• 제목/요약/키워드: COP(center of pressure)

검색결과 200건 처리시간 0.025초

히트펌프 직렬운전에 의한 성능 향상 가능성에 관한 연구 (Potential Performance Enhancement of Dual Heat Pump Systems through Series Operation)

  • 백영진;김민성;장기창;이영수;김현주
    • 대한기계학회논문집B
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    • 제36권8호
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    • pp.797-802
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    • 2012
  • 본 연구에서는 두 대의 히트펌프를 이용하여 $60^{\circ}C$의 난방 공급을 하는 경우에 대하여, 병렬운전을 할 경우의 성능과 직렬운전을 할 경우의 성능을 서로 비교함으로써, 직렬운전에 의한 성능 향상 가능성을 연구하였다. 두 경우의 성능을 공정하게 비교하기 위하여, 히트펌프를 구성하는 열교환기의 전열면적을 고정하였으며, 부하측 및 열원측의 입구 유량 및 온도 조건을 고정하였다. 또한, 보다 현실적인 결과를 위하여 열교환기 내 열전달 및 압력강하 특성을 고려하였다. 시뮬레이션 결과, 직렬운전 시스템의 난방성능계수가 병렬운전 시스템의 난방성능계수에 비해 본 연구의 시뮬레이션 조건 하에서 약 5% 향상 될 수 있음을 관찰하였다.

보행 시 지지 기반 급변에 대한 하지 근신경의 반응 (Leg Muscle Activity from the Perturbation of the Support during Gait)

  • 신인식;천영진;서정석;최치선;남기정
    • 한국운동역학회지
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    • 제17권3호
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    • pp.147-154
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    • 2007
  • This study's purpose is to investigate the effects on leg muscle activity caused by perturbation, using a trapdoor system during the support phase of gait for healthy adults (n = 6, height $177.5{\pm}5.5cm$, weight $81.0{\pm}9.5kg$, age $30.0{\pm}3.3yrs$). The trapdoor had the functional ability of causing inversion or eversion. The release time for the trapdoor was specified for two times, 0.3 and 0.5 seconds after heel contact. While altering these variables, EMG was recorded for the leg muscles (rectus femoris, biceps femoris, vastus lateralis, tibialis anterior, gastrocnemius, soleus). The following conclusions were derived. The steptime was longer for the 0.5s eversion than 0.3s inversion condition. So in order to regain stability after the perturbation the unsupporting leg reached forward rapidly. This quick reflex can be observed through the center of pressure (COP) and its rapid change in direction. The gastrocnemius was activated throughout the total experiment. There was a low amount of activity recorded in the rectus femoris, vastus lateralis and tibialis anterior except for the condition of inversion 0.3s. For most of the conditions, the highest average EMG peak values were recorded during the condition of inversion 0.3s. The iEMG patterns were similar for the conditions of inversion 0.3s and eversion 0.3s. To cope with the rapid change in these conditions, the biceps femoris was activated. During the experiment except for the condition of normal gait, the activity of the soleus and gastrocnemius was relatively high. Therefore, to prevent injury from perturbation of the lower leg strengthening of the soleus and gastrocnemius is required. Likewise to prevent injury to the thigh strengthening for the biceps femoris.

컴파운드 양궁의 팔로우 스루 동작과 사격 정확도의 상관관계 (Relationship of Follow-through Movements to Target Accuracy in Compound Archers)

  • Junkyung Song;Kitae Kim
    • 한국운동역학회지
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    • 제34권1호
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    • pp.34-44
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    • 2024
  • Objective: This study aimed to investigate how the movements occurring during the follow-through phase after releasing an arrow among elite compound archers, are associated with the arrow impact points on the target. Method: Nine elite archers performed consecutive compound archery shooting under conditions identical to actual competitions using their own bows and equipment. Motion capture system and force platform were utilized to record the changes in joint positions and center of pressure, respectively. Principal component analysis was employed to identify the patterns in which multidimensional joint positions and COP changes were organized with horizontal and vertical coordinates of arrow impact points. Subsequently, correlation analysis quantified the relationship between individual variables and the coordinates of arrow impacts on the target. Results: We found a common organizational pattern in which the two axes of the impact point coordinates were grouped into the first two principal components. The movements of the upper and lower limbs following release exhibited opposite patterns in the anterior-posterior axis, with significant correlations observed between the arrow impact points of the horizontal axis and the left shoulder, right elbow, left hip, and both knees. Additionally, the lateral movements induced by the reaction force upon arrow release showed significant associations with the vertical coordinates of the impact points. Particularly, the correlations between the movements of the left shoulder and elbow, as well as the bilateral hip and right knee, were consistently observed among all participants. Conclusion: These findings implied that the post-release movements could significantly influence the trajectory and impact points of the arrows in compound archery. We suggest that a consistent and controlled movement during the follow-through phase may be more beneficial for optimizing shooting accuracy and precision rather than minimizing movements.

