• The Journal of Korean Physical Therapy
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• 제27권5호
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• pp.315-319
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• 2015

Purpose: The purpose of this study was to investigate the effect of leg-crossing positions on muscle activities of rectus femoris, tensor fascia latae, and hamstring in healthy 20's adults. Methods: Twenty healthy subjects were asked to perform three leg-crossing positions, leg crossing (LC), tailor crossing (TC), and ankle crossing (AC). Surface electromyography (EMG) was used to evaluate the activities of rectus femoris, tensor fascia latae, and hamstring during upright sit posture (UP) and three leg-crossing positions and UP was compared to three leg-crossing positions. Repeated one way ANOVA was used for data analysis. The alpha level was set at 0.05. Results: The results showed significant difference in the muscle activities of rectus femoris, tensor fascia latae, and hamstring among leg-crossing positions. The muscle activity of the rectus femoris was significantly lower in LC and TC positions than UP. The muscle activity of tensor fascia latae was significantly higher in LC position than UP and other leg-crossing positions. The muscle activity of hamstring was significantly higher in LC and TC positions and significantly lower in AC position than in UP. Conclusion: Our study suggests that the activity of hip muscles was affected by pelvic and knee alignment in various leg-crossing positions.

• The Journal of Korean Physical Therapy
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• 제19권5호
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• pp.1-10
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• 2007

Purpose: Leg-crossing sitting is very common for men and woman. No solid evidence exists for either a beneficial or a detrimental effect of this posture. This study investigated the change of activities of trunk muscles between the normal group and the low back pain group during various leg-crossing positions. Methods: The subjects were consisted of 10 subjects who don't have low back pain and 10 subjects who have low back pain. In this study, we used electromyography(EMG) to evaluate the activities of both the trunk muscles (rectus abdominis, external oblique, internal oblique, and multifidus) during various leg-crossing positions (up-right, leg-crossing, tailor-crossing, and ankle-crossing). We analyzed the data by using repeated one way ANOVA. Results: In normal group, there were increased in EMG activities of trunk muscles, but no significant differences during leg-crossing positions. In back pain group, there were increased in EMG activities of right external oblique, left. internal oblique, and both multifidus muscles in leg-crossing and tailor-crossing position, but no significant differences during leg-crossing positions. There was no significant difference of muscle activity of trunk muscles between the back pain group and the normal group. Conclusion: We suggest that low back pain people who have weak muscles of rectus abdominis, external and internal oblique are often experienced in leg-crossing posture than normal. To compensate this unstability of trunk, leg-crossing posture is substituted passive structure for activities of active muscle.

• 근관절건강학회지
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• 제22권3호
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• pp.160-166
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• 2015

Purpose: The purpose of this study is to examine the effect of leg crossing on reducing orthostatic hypotension and orthostatic hypotension symptoms in hemodialysis patients. Methods: A one-group pretest-posttest design was used. A total of 40 post-hemodialysis adult patients were enrolled, excluding the case of intradialysis hypotension, unbalance of standing with leg crossing, adding antihypertensive medications. Blood pressure (BP) and heart rate (HR) were measured in supine and standing positions. After a week, BP and HR were measured in supine and standing with leg crossing position. Orthostatic hypotension symptoms were also measured by self-reported structured questionnaire in standing without leg crossing and with leg crossing position. Results: We found out that systolic blood pressure, diastolic blood pressure, and mean arterial pressure increased significantly in standing with crossing leg position applied (p=.006, p=.001, p=.006). However, presences of orthostatic hypotension symptoms were not significantly decreased in standing with leg crossing position (p=.500, p=.318, p=.306, p=.241, p=.356, p=.500, p=.241, p=.308). Conclusion: This study shows that leg crossing is effective for reducing orthostatic hypotension without additional cost or instruments. Leg crossing as one of the preventive interventions to reduce orthostatic hypotension is easier and simpler to be implemented in hemodialysis patients.

