• 대한물리의학회지
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• 제18권4호
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• pp.89-96
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• 2023

PURPOSE: To investigate the effects of the underwater Ai-Chi exercise on the joint range of motion, balance and posture. METHODS: Thirty-six college students (30 men, 6 women) were divided into a 'low physical activity' groups (Group I). and an 'appropriate physical activity' groups (Group II). The Ai-Chi underwater exercise was conducted three times a week for two weeks for both groups. A goniometer was used to measure the range of motion of the hip joint, and Y-Balance and the posture screen mobile were used to measure the stability of the lower extremities. RESULTS: An evaluation of the range of motion of the hip joint before and after the Ai-Chi exercise showed significant results in the low physical activity group. However, the flexural range showed a significant increase after exercise, but not significant result. In the comparison of the mean increase between groups, only the right hip joint showed a significant difference in both groups. Also, in the comparison of the Y balance test and posture screen test before and after exercise, both groups showed significant. CONCLUSION: The Ai-Chi underwater exercise helped improve the range of motion of the hip joint and the ability to balance. Also It helped improve posture alignment. In addition, although the increase in all physical activity groups lower than the appropriate physical activity groups was greater in all figures, the increase in the number of samples, the extension of the experimental period, and various variables could be obtained.

• 한국운동역학회지
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• 제17권4호
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• pp.27-36
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• 2007

The purpose of this study was to investigate the effect of the upper body in order to increase a propulsive force in the old's walking. The subjects were each 10 males, the latter term of the aged and former term of the aged. There were three walking speeds of slow(about 5km/h), medium(about 6km/h), and maximum speed(about 7km/h). The subjects walking 11m were filmed the 5m section (from 3m to 8m) by 2-video cameras using three dimensional cinematography. And we computed different mechanical quantities and especially computed the relative momentum in order to achieve this study's aim. In this study, we was able to acquire some knowledge. The step length and step frequency increased in proportion to the walking speed, and the faster walking speed, the shorter ratio of supporting time( both legs supporting time/one step length time). When it was one leg support phase, the torso was indicated to generate the momentum in order to produce the propulsive force of walking. The upper and lower body had a cooperative relation for walking such as keeping step rate with the arms to legs and maintaining the body balance. The opposition phase for upward-and-downward direction of the torso and arms in walking was functioned to prevent the increase rapidly toward vertical direction of the center of gravity. The arms had contributed to coordinate the tempo of legs and the posture maintenance of the upper body. And by absorbing the relative momentum from the upper torso with arms to the lower torso, it had the rhythmical movement on upward-and-downward direction reducing the vertical reaction force. On account of the relations of absorption and generation of the propulsive force and the production of vertical impulse in the lower torso when walking by maximum speed, it was showed that the function of lower torso was come up as important problem for the mechanical posture stability and propulsive force coordination.

• 제어로봇시스템학회논문지
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• 제20권1호
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• pp.87-93
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• 2014

Conventional two-wheeled balancing robots are limited in terms of turning speed because they lack the lateral motion to compensate for the centrifugal force needed to stop rollover. In order to improve lateral stability, this paper suggests a two-wheeled balancing mobile platform equipped with a tilting mechanism to generate roll motions. In terms of static force analysis, it is shown that the two-body sliding type tilting method is more suitable for small-size mobile robots than the single-body type. For the mathematical modeling, the tilting-balancing platform is assumed as a 3D inverted pendulum and the four-degrees-of-freedom equation of motion is derived. In the velocity/posture control loop, the desired tilting angle is naturally determined according to the changes of forward velocity and steering yaw rate. The efficiency of the developed tilting type balancing mobile platform is validated through experimental results.

• 한국안광학회지
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• 제19권2호
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• pp.239-246
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• 2014