배호흡운동을 동반한 닫힌 사슬 하지운동이 뇌졸중 환자의 체간조절 및 균형에 미치는 영향 (Effects of Closed Chain Lower Limb Exercise with Abdomial Breathing Exercise on Trunk Control and Balance in Stroke Patients)

  • 이제혁;김성호
    • 대한치료과학회지
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    • 제10권2호
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    • pp.31-37
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    • 2018
  • Objective: The purpose of this study was to evaluate the effects of closed chain lower limb exercise with abdominal breathing exercise on stroke patients and their effects on trunk control ability and balance. Method: The subjects were 40 stroke patients, 19 patients in the experimental group and 18 patients in the control group. The period was 5 weeks, 5 times a week, 30 minutes per session. The experimental group was subjected to a closed chain lower limb exercise with abdominal breathing exercise and the control group was subjected to a closed chain lower limb exercise. The posture assessment scale for stroke(PASS), trunk impairment scale(TIS) were used for trunk adjustment ability, and the balance ability was measured as center of pressure(COP) and limit of stability(LOS). Results: Results of this study showed that the PASS and TIS test significantly increased the experimental group compared to the control group. As a result of comparing the changes of pre and post intervention intervals between the two groups, the TIS test was significantly lower in the experimental group than in the control group, but the LOS test was not significantly increased in the experimental group. Conclusion: Closed chain lower limb exercise with abdominal breathing exercise showed a significant improvement in the trunk control and balance ability of the stroke patients compared to the closed chain lower limb exercise without the abdominal breathing exercise.

Effect of Treadmill Training with Ankle Joint Taping on Gait Function and Balance Ability in Patients with Subacute Stroke: A Randomized, Controlled, Preliminary Trial

  • Gill, Yeong-Jin;Oh, Se-Jung;Cha, Yong-Jun
    • 대한물리의학회지
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    • 제17권1호
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    • pp.21-30
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    • 2022
  • PURPOSE: This study examined the effects of treadmill training with taping on the affected ankle joint on the gait and balancing ability in patients with sub-acute stroke. METHODS: Nineteen patients with sub-acute hemiplegic stroke in a rehabilitation hospital were assigned randomly to either the experimental group (n = 10), who received treadmill training with taping on the affected ankle joint or the control group (n = 9), who received general treadmill training. All participants performed 60 min of comprehensive rehabilitation therapy (five sessions per week for four weeks). Each group received treadmill training with or without taping on the affected ankle joint for 20 min (three sessions per week for four weeks). The gait and balancing ability were measured before and after the four-week training. RESULTS: Post-training scores of 10-meter walk test (10 MWT), timed up and go (TUG) test, and center of pressure (COP) path length and velocity for the experimental group increased significantly compared to that pre-training (p < .05). The experimental group showed a larger decrease in the 10 MWT and TUG test than the control group (-3.5 s vs. -1.01 s, p < .05; -4.9 s vs. -1.7 s, p < .05; respectively) CONCLUSION: Treadmill training with taping on the affected ankle joint might improve the gait and balancing ability of stroke patients and is considered a more effective method for improving gait and balancing ability than the method of general treadmill training.

하지 허혈 유발에 따른 선형 운동 역치 변화 (Effect of Lower Limb Ischemia on Linear Motion Perception)

  • 이용우;박수경
    • 대한기계학회논문집B
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    • 제35권11호
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    • pp.1185-1190
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    • 2011
  • 말초 신경 병변 환자들에게 하지 체성감각의 저하는 균형 능력 저하와 관련이 있다. 일반적으로 균형 능력은 운동 결과를 측정하여 평가하여 왔다. 그러나 인체 움직임은 다양한 감각 신호들이 통합된 운동지각에 의해 유발된다. 따라서, 본 연구에서는 하지 체성감각의 저하는 운동 지각 능력 또한 저하시킬 것이라는 가정하에, 이를 확인하기 위하여 허혈에 의한 하지 체성 감각 저하를 유도하였고, 이때의 피부감각 민감도 및 선형 운동 방향 지각 능력의 변화를 측정 하였다. 이 결과 발바닥 체성감각 저하 유도시에는 운동 지각 역시 저하되었다. 그러나 운동 결과에 해당하는 압력 중심은 변화하지 않았다. 따라서, 운동 지각 측정이 체성 감각 저하를 조기 발견할 수 있는 평가 방법으로 사용될 수 있음을 확인하였다.