• 한국전문물리치료학회지
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• 제15권4호
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• pp.80-86
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• 2008

Cross-legged sitting postures are commonly assumed during computer work. The purpose of this study was to determine the effects of leg crossing on trunk muscle activity while typing at a computer. Trunk muscle activity was measured in three 8 different sitting postures, in random order. These posture were: normal sitting with a straight trunk and both feet on the floor (NS), upper leg crossing (ULC), and ankle on knee (AOK). The right leg was crossed onto the left leg in both cross-legged postures. Twenty able-bodied male volunteers participated in this study. Subjects typed on a computer keyboard for one minute. Surface electromyography (EMG) was used to record bilateral muscle activity in the external oblique (EO). internal oblique (IO), and rectus abdominis (RA). The EMG activity of each muscle in the NS posture was used as a reference (100% EMG activity) in relation to the two cross-legged postures. Muscle activity in the right EO. right IO, and left IO was significantly lower in the ULC posture than in the NS posture. In contrast, muscle activity in the right RA was significantly higher in the ULC posture than in the NS posture. Muscle activity in the tight RA was significantly higher in the AOK posture, as compared to the NS posture, whereas activity in the left IO was significantly lower in the AOK posture, as compared to the NS posture. The right-left muscle activity ratios in the EO and IO showed significantly different patterns in the cross-legged postures, suggesting that asymmetrical right-left oblique muscle activity had occurred.

• 한국콘텐츠학회논문지
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• 제15권12호
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• pp.370-377
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• 2015

본 연구는 282명의 노인을 대상으로 근육뼈대계 통증이 횡단보도 보행에 미치는 영향을 알아보고자 실시되었다. 연구방법은 근골격계 증상 조사표를 이용하여 노인의 근육뼈대계 통증을 조사한 후 4, 6차선 횡단보도를 보행하도록 하여 보행속도, 보행시간, 걸음수를 측정하였다. 연구결과 신체부위별 근육뼈대계 통증은 허리통증의 호소율이 가장 높았고(33.3%), 허리와 다리/발에 근육뼈대계 통증이 있을 경우 보행속도는 감소하고 걸음수와 보행시간이 증가하는 특징을 보였지만, 지팡이 사용이 횡단보도 보행에 도움을 줄 수 있는 것으로 나타났다. 하지만 허리와 다리/발의 통증정도는 횡단보도 보행특성 사이에 통계적으로 유의한 연관성을 확인할 수 없었다. 이후 지속적인 연구를 통해 노인의 다양한 신체적 문제들과 횡단보도 보행에 관한 연구들이 이루어지길 바란다.

• 대한물리의학회지
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• 제14권4호
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• pp.55-62
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• 2019

PURPOSE: This study examined the muscle activity while stepping over obstacles with various heights and widths to provide basic data for training and preventing falls. METHODS: Fifteen normal young adults (seven males and eight females) were recruited. The participants walked on a 5m walkway with six obstacles. The heights of obstacles were 0%, 10%, and 40% of the subject's leg length, and the width of the obstacles was 7cm and 14cm. The participants traversed the course twice per obstacle. The muscle activities of the soleus, tibialis anterior (TA), vastus medialis (VM), and vastus lateralis (VL) were measured using surface electromyography. A Mann-Whitney test and Kruskal-Wallis test were used to examine the differences between obstacles. RESULTS: The muscle activities of the VL and the soleus of the stance leg and lead leg after crossing over the obstacles increased with increasing width, and there were significant differences in muscle activities between obstacle width (p<.05) except for the muscle activity of TA of the stance leg after crossing over the obstacles. A significant difference in muscle activities was observed according to the height of the obstacles with 14 cm (p<.05) except for the muscle activity of the VL, soleus of the leading leg, and TA of the stance leg CONCLUSION: The role of the VL and Soleus increased with increasing obstacle width, and the overall muscle activities of the lower extremities increased with increasing obstacle height. These results can be used to suggest a program to prevent falls.

