• Korean Journal of Applied Biomechanics
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• v.18 no.2
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• pp.19-27
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• 2008

The purpose of this study was to investigate of assessment of the ability of balance control using COP 95% confidence ellipse area while executing single-leg stance with eyes open and eyes closed through GRF system. The subjects participated in this study were 7 female yoga group and 7 female control group. The yoga training affected to improve the ability of balance control because the yoga group's COP AP and ML standard deviation and COP 95% confidence ellipse area were smaller than control group in both a single-leg stance with eyes open and eyes closed. Visual affected to the ability of balance control in a single-leg stance. I consider COP 95% confidence ellipse area as a high variable for determining the ability of balance control, and therefore suggest that additional studies for various groups and subjects will be required in the future.

• 한국체육학회지인문사회과학편
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• v.58 no.6
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• pp.449-459
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• 2019

The purpose of this study is to identify how postural mechanics affects postural control on balance and stability by using frequency analysis technique from the kinematic data acquired during the one leg standing posture. For this purpose, the experimental group consisted of two groups, the normal group (n=6) and the national Gymnastics group (n=6). Displacement data of CoP were analyzed by frequency analysis of rambling (RM) and trembling (TR) by FFT signal processing. As a results, there was a significant difference in evaluating the stabilization index between the two groups with the eyes open and closed one leg stnading (p <.05). The cause of the difference was found to be the output of the maximum amplitude of RM (f1) and TR (f2) (p <.05). In particular, in the low frequency RM of 8-9 Hz, which is a natural frequency of signal wave involved in postural feedback feedback, the main frequency appeared to be performs the exercise mechanism of stable brain posture control. And in the high frequency TM of 120-135 Hz, it is considered that the adaptation of the reflective muscle response is minimized to minimize posture shaking. In conclusion, this study provides evidence for the intrinsic main frequencies according to the postural control ability which affects the CNS in one leg standing.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.11
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• pp.1323-1329
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• 2011

The purpose of study was to analyze how the visual information affects balance control of individuals during single leg stance. A total of 27 young normal people (20 males and 7 females, age: $13.7{\pm}2.6$, height: $162.3{\pm}13.2$ cm, weight: $53.9{\pm}13.9$ kg) was voluntarily involved in the experiment. The subjects were requested to maintain balance for 20 seconds with eyes both open and closed on a force plate and then foot ground reaction data were collected for that duration. Results showed that mean velocity of COP in closed eyes condition was larger 1.84 times than that of the open-eyes condition and range of vertical angle was increased approximately one degree in the closed eyes condition. To accomplish a balance, the frequency power in mediolateral and anteroposterior components of the foot-ground reaction force was increased by 1.3~1.4 times. Consequently, visual absence during single leg stance can result in critical loss of balance and lead to instability of body control.

• 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.

• Journal of Dental Rehabilitation and Applied Science
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• v.29 no.1
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• pp.1-9
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• 2013

This study examined the effects of the occlusal stability and a partial coverage mouthguard on physical fitness and motor capacity to determine the importance of the occlusal stability as a possible action mechanism of mouthguards on physical performance. Twenty physical education students were included for measurements of their handgrip strength, back strength, whole body reaction time, flexibility, sidestep test, stork stand test and jumping test according to the following 5 different occlusal conditions: mouth closed position without a mouthguard, with a full coverage mouthguard, with a right partial coverage mouthguard, with a left partial coverage mouthguard and with anterior partial mouthguard. The results revealed no significant difference in any of the measured physical factors between the occlusal conditions with and without a full-coverage mouthguard. On the other hand, a significant difference was observed in whole body reaction between the occlusal conditions with and without the partial coverage mouthguards. Therefore, isokinetic muscle tests on both knee joints and the Wingate anaerobic power test should be performed under the following five occlusal conditions: with or without full-coverage maxillary custom-made mouthguard, with a unilateral right or left partial-coverage maxillary mouthguard and with an anterior partial-coverage maxillary mouthguard. These results suggest that the partial coverage mouthguard had a short-term beneficial effect on agility rather than full coverage mouthguard.

• The Journal of the Korea Contents Association
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• v.8 no.10
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• pp.251-258
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• 2008

This study was to investigate the effects of the combined patterns of PNF(proprioceptive neuromuscular facilitation) on the static balance ability by 20 subjects for 6 weeks. The combined patterns of PNF were carried out by Sprinter and Skater suggested by Dietz which were practiced once a day, 3 times a week. This study were measured normal standing, one leg left and one leg right standing when eye open and close on GOOD BALANCE system. These result lead us to the conclusion that mean velocity of X,Y direction, COP velocity moment were showed a statically decrease applying post-exercise on Normal Standing Eye Open(NSEO), Normal Standing Eye Close(NSEC), One Leg Right Standing Eye Close(OLRSEC) and Just velocity of X direction were showed a statically decrease applying post-exercise on One Leg Right Standing Eye Close(OLRSEC). The above results from this study indicated that combined patterns of PNF have improved the static balance ability. However the used self-exercise ca be applied to normal people, i.e., the exercise is difficult to apply into clinical patients. The further study should be focused at development of various modified forms of the combined patterns of PNF in keeping up the improvement effect of the exercise.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.1113-1115
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• 2014

본 프로젝트팀에서 개발한 'VTK'(Virtual Training by Kinect)는 아이부터 노인까지 모든 연령이 이용 가능한 기능성 게임으로써 동작인식 컨트롤러인 키넥트를 이용하여 불필요한 장비가 없이 동작인식을 통해 인터페이스가 가능하게 했다. 주요기능은 평가와 트레이닝, 통계분석 세 가지로 이루어져 있다. 사용자는 6분 걷기와 폐안시 외발서기를 통해 개인별 심폐지구력과 평형감각 수준을 알 수 있으며 조깅과 인라인 스케이트를 통해 기능 향상을 위한 트레이닝을 할 수 있다. 통계분석은 별도의 용용프로그램을 통해 확인 할 수 있다. 성장하고 있는 기능성 게임 시장에 새로운 방향성 제시를 목표로 하였다.

