• Physical Therapy Korea
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• v.9 no.4
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• pp.45-52
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• 2002

이 연구의 목적은 수직착지시 성에 따른 슬관절 가동범위의 차이를 알아보는 것이다. 연구 대상자는 20대의 건강한 성인 48명(남자 25명, 여자 23명)이었다. 연구 대상자에게 40 cm 높이에서 한발로 뛰어내리도록 하고, 2차원 동작측정 기구인 CMS-HS를 이용하여 수직착지시 슬관절의 굴곡각도, 최대 슬관절 굴곡각도, 슬관절의 가동 범위, 각속도를 측정한 후, 남 여 두 집단간의 차이를 알아보았다. 이때 사용한 분석방법은 독립적인 두 표본 t-검정이었으며 축차적(stepwise) 다변량회귀분석을 이용하여 체중과 신장을 조절한 상태에서 남여 간에 차이가 있는지를 분석하였다. 그 결과 수직착지시 슬관절의 굴곡각도에서는 유의한 차이를 보이지 않았으나, 최대 슬관절 굴곡각도, 슬관절의 가동 범위, 각속도에는 유의한 차이가 있었다(p<.05). 체중과 신장이 조절된 조건 하에서 여자는 수직착지시 최대 슬관절의 굴곡각도와 슬관절의 가동범위가 남자보다 작았다. 이러한 결과를 통하여 수직착지시 여자가 남자보다 슬관절 손상의 빈도가 높은 이유 중의 하나는 여자가 슬관절을 덜 굴곡시킴으로 인해 바닥의 충격을 더 많이 받기 때문이라는 가능성을 발견하였다.

• Physical Therapy Korea
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• v.9 no.4
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• pp.37-44
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• 2002

이 연구의 목적은 발목에 테이핑을 한 후 40 cm의 높이에서 한 발로 수직착지를 할 때 발목관절에서의 테이핑 효과를 분석하는 것이었다. 대상자는 20대의 건강한 성인 14명(남자 4명, 여자 10명) 이었다. 대상자에게 적용한 조건은 테이핑 전, 테이핑 적용, 30분 동안 트레드밀에서 걷기, 테이핑 제거상태 이었고 맥리플렉스(MacReflex)를 이용하여 발끝이 지면에 닿은 상태에서 발목이 최대 배측굴곡(dorsiflexion) 되기까지 걸린 시간, 발목관절 각도변화, 각속도를 측정한 후 반복측정에 의한 분산분석으로 비교하였다. 그 결과 네 개의 조건간에는 통계학적으로 유의한 차이가 없었다(p>.05). 따라서 발목 테이핑은 수직착지시 발목의 배측굴곡을 제한하는 효과는 없다고 판단된다.

• Physical Therapy Korea
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• v.8 no.4
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• pp.17-29
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• 2001