• 한국해양공학회지
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• 제5권1호
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• pp.16-24
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• 1991

This paper presents a method of the reliability analysis for a tension leg platform(TLP)in severe storm waves by using the first passage concept of the random tensile stress in the tendons. In the present method, two failure conditions are considered ;i.e., the exceedance of the ultimate tensile capacity and the occurrence of the negative tension. In order to consider the correlation effects between the failure events for each corner resulted from the rupture of all tencons at one corner, a new system limit state for a rectangular shaped TLP is developed, which is defined in terms of the TLP motions in the vertical plane ;i.e., heave, roll, and pitch. To illustrate the validity of the present method, the numerical analysis is carried out for two TLP's with different structural dimensions. Then, the results are compared with those by other methods.

• 한국컴퓨터그래픽스학회논문지
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• 제23권2호
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• pp.23-27
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• 2017

본 논문에서는 기존에 발표되었던 데이터 기반보행제어 기법의 단점을 보완하는 다리 간 충돌 회피 기법을 제안한다. 2010년에 제안된 Lee et. al. 의 데이터 기반 이족 보행 제어 기법 [1]은 경우에 따라 보행 중 두 다리가 서로 교차하는 동작을 만들어내기도 하는데, 이는 실제 사람 혹은 이족 보행 로봇의 보행에서는 실현될 수 없는 동작이다. 본 논문에서는 스윙 힙(swing hip)의 각도를 변경하는 피드백 규칙에 스탠스 레그 (stance leg)와의 충돌을 피할 수 있는 추가적인 각도조절을 도입하여 스윙 풋 (swing foot)이 스탠스 풋 (stance foot)을 지난 이후에만 스탠스 풋보다 안쪽으로 움직일 수 있도록 하는 알고리즘을 제안한다. 이를 통해 기존의 제어기 동작 방식에 최소한의 변경과 추가적인 계산만을 더하여 두 다리가 교차하지 않는 안정적인 보행 결과를 만들어 낼 수 있다.

• 근관절건강학회지
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• 제19권1호
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• pp.27-36
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• 2012

Purpose: The purpose of this study was to investigate the leg length Inequality, habitual posture, and pain in women's college students. Methods: The subjects were 281 students, in 8 women's college in Korea. The tapelines were used for measuring leg length Inequality and questionnaires were used for measuring habitual posture, and pain. The data were collected between August and October 2010 and analyzed using SPSSWIN 11.5. length Inequality(<1 cm). The subjects of 2.8% were the length differences of above 2cm. The worst habitual posture were leaning habits. Especially, the habits of crossing her legs were significantly different to leg length Inequality(F=3.342, $p$=.037). The subjects of 84% were felt a severe pain on the upper body such as waist, back, scapula, neck or shoulder. But there is no difference between pain and leg length Inequality. Habitual posture are related to pain(r=.212, $p$=.001). Conclusion: To protect the severe health problem of musculoskeletal system, this study results will be give aid to health education in women's college students.

• 한국정밀공학회지
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• 제13권11호
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• pp.152-162
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• 1996

A four-legged Walking Machine can move on the plain terrain with mobility and stability and stability, but if there exist any obstacles on the terrain of the motion direction, it takes extra time to cross those obstacles and the stability should be considered during motion. The main objective is the study a Quadruped which can cross obstacles with better mobility, stability and fuel economy than any other wheeled or tracked vehicles. Vertical step, isolated wall and ditch are the basic obstacles and by understanding those three cases perfectly, a Quadruped can move on any mixed rough terrain as 4-legged terrestrial vertebrates move. Each leg of a Quadruped has a limited walk space called a walking volume and this is very important to deter- mine the crossing capability in a static analysis. A Quadruped can be simplified with links and joints. By applying the research method, a quadruped can determine the control procedures as soon as it receives the terrain information from scanner and finally can move with mobility and stability.