• Korean Journal of Applied Biomechanics
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• v.22 no.2
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• pp.219-228
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• 2012

The purpose of this study was to investigate how induced fatigue of the ankle joint muscles affects the capability and recovery of postural control during single-leg stance in healthy adults. The study population included 22 randomly recruited men and women. Postural control was performed on single-leg stance with eyes open. Ankle joint muscle was fatigued by repeated heel raises. According to the results of this study, for the anteroposterior variables, both men and women showed significantly increased center of mass velocity and decreased center of pressure 95% edge frequency immediately after fatigue. For the mediolateral variables, both men and women showed significantly increased center of mass velocity and decreased center of pressure 95% edge frequency immediately after fatigue. For the total variables, both men and women showed significantly increased center of mass averaged-velocity immediately after fatigue, and also, the center of pressure 95% confidence ellipse area significantly increased in women. Postural control variables were not significantly different for men and women at any time (Pre, P0, P10, and P20). In conclusion, the gender does not affect the capability and recovery after induced fatigue of ankle joint muscles. The effect of fatigue found for the anteroposterior and the mediolateral variables in both men and women. Furthermore ankle joint muscle fatigue led to change of postural control strategy from an ankle joint strategy towards a hip joint strategy. These changes are believed to damage postural control. The ankle joint muscle recovered from fatigue within 20 min during single-leg stance.

• Korean Journal of Applied Biomechanics
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• v.23 no.4
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• pp.335-345
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• 2013

The purpose of this study was to investigate the effects of foot type and ankle joint fatigue levels on the trajectories of center of pressure and center of mass during a single-leg stance. The study subjects included 24 healthy women (normal foot group, n=10; pronated foot group, n=14). Ankle joint muscle fatigue was induced by using an isokinetic dynamometer, where the fatigue levels were measured on plantar flexion and dorsiflexion at angular velocities of $30^{\circ}/s$ at 50% and 30% of the peak torque of ankle plantar flexion. Following assessments in the anteroposterior direction according to the level of fatigue, the pronated foot group showed decreased single-leg stance ability at 50% and 30% of the fatigue level. Moreover, the normal foot group showed better single-leg stance ability than the pronated foot group at 30% of the fatigue level. Following assessments in the mediolateral direction, we noted that the single-leg stance ability did not differ significantly according to the levels of fatigue or foot type. In conclusion, ankle plantar flexion at 50% and 30% of the peak torque reduced the ability of the pronated foot group to achieve a single leg stance in the anteroposterior direction. Moreover, the normal foot group showed better single-leg stance ability than the pronated foot group.

• Journal of the Korean Society of Physical Medicine
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• v.8 no.2
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• pp.201-207
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• 2013

연구목적: 닌텐도 위를 이용한 가상현실기반 비디오게임 프로그램을 만성기 뇌졸중 환자에게 적용하여 균형능력 및 일상생활동작에 어떠한 영향을 미치는지 알아보고, 뇌졸중 환자의 재활프로그램으로서 적용 가능성이 있는지 알아보고자 한다. 연구방법: 만성기 뇌졸중 환자를 무작위로 가상현실기반 비디오게임 프로그램을 적용한 실험군(n=7)과 적용하지 않은 대조군(n=10)으로 구분하여 연구를 진행하였다. 연구에 참여한 모든 대상자에게 30분의 Bobath therapy와 15분간의 FES 치료를 기본적으로 실시하였다. 이에 더하여 실험군은 가상현실기반 비디오게임 프로그램을 1일 30분이내, 주 5회, 3주간 실시하였다. 대조군은 자전거 운동과 보행훈련으로 30분간 시행하였다. 실험 전 후 눈뜨고 외발서기(OLST; open leg standing test), Timed Up and Go(TUG) 검사, 10m 걷기 검사, Functional Independence Measure(FIM)를 측정하였다. 실험 전과 실험 후 측정값의 차이를 비교하기 위해 Wilcoxon Signed Ranks Test를 실시하였다. 그리고 각 측정값의 변화량에 대한 실험군과 대조군 사이의 차이를 알아보기 위해 Mann-Whitney U Test를 실시하였다. 연구결과: 실험결과는 다음과 같다. 1) 실험군에서는 FIM의 유의한 증가와 TUG, 10m 걷기 검사의 유의한 감소를(p<.05) 보였다. 대조군에서는 OLST의 증가와 TUG, 10m walking test의 감소가 나타났지만 통계적으로 유의하지 않았다. 오직 FIM에서만 유의한 증가가 나타났다(p<.05). 2) 실험 전 후의 실험군과 대조군의 각 측정값들의 평균차를 비교한 결과 실험군은 대조군보다 실험 전 후 OLST, TUG, 10m walking test 차이의 평균은 컸지만 통계적으로 유의하지 않았다. 결론: 이상의 결과로부터 가상현실기반 비디오게임이 만성기 뇌졸중 환자의 동적균형능력 및 일상생활동작 향상에 효과가 있음을 알 수 있었다.