발목에 대한 유착성 테이핑의 적용은 물리치료 분야와 운동 트레이닝 분야에서의 일반적인 치료 접근 방법이라 할 수 있다. 즉 발목 염좌 같은 손상을 예방하기 위한 방법과 재활의 부가적인 치료 형태로 이용될 수 있는 것이다. 본 연구는 발목의 테이핑과 트레드밀에서의 30분간 보행이 수직 착지 동작 동안 하지의 운동 역학적 요소들에 어떠한 영향을 주는지 알아보기 위해 시행되었다. 14명의 신체 건강한 대상자들 (남:10, 여:4)이 본 연구에 참여하였다. 한발로 서있는 동안 40 cm의 높이로 뛰게 하였다. 가자미근, 전경골근, 안쪽넓은근, 넙다리 두갈래근에 근전도 전극이 부착되었다. 테이핑된 신체 부위로 착지하는 동안 근전도와 힘판(force plate) 자료가 500 Hz의 주파수로 수집되었다. 대상자들의 우세쪽 하지 발목에 테이핑을 하였고, 대상자는 한발로 뛰어 내리는 동작을 반복하였다. 트레드밀에서 30분 동안 발목에 테이핑을 한 채로 보행하였고 이후 한발로 뛰어 내리는 동작을 반복하여 수행하였다. 테이핑을 적용한 상태와 테이핑한 채로 30분 동안 트레드밀에서 걷기 운동을 한 조건에서 수직 지면 반발력의 통계학적으로 유의미한 증가가 있었다. 착지 동안에 네 가지 상황에서의 최대 내측 가속도의 유의한 차이가 있었고, 그 차이는 테이핑 전과 테이핑을 한 채로의 운동 조건에서 유의한 차이가 있었다. 테이핑한 상태에서 가자미근은 접촉되는 착지 순간부터 최대 수직 지면 반발력이 나타나는 동안의 평균 근전도의 수치에 있어서 유의한 감소가 있었다. 반면에 다른 근육들에서는 아무런 변화를 보이지 않았다. 비록 발목 테이핑이 발목 손상의 위험을 줄이는데 효과적이라고 일반적으로 인식되고 있으나 이번 실험의 결과는 30분 동안의 트레드밀에서의 보행 후 테이핑은 발목의 움직임을 제한하는 효과는 있지만 한편으로는 가자미근의 활동을 감소시키는 것을 보여주었다. 따라서 이 연구의 결과는 테이핑을 하면 점프와 착지로 이어지는 동작 중에 발목관절 손상 위험을 증가시킬 가능성이 있음을 보여주었다.

• Korean Journal of Applied Biomechanics
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• v.18 no.1
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• pp.107-115
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• 2008

The purpose of this study was to investigate muscle activity and vertical ground reaction force(F) in children with Down syndrome(DS) during vertical jump. Six DS and one healthy child performed vertical jump. Four muscles(Biceps femoris, Rectus femoris, Tibialis anterior & Gastrocnemius) and F were analyzed. Gastrocnemius in DS showed lower muscle activity in a propulsive phase. Impulse during 0.3sec before toe-off in DS displayed lower value than that in the healthy child. The second peak of F in DS occurred later than that in the healthy child, so DS performed landing with their knee more flexed. The first and second peak of F and loading rate to the second peak of F in DS showed lower value than those in the healthy child. Therefore, DS might have lower ability to absorb the force while landing from a vertical jump.

• Journal of the Korean Applied Science and Technology
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• v.36 no.2
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• pp.424-433
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• 2019

The purpose of this study was to investigate the effects of gender difference in injury experience on biomechanical variables of lower extremity during two leg drop landing. 20 male(injury experience=8, non-injury experience=12) and 20 female(injury experience=11, non-Injury Experience=9) in their 20's were selected as subjects. Two-way mixed ANOVA was performed on the biomechanical variables obtained from the two leg drop landing in a 45cm height box and post-test was performed with bonferroni adjustment(p <.05). The results of this study suggest that the group of female who injury experience could induce the reduction of the peak vertical ground reaction force by increasing the valgus and internal rotation of the knee joint and flexion and internal rotation of the hip joint. In the INE(injury non-experienced) female group, the peak knee flexion angle was the smallest, as well as the flexion of the hip joint and the external rotation angle, and the peak vertical ground reaction force was the highest. On the other hand, the INE female group showed high vertical ground reaction force because they did not utilize the knee and hip joints relatively than the IE(injury experienced) female group, this means that it is relatively exposed to the risk of injury. Therefore, it was found that gender difference in injury experience is a factor affecting factors of knee and hip joint movement and peak vertical GRF(ground reaction force).