기능적 전기자극을 병행한 거울치료가 만성 뇌졸중 환자의 균형 및 보행능력에 미치는 영향에 관한 융합적 연구 (A Convergence Study on the Effects of functional electrical stimulation with mirror therapy on balance and gait ability in chronic stroke patients.)

  • 김동훈;김경훈
    • 한국융합학회논문지
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    • 제9권10호
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    • pp.109-120
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    • 2018
  • 본 연구의 목적은 기능적 전기자극을 병행한 거울치료가 만성 뇌졸중 환자의 균형과 보행능력에 미치는 영향을 알아보기 위함이다. 선정기준에 따라 만성 뇌졸중 환자를 35명을 대상으로 세군으로 실시하였다. FMT군은 기능적 전기자극을 병행한 거울치료(n=11), MT군은 거울치료를 시행하였고(n=12), CON군(n=12)은 일반적인 물리치료를 시행하였다. 훈련은 1일 30분, 1주 5번, 총 4주간 시행하였다. 중재 전 훈련 4주 후에 균형과 보행능력을 검사실시하였다. 훈련결과 기능적 전기자극을 병행한 거울치료 훈련군이 버그균형척도, 신체의 이동거리, 활보장, 분속수, 그리고 평균보행속도에서는 거울치료군과 대조군에 비해 통계학적으로 유의한 차이를 보였다. 그러므로 기능적 전기자극 치료와 거울치료 융합은 뇌졸중 환자의 균형과 보행능력을 위한 효과적인 중재로 활용 될 수 있으며, 다양한 뇌졸중 환자를 위한 지속적인 융합중재개발이 요구된다.

슬링 요부안정화 운동프로그램이 청소년기 특발성 척추측만증 환자의 균형에 미치는 영향 (Effect of Sling Lmubar Stabilization Exercise Program on the Balance of Adolescent Idiopathic Scoliosis Patients)

  • 배영현;박선희;이혜림;이석민
    • 한국산학기술학회논문지
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    • 제13권7호
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    • pp.3074-3084
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    • 2012
  • 본 연구의 목적은 청소년기 특발성 척추측만증 환자를 대상으로 슬링을 이용한 요부안정화 운동프로그램이 정적 선 자세의 균형에 미치는 영향을 알아보고자 하였다. 본 연구의 대상자는 특발성 척추측만증을 진단 받은 환자 40명을 무작위로 두군으로 나눈 후 실험군(n=20)은 슬링 요부안정화 운동, 대조군(n=20)은 단지 자세교육만 실시하였다. 두군 모두 실험 전 후 균형 수행 모니터(Balance performance monitor)을 이용하여 눈을 감은 상태에서의 양발서기 자세와 눈을 뜬 상태에서의 양발서기에서 동요거리(총, 좌우방향, 전후방향)와 동요속도(총, 좌우방향, 전후방향)를 측정하였다. 운동프로그램 적용 후에 두그룹간에 모든 변수에서 유의한 차이를 보였다. 실험군은 운동 전 후 모든 변수에서 유의한 감소를 보였다. 그러나 대조군에서는 유의한 차이를 보이지 않았다. 이상의 결과를 통해서 슬링 요부안정화 운동프로그램은 특발성 척추측만증 환자의 체중심 동요거리와 동요속도를 감소시켜 정적 선 자세 균형능력을 향상시켰으며 슬링 요부안정화 운동프로그램이 청소년기 특발성 척추측만증 환자의 균형 증진 중재가 될 수 있을 것으로 보인다.