목적: 정적자세에서 유도된 비정시가 신체균형에 미치는 영향을 알아보았다. 방법: 평균 연령 $23.4{pm}2.70$세의 20명(남 10, 여 10)을 대상으로 ${pm}0.50D$, ${\pm}1.00D$, ${\pm}1.50D$, ${\pm}2.00D$, ${\pm}3.00D$, ${\pm}4.00D$, ${\pm}5.00D$의 렌즈를 사용하여 비정시(양안근시, 단순근시성부동시, 양안원시, 단순원시성부동시)를 유도하였다. TETRAX the biofeedback system을 이용하여 신체안정성지수, 체중분포지수, 낙상지수를 측정하였다. 신체균형 검사는 각 조건 당 32초간 측정되었고, 반복측정 후 완전교정상태에서 측정한 값과 비교하였다. 결과: 안정성지수는 양안근시의 경우 +0.50 D부터, 단순근시성부동시의 경우 +1.00 D부터, 양안원시의 경우 -1.00 D부터, 단순원시성부동시의 경우 -1.50 D부터 완전교정상태와 비교하여 유의하게 증가되었다. 낙상지수는 양안근시의 경우 +4.00 D부터, 양안원시의 경우 -1.00 D부터, 단순원시성부동시의 경우 -1.50 D부터 유의하게 증가되었다. 모든 비정시 유형에서 체중분포지수의 변화는 없었다. 결론: 비정시의 유형에 상관없이 굴절이상의 미교정은 신체균형의 전반적인 안정성을 감소시키고, 낙상의 위험도를 증가시킬 수 있다.

• 한국멀티미디어학회논문지
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• 제3권4호
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• pp.389-398
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• 2000

본 연구에서는 PDS시스템 -HMD와 기타 VDU-이 가상환경에서 인체에 어떠한 영향을 미치는가를 조사하였다. 연구에 관련된 실험은 HMD나 VDU를 착용하고 한시간 정도의 3차원 게임을 한 결과를 분석하였다. 정량적인 측정 및 분석 도구로는 SSQ와 RSSQ, 실험전후의 자세 테스트, 그리고 시각 테스트가 실행되었다. 실험 결과는 피 실험자간의 개인적 차이는 있지만 자세 안정성 테스트 결과와 SSQ 와 RSSQ TS 간의 관계가 크다는 것을 알 수 있었다. HMD의 SSQ, RSSQ 의 TS는 VDU의 TS 보다 1.5배 높았고, 특히 넓은 시야를 가진 MRG 3C의 TS는 SS를 일으킬 가능성이 2배나 많았다. 시뮬레이터의 통제 정도에 따른 Sickness 정도를 조사하기 위하여 수동적 환경과 능동적 환경에서 실험한 결과 PDS간 유의성은 보이지 않았으며 같은 환경의 반복적인 경험을 통하여 sickness유발 가능성이 감소할 것이라는 가정도 유의성이 크지 않았다. 방향감각 상실 증상군과 안구운동 불편 증상군의 TS가 높게 나타났으며 또한 RSSQ를 통하여 긴장/당황증상군의 TS도 높게 나타났다. 이는 가상환경에 노출시 개인적 두려움도 sickness 가능성을 유발하고 있다고 유추할 수 있었다.

• 대한의용생체공학회:의공학회지
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• 제28권5호
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• pp.628-635
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• 2007

We studied the effect of vibratory stimulations of different leg muscles, tibialis anterior(TA) and triceps surae(TS), and plantar zones in ten healthy subjects during 1) quiet standing, 2) forward lean of body, 3) backward lean of body, 4) right lean of body, and 5) left lean of body. The experiments were performed on the force platform. The effect of vibration were measured by monitoring the area of COP(Center of pressure) sway. The subjects wore a vibratory stimulation system on foot and ankles and were given the instruction not to resist against the applied perturbations. The results show that all vibratory stimulations to lower limb muscles and plantar zones reduced the COP sway area. This reduction of the COP sway area occurred also in partial vibratory stimulations during quiet standing. In forward lean of body, vibratory stimulations to TA reduced the COP sway area. During backward lean of body, vibratory stimulations to TS reduced the COP sway area. When the subject was tilted right, vibratory stimulations to left plantar zone reduced the COP sway area. During left lean of body, vibratory stimulations to right plantar zone reduced the COP sway area. Thus, the influence of vibratory stimulations to leg muscle and plantar zones differed significantly depending on the lean of body. We suggest that the vibration stimuli from leg muscles and plantar zones could be selectively used to help maintaining postural balance stable.

