubs of 3,4,5 didn't in head speed and ball speed. The skilled group showed better results in head speed, ball speed and direction, Launch angle than the unskilled group. In weight shift movement analysis, the unskilled group moved, on back swing top, their more weight(65.36%) but the skilled group was on their left foot (70.21%)when clubs were on impact moment. It shows that the skilled group put on power more efficiently by moving weight.

• Korean Journal of Applied Biomechanics
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• v.19 no.3
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• pp.467-479
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• 2009

The purpose of this study was to present the quantitative data which riders can utilize teaching field by comparison analysis of kinematics according to skill level of rider during 2 strides rising trot with the JeJu's-Horse. Participated subjects was consisted of total 10 riders(unskilled: n=5, skilled: n=5). The method of experiment & analysis was based on 3D cinematography. Variables were consisted of temporal, linear & angular kinematics by each event & phase. The skilled assigned more ratio of elapsed time in air than support phase, had the less range of motion in up-down direction and more consistent velocity in lateral & forward direction and performed periodic up-down movement with alignment in vertical direction according to elapsing of phases. The skilled more flexed at elbow and extended backwardly according to elapsing of phases, while more flexed forwardly at hip & knee and plantarflexion at ankle. The skilled postured backward extension but the unskilled do forward flexion. That is, It was considered that the unskilled continued more unstable posture than the skilled during 2 strides in rising trot.

• Journal of the Korea Convergence Society
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• v.6 no.4
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• pp.249-255
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• 2015

The study was to investigate the effects of stimulus velocity and passer's skill level on anticipation timing performance. Fourteen subjects(seven novices and seven experts) were required to make a total 12 passes in coincidence with an experimentally manipulated moving light signal in randomly presented three different conditions(4m/s, $3m/s{\rightarrow}5m/s$, $5m/s{\rightarrow}3m/s$). Results of analyses showed that absolute error(AE) and constant error(CE) were greater in constant acceleration of the moving stimulus. In addition, experts were more accuracy and consistency than novices on absolute, constant and variable error(VE). These findings indicated that stimulus velocity served as the major determination of anticipation timing performance of passing.

• Korean Journal of Applied Biomechanics
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• v.19 no.1
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• pp.127-138
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• 2009

The purpose of this study was to investigate range of motion (ROM) and muscle activities according to the skills of Surya Namaskara in Vinyasa Yoga. Six females (skilled 2, unskilled 4) of university students participated in this experiment. The research factors were ROM and muscle activities for static poses on Surya Namaskara in Vinyasa Yoga. The six infrared cameras (Oqus 300, Qualisys Inc, Sweden) and Zero Wire EMG (Aurion, Italy) were used to acquire raw data, and the Qualisys Track Manager and Noraxon (MyoResearch XP Master Edition, USA) were used to process data. The %MVIC and ROM were analyzed with Visual 3D (C-Motion Inc, USA) and Noraxon. In conclusion, ROM and %MVIC between two groups were remarkable different according to the static poses of Yoga, therefore instructors have to provide step-by-step information that was suitable to themselves (ROM and EMG of poses).

• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.197-206
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• 2002

The purpose of this study was to investigate the putter head movement during the putting strokes. Highly skilled 5 golfers(less than 3 handicaps) and 5 novice golfers(having no golf experience) participated in this study. A target distance was 3 m. Movements of the putter head were recorded at 60 Hz with two video cameras. The results showed that the novice golfers moved the club significantly longer than the expert golfers(p<.0001). Accoring to a movement time, novice golfers moved their club significantly faster than the expert golfers(p<0.001). Novice golfers could not control the club head effectively, and could not hit the ball correctly. Based on the impact zone movement, sweet spot of novice golfers moved faster(along the line of putt), higher(along the vertical line), and wider(along the side to side line) than that of expert golfers.