Kinematic Characteristics Based on Proficiency In Geoduepyeopchagi in Taekwondo Poomsae Koryo

  • So, Jae Moo;Kang, Sung-Sun;Hong, AhReum;Jung, Jong Min;Kim, Jai Jeong
    • 한국운동역학회지
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    • 제26권4호
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    • pp.343-351
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    • 2016
  • Objective: The purpose of this study was to help improve game performance and provide preliminary data to enhance the efficiency of the kick and stability of the support foot by comparing the kinematic characteristics of the repeated side kick (geodeupyeopchagi) in poomsaeKoryo between expert and non-expert groups. Method: The subjects were divided into 2 groups according to proficiency in Taekwondo, an expert group and a non-expert group (n = 7 in each group), to observe the repeated side-kick technique. Four video cameras were set at a speed of 60 frames/sec and exposure time of 1/500 sec to measure the kinematic factors of the 2 groups. The Kwon3D XPprogramas used to collect and analyze three-dimensional spatial coordinates. Ground reaction force data were obtained through a force plate with a 1.200-Hz frequency. An independent samplesttest was performed, and statistical significance was defined as .05. The SPSS 18.0 software was used to calculate the mean and standard deviation of the kinematic factors and to identify the difference between the experts and non-experts. Results: The angular displacement of the hip joint in both the expert and non-expert groups showed statistical significance on E1 and E4 of the left support foot and E5 of the right foot (p<.05). The angle displacement of the knee joint in both groups showed statistical significance on E4 of the left support foot, and E1 and E2 of the right foot (p<.05). The angular velocity of the lower leg in both groups showed no statistical significance on the left support foot but showed statistical significance on E2 and E6 of the right foot (p<.05). The angular velocity of the foot in both groups showed no statistical significance on the left support foot but showed statistical significance on E2 of the right foot (p<.05). The vertical ground reaction force in both groups showed statistical significance on E2 (p<.05). The center of pressure in all directions in both groups showed statistical significance (p<.5). Conclusion: While performing the repeated side kick (geodeupyeopchagi), the experts maintainedconsistency and stability of the angle of the support leg while the kick foot moved high and fast. On the other hand, the angle of the support foot of non-experts appeared inconsistent, and the kick foot was raised, relying on the support leg, resulting in unstable and inaccurate movement.

라이프케어 증진을 위한 협응적 이동훈련 프로그램이 비만 여성노인의 균형에 미치는 영향 (The Effects of Coordinative Locomotor Training Program for Life-Care Promotion on Balance of Obese Elderly Women)

  • 이동률
    • 한국엔터테인먼트산업학회논문지
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    • 제14권1호
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    • pp.17-25
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    • 2020
  • 본 연구는 라이프케어 증진을 위한 협응적 이동훈련 프로그램이 비만 여성노인의 균형에 미치는 영향을 알아보았다. 본 연구의 대상자는 비만 여성노인 10명으로, 최근 1년 이내 허리나 엉덩관절 및 무릎관절 수술경험이 없고 독립보행이 가능한 자로 선정하였다. 협응적 이동훈련을 일일30분씩 2회, 주5회, 4주간 총 20회 실시하였다. 협응적 이동훈련 프로그램의 효과를 알아보기 위해 인바디 BMI검사, myoVIDEO를 이용한 관절가동범위검사, 표면근전도 검사(척추세움근, 배바깥빗근, 넙다리네갈래근, 넙다리뒤근육), 힘판 트레드밀을 통한 동적 균형검사, 버그 균형 척도(BBS)와 일어서서 걷기 검사(TUG)를 중재전후 시행하였다. 본 연구의 연구결과, 보행 시 디딤기 및 흔듦기 시기에 몸통과 엉덩관절의 관절가동범위 전-후 비교에서 통계학적으로 유의한 차이가 있었으며(p<0.05), 표면근전도를 통한 근 활성도검사에서는 척추세움근과 배바깥빗근의 중재 전-후 비교에서 통계학적으로 유의한 차이가 있었다(p<0.05). 보행 시 동적균형검사에서는 보행선길이와 한발지지선의 중재 전-후 비교에서 유의한 차이가 있었으며(p<0.05), 버그 균형 척도(BBS)와 일어서서 걷기검사(TUG)에서도 중재 전-후 비교에서 유의한 차이가 있었다(p<0.05). 본 연구결과를 통해 라이프케어 증진을 위한 협응적 이동훈련 프로그램이 비만 여성노인의 자세불안정과 근 약화, 균형능력감소 및 낙상위험도를 개선에 유의한 영향을 주는 것을 알 수 있었다. 따라서 비만 여성노인의 균형능력 개선 및 낙상방지를 통한 라이프케어증진을 위해 이동적 협응훈련 프로그램 적용을 권장한다.