• International journal of advanced smart convergence
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• 제3권1호
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• pp.20-24
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• 2014

To compare body signal, was designed the F-B function system on the body movement for the comfortable state. To detect subject of the normal state, was decided on the base of physical signal in the body movement. There are to detect the condition of Vision, Vestibular, Somatosensory and CNS. Vision condition was verified a variation of greater average (Vi-${\Phi}_{AVG-AVG}$) was presented slightly greater at $17.424{\pm}9.65$ unit. Vestibular condition was identified a variation of slightly greater average (Ve-${\Phi}_{AVG-AVG}$) was presented at $9.068{\pm}1.478$ unit. Somatosensory condition was checked a variation of smaller average (So-${\Phi}_{AVG-AVG}$) was presented slightly smaller at $2.79{\pm}0.419$ unit. CNS condition was confirmed a variation of diminutive smaller average (C-${\Phi}_{AVG-AVG}$) was presented slightly larger at $0.557{\pm}0.153$ unit. As the model depends on the F-B function system of body movement, average values of these perturbation were computed F-B function comparison data. These systems will be to infer a data algorithm and a data signal processing system for the evaluation of the stability.

• 대한정형도수물리치료학회지
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• 제4권1호
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• pp.7-20
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• 1998

Activity of the trunk muscles is essential for maintaining stability of the lumbar spine because of the unstable structure of that portion of the spine. The central nervous system deals with stabilization of the spine by contraction of the abdominal and multifidus muscles in anticipations of reactive forces produced by limb movement. Recent evidence indicates that the lumbar multifidus muscle and transversus abdominis muscle may be involved in controlling spinal stability. Stabilization training in neutral spine is an integrated approach of education in proper posture and body mechanics along with exercise to improve strength, flexibility, muscular and cardiovascular endurance, and coordination of movement.

• 대한정형도수물리치료학회지
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• 제25권1호
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• pp.29-36
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• 2019

Background: This study was conducted to investigate the effect of leg lift difference on the serratus anterior muscle and the upper trapezius muscle when a subject with winged scapula performs a scapula protraction exercise in a four-leg crawling posture. Method: Twenty normal adults and 20 subjects with winged scapula participated in the experiment. Surface EMG recordings were collected from serratus anterior muscle and back trapezius muscle during scapula protraction exercises. Scapular winging is measured with the lifting distance of scapula retraction to the back using an electronic digital caliper. In two groups of four-leg crawling posture, the two legs support, the dominant leg lifting, and the non-dominant leg lifting, including the scapula protraction, were performed. To examine the difference between groups in the variance analysis, the Bonferroni correction was used (significance level ${\alpha}=.017$). Statistical significance level ${\alpha}$ was .05. Results: There was a significant difference in serratus anterior muscle and upper trapezius muscle during push-up plus exercise in leg lifting in four-leg crawling posture, but there were no significant differences in muscle activity between serratus anterior muscle and upper trapezius muscle, and there was no significant difference according to the presence or absence of scapular winging. Conclusion: For the shoulder stability of the ipsilateral side with the serratus anterior muscle, the leg-lifting posture is effective in the four-leg crawling, and also when a subject with winged scapula chooses an exercise, lifting the ipsilateral side of leg with scapula protraction exercises at the same time may have a positive effect on scapula dysfunction.

• International Journal of Internet, Broadcasting and Communication
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• 제13권1호
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• pp.47-53
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• 2021

Gait kinematics and kinetics have a similar tendency between men and women, yet it remains unclear how walking while carrying a load affects the gait mechanism. Twenty adults walked with preferred velocity on level ground of 20 m relative to change of a load carriage (no load, 15%, 30% of the body weights) aimed to observe gait mechanism. We measured gait posture using the three-dimensional image analysis and ground reaction force system during stance phase on left foot. In main effect of gender difference, men showed increased displacement of center of gravity (COG) compared to women, and it showed more extended joint angle of hip and knee in sagittal plane. In main effect of a load difference, knee joint showed more flexed postuel relative to increase of load carriage. In main effect of load difference on the kinetic variables, medial-lateral force, anterior-posterior force (1st breaking, 2nd propulsive), vertical force, center of pressure (COP) area, leg stiffness, and whole body stiffness showed more increased values relative to increase of load carriage. Also, men showed more increased COP area compared to women. Interaction showed in the 1st anterior-posterior force, and as a result of one-way variance analysis, it was found that a load main effect had a greater influence on the increase in the magnitude of the braking force than the gender. The data in this study explains that women require little kinematic alteration compared to men, while men in more stiff posture accommodate an added load compared to women during gait. Additionally, it suggests that dynamic stability is maintained by adopting different gait strategies relative to gender and load difference.