• Journal of the Korean Applied Science and Technology
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• v.39 no.5
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• pp.701-709
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• 2022

The purpose of this study was to compare the differences according to the visual selection and rotation order during sequential rotational jump for female dancers of a Korean ballet company by classifying them into take-off and landing sections. 10 subjects (age: 26.0±2.9 yrs, height: 163.4±3.3 cm, weight: 46.8±3.6 kg, ballet career: 12.3±5.9 yrs) participated in the study. Using a 3D motion analyzer and a force platform, the height of the body center and the ground reaction force during take-off and landing were measured. According to the visual condition (using both eyes, using left eye, using right eye) and rotation order (first rotation, second rotation), it was analyzed through repeated measurement two-way analysis. Height of the CM was higher in the first jump. In take-off, Fx was lateral force of left foot and medial force of right foot were strong in second rotation, and Fy was forward force was strong in first rotation of right foot. Fz was no significant. In landing, Fy showed backward force was strong when landing the second time from the left foot, and the backward force was strong when using the left sight from the right foot. Fz was strong on the second landing on the left foot and the first landing on the right foot.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.3
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• pp.115-121
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• 2021

Human's landing strategies have been explained through lower extremity kinetics in various conditions. However, how lower extremity kinetics respond when the two conditions between a load and landing height are combined is not yet understood. To achieve the purpose of this study, a total of 20 men and women were subjected to drop landing according to a load(No load, 10%, 20%, 30% of the body weight) at various landing heights(0.3 m, 0.4 m, 0.5 m). As a result of the study, the main effect of a load was not statistically significant in all variables. But increasing of the landing heights showed more flexion angle which was statistically significant in knee joint. In addition, as the landing height increased, the medial-lateral, anterior-posterior, vertical force, and loading rate increased, while time to peak vertical force decreased which was statistically significant. Thus, humans can successfully perform the landing motion even if the load is changed at various heights. However, it reacted more sensitively to the change in landing height than that load condition. The landing height can be prepared for recognition and shock absorption through visual information, but the weight level is difficult for the body to perceive and explains why it is more difficult to apply it to the landing strategy mechanism for shock absorption.

• Korean Journal of Applied Biomechanics
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• v.19 no.1
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• pp.87-98
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• 2009

This study was conducted to compare biomechanical differences in throwing movement between skilled and unskilled high school students using three-dimensional analysis system with a force platform. The findings indicated that skilled students showed shorter throwing time, faster horizontal speed of (1) the center of mass at heel contact of left foot, (2) the forearm throughout swing phase, (3) the hand after heel contact while unskilled students showed faster horizontal speed of, (1) the center of mass after heel contact and (2) the hand at heel contact of left foot. Skilled students showed greater (1) shoulder angle during throwing, (2) elbow angle after take off of foot, (3) peak vertical ground reaction force during throwing and (4) peak anterior-posterior ground reaction force at heel contact of right foot. While skilled students showed leaning backward of the trunk during throwing, unskilled students showed leaning forward during release phase with leaning backward before release.

• Korean Journal of Applied Biomechanics
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• v.19 no.4
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• pp.707-717
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• 2009

The purpose of this study was to investigate the kinematic parameters between a stalled group and a less skilled group of female javelin throwers, in order to record differences in their support landing and release phase. For this, the female athletes were divided into two groups: the sidled group, which consisted of javelin throwers with records over 45m, and the less skilled group, which consisted of javelin throwers with records below 45m. During the release phase, the horizontal velocity differed significantly(p<.05) between the two groups. The projection angle at the release moment also differed significantly(p<05) between the groups. The knee angle of the support leg differed significantly(p<.05) between the two groups at E1, E2, and E3, but there was no difference at E4. The shoulder angle differed significantly(p<.05) between the two groups only during the landing of the power leg.

• Korean Journal of Applied Biomechanics
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• v.18 no.1
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• pp.129-135
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• 2008

This research was examined the effect of Backward Walk on ground reaction force and we achieved it by using ground reaction force machine during the Backward Walk activity with Latin and Rumba dance. We find that it was significant difference of vertical(Fz) ground reaction force of right foot in touchdown and toe-off and vertical(Fz), horizontal(Fx), front-rear(Fy) ground reaction force of left foot. There was not significant differences in vertical ground reaction force between superior athlete and unskilled athlete, but there was a significant difference in left foot. Through this, we know that the sports capability of left foot which has been developed through the training is better in superior athlete group. Therefore understanding of difference in ground reaction force and repeated training can help the unskilled athlete and beginner to accomplish the accurate movement.