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

• Journal of Digital Convergence
• /
• v.14 no.11
• /
• pp.645-654
• /
• 2016

The purpose of this research is aimed at billiards experts and non-experts during the billiard stroke: a comparative analysis of concentration and muscle activity, identifying the differences between the two groups by the objective and scientific data is presented to propose the basis for effective and efficient training methods of billiards. The results of the study showed no significant differences in muscle activity and concentration between experts and non-experts. Therefore, the muscle activity and concentration between the experts and non-experts had no positive effect during the billiard stroke. These causes are thought to be as a lack of research subjects, being a one-time experiment, and not being able to control psychological and physiological experiments completely. In this regard, psychological and physiological experiments are considered to be controlled for further study to determine the principles more clearly.

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

• Restorative Dentistry and Endodontics
• /
• v.28 no.2
• /
• pp.146-155
• /
• 2003

여러 가지 장점으로 인해 Ni-Ti 전동 파일을 근관성형에 사용하는 빈도가 점차 증가되는 추세이지만, 초심자를 대상으로 한 연구는 부족한 실정이다. 이에 본 연구에서는 초심자에서 Ni-Ti 전동 파일을 사용할 때 근관 형성의 효용성을 평가하고, 어떤 방법이 초심자에게 적절한지를 알아보고자 하였다. 근관형태가 재현된 레진 블록을 이용하여 12명의 초심자와 4명의 숙련자가 근관 형성을 시행하였다. 각 술자는 ProFile, ProTaper, Hybrid (ProFile＋ProTaper)를 이용하여 각각의 레진 블록을 세 개씩 근관형성하고, 각 파일 별의 근관 형성 시간을 기록하였다. 근관 형성 전과 후의 digital 이미지를 중첩하여 치근단으로부터 1, 2, 3, 4, 5, 6, 7mm level에서 근관단면의 총길이 변화량, 만곡 외측의 길이 변화량, 만곡 내측의 길이 변화량, 중심이동량, 중심이동율과 치근단에서의 apical transportation을 구하고, 초심자와 숙련자 사이의 차이를 비교 평가하였다. 실험결과 ProFile군의 1, 3, 5, 6, 7mm level과 ProTaper군의 6mm level, Hybrid군의 3mm level에서 초심자의 근관단면의 총길이 변화량이 숙련자보다 많았다. 모든 군에서 치근단으로부터 4, 5, 6, 7mm level에서는 근관 중심이 만곡내측으로 이동하였고, 1 2, 3mm level 에서는 만곡외측으로 이동하였으나, 숙련자가 시행한 Hybrid군의 3mm level과 비숙련자가 시행한 ProTaper 군의 3mm level에서는 만곡내측으로 이동하였다. 모든 군의 3mm level과 ProFile 군의 5mm level에서 초심자의 중심이동율이 숙련자에 비해 컸으며, 초심자가 ProTaper를 사용시 더 큰 apical trans portation을 보였고, 모든 군에서 초심자가 근관형성시 더 많은 시간이 걸렸다. ProFile과 ProTaper를 이용한 Hybrid technique이 초심자에게 추천되며, 초심자들도 충분히 교육받는다면 만곡된 근관의 근관형성에 있어서 Ni-Ti rotary file의 이용이 가능하리라고 사료된다.

• Journal of Labour Economics
• /
• v.21 no.1
• /
• pp.1-30
• /
• 1998

• Journal of Labour Economics
• /
• v.16
• /
• pp.131-172
• /
• 1993

• The Journal of Korean Institute for Practical Engineering Education
• /
• v.3 no.1
• /
• pp.200-205
• /
• 2011

This research is first to analyze an electomygram reaction of the lower limbs among the muscles used during a back-round kicking of Taekwondo, second to analyze the relationship between the muscles of the kicking limb and those of the supporting limb, third to compare EMG activity of expert with novice. Measured muscles are as follows; rectus fermoris which control flexion and stretching of femora and knee joints, vastus medialis and vastus lateralis, which control flexion and stretching of legs, and biceps fermoris, which control stretching of femora, bending of knee joints and abduction of the crus. The electomygram reaction of all these selected muscles were analyzed. Three kicks were performed, and electomygram of each of kicks were measured. Then, electomygram reaction of the best kick was used for electomygram analysis.

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2007.11a
• /
• pp.105-106
• /
• 2007

• Korean Journal of Applied Biomechanics
• /
• v.12 no.2
• /
• pp.207-214
• /
• 2002

The purpose of this study was to examine 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(1/500 shutter speed). The results showed that the angle of the clubface of expert golfers was almost 1 degree, but the novice golfers were more than 6 degrees. Expert golfers moved their hands faster than the head movement, therefore the clubface was not opened during impact. However, the novice golfers moved their hands slower than the head movement, therefore the clubface was opened during impact. The ratio of input and output angles of total movement was 1:3-4, however, the ratio of input and output angles of impact zone was 1:2. The angle of normal vector of expert golfers was less than the angle of normal vector of novice golfers.

• The Journal of Information Systems
• /
• v.25 no.3
• /
• pp.91-116
• /
• 2016

Purpose Quality and quantity of knowledge in virtual communities is at the discretion of knowledge contributors, and understanding what motivates knowledge contributors' behavior can be invaluable. The purpose of this paper is to find the social aspect of knowledge contribution in virtual communities within the frame of self-determination theory. Also, we seek differential effects of motivation value for novice vs. expert knowledge contributors. Design/methodology/approach Reputation and altruistic motives are studied as antecedents of intrinsic and extrinsic values in contributing knowledge in virtual communities. Gained social connectedness and satisfaction in their knowledge were behaviors studied as dependents of the motivational value. Also, the proposed model was tested for group differences between expert and novice knowledge contributors seeking motivational changes. Self-determination theory is the base theory which explains how externally motivated behaviors can evolve from extrinsically motivated to intrinsic-like behavior with social experiences as knowledge contributors. Findings Analysis of 262 data points gathered from knowledge contributors in Korean virtual communities in 2005 reveals social connectedness as an important dependent variable both for novice and expert knowledge contributors. Group difference analysis shows altruism has negative influence on extrinsic value only for experts. Intrinsic value has a positive influence on satisfaction for both groups alike but the expert group shows a statistically stronger influence than the other.