• Korean Journal of Applied Biomechanics
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• v.16 no.3
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• pp.19-31
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• 2006

이 연구의 목적은 각 분절의 마커세트와 무릎관절 중심 정의가 3차원 무릎 관절각을 산출하는데 얼마나 민감하게 영향을 미치는지를 연구하였다. 자료수집은 1명을 실험대상자로 하여 두 가지 형태의 각기 다른 분절의 정의와 무릎관절의 중심을 나타내는 반사마커들을 동시에 오른쪽 하지에 부착시켜 실험을 실시하였다. 실험대상자의 달리기동작 중 좌측으로 45도 방향전환동작의 지지기를 분석하였다. 이를 위해서 8대의 고속카메라들을 이용하였고 달리기속도는 4m/$sec{\pm}(10%)$로 통제하였다. 하지분절의 발분절에는 하나의 마커세트를, 정강이와 대퇴분절에는 두 가지의 다른 마커세트들을 부착시켰다. 발분절에는 3개의 마커를 신발의 뒷부분에 부착하였고 정강이분절을 정의하기 위하여 첫 번째 마커세트는 경골을 중심으로 3개의 마커들을 두 번째 마커세트는 비골을 중심으로 3개의 마커를 부착하였다. 대퇴분절의 마커세트를 정의하기 위하여 첫 번째 마커세트에는 대퇴골을 중심으로 3개의 마커를 두 번째 마커세트에는 대퇴근육을 중심으로 3개의 마커들을 부착하였다. 무릎관절중심을 정의하는데 두 가지 다른 정의가 적용되었다. 첫 번째 무릎중심을 무릎의 내측과 외측의 마커들을 통해 두 마커의 중심을 무릎관절의 중심으로 정의하였다. 두 번째 무릎중심정의는 무릎의 외측부분과 슬개골의 중심에 부착된 마커들로부터의 교차점을 무릎관절중심으로 산출하였다. 무릎관절의 각도를 산출하기 위해서 JCS(Joint Coordinate System)의 정의가 적용되었고 연구의 결과는 다음과 같았다. 두 가지의 다른 분절마커세트 사이에서 무릎의 신전(extension)과 굴곡(flexion)은 유사한 형태를 나타냈으며 최대 무릎굴곡(peak knee flexion)각에서 $4.746^{\circ}$의 차이를 나타냈다. 다른 분절마커세트 사이의 회전(rotation)각과 내전(adduction)/외전(abduction)에서는 서로 다른 형태를 나타내었고, 두 마커세트간 최대무릎외측회전(peak knee external rotation)각도에서는 $15.628^{\circ}$의 차이를 나타냈다. 또한, 각 분절마커세트 내에서 두 가지의 다른 무릎관절 중심의 정의가 얼마나 무릎도 산출에 영향을 미치는지를 비교했을 때 무릎의 최대외측회전(peak external rotation)각에서 차이를 나타내었다. 첫 번째 분절마커세트의 무릎관절중심정의의 형태변화에 따라 최대외측회전각은 $0.549^{\circ}$의 차이를 나타냈고, 두 번째 분절마커 세트에서 무릎관절중심정의의 형태변화에 따라 최대외측회전각은 $0.309^{\circ}$의 차이를 나타냈다. 이와 같이 분절을 나타내는 마커세트와 무릎관절중심정의의 형태변화에 따라 무릎간을 계산하는데 있어서 결과가 다르게 산출되었다. 즉, 관절각의 계산이 분절에 부착되는 마커의 정의 혹은 위치에 매우 민감하게 영향을 받았다. 따라서 연구자가 여러 실험대상자들을 대상으로 실험시 마커세트 혹은 마커들을 동일한 위치에 가깝게 부착하는 것이 마커부착으로부터 발생하는 실험오차를 줄일 수 있을 것이다.

• Journal of Korea Entertainment Industry Association
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• v.14 no.8
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• pp.337-344
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• 2020

The purpose of this study was to investigate the effect of theratainment low extremity complex exercise using unstable surface on knee and static plantar pressure in patient with genu varum. 25 adult subjects were recruited and randomized into stable surface exercise group(SEG) and unstable surface exercise group(UEG). Subjects carried out complex exercise(elastic band exercise & squat exercise) for 40 minutes, 4 times per week for 5 weeks. The knee joint distance and Q-angle of all subjects measured, the foot pressure measured distribution on the front and rear of both foots during pre and post. The most outcome at post was significantly improved than the pre outcome in the both group(p<.05). The result of this study show that the low extremity complex exercise using unstable surface may be appropriate for improving structure of knee joint and static plantar pressure in patient with genu varum. This will enable the application of low extremity complex exercise using unstable surface in rehabilitation therapy of genu varum and it will help guide the selection of the therapist as one therapeutic basis.

• Proceedings of the Korean Society of Computer Information Conference
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• 2021.07a
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• pp.311-312
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• 2021

본 연구는 실내외 자전거 운동 시 빈번히 발생하고 있는 무릎상해를 예방하기 위해 자전거 운동을 실시할 때 올바른 자세를 유지 할 수 있도록 도와주는 보호 장비 개발 내용이다. 자전거 운동 시 발생할 수 있는 손상을 예방하기 위해서는 안장의 높이, 좌우 무릎사이의 간격, 무릎 각도가 안전한 각도 범위내에 있어야 한다. 본 연구에서는 이러한 무릎의 올바른 정렬을 유지한 채 운동을 지속할 수 있도록 센서부와 제어기로 구성되는 것을 특징으로 한다. 센서부는 가속도 센서, 자이로 센서, 속도감지 센서로 구성하여 자전거 운동 시 정상적인 무릎정렬과 비교하여 올바르지 못한 정렬 상태에서 운동 시 즉시 피드백하여 자세를 수정할 수 있도록 유도해 무릎의 상해를 예방하는 실내외 자전거 이용 시 운동 상해를 예방하기 위한 무릎 보호대를 개발하고자 한다.

• Journal of the Korea Convergence Society
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• v.7 no.2
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• pp.43-52
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• 2016

The purpose of this study was to suggest the effective squat exercise position to strengthening vastus medialis oblique, and vastus lateralis in quadriceps. Subjects were twenty patients with patellofemoral pain syndrome (PFPS) volunteered to participate in this study. All subjects were applied to static squat convergence exercise with knee flexed $45^{\circ}$, $60^{\circ}$, and $90^{\circ}$ for 30 seconds total 5 times. Measurement variables were maximal voluntary isometric contraction (MVIC) of the quadriceps, Q angle and length of thigh. Those were measured before and after the squat exercise on knee joint angle, change rate of which were used for statistical analysis. As a result, squat exercise with knee flexed $90^{\circ}$ increase significantly among knee joint angle in the MVIC change rates of quadriceps (p<.05), however the rates of Q-angle and length change of thigh showed no significant difference. Therefore, this findings suggest that squat exercise with knee flexed $90^{\circ}$ strengthen quadriceps effectively in patients with PFPS.

• Journal of Life Science
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• v.16 no.5
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• pp.773-779
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• 2006

Eight of the individuals had a unilateral S-RAD TKA and Multi-Radius TKA ($Scorpio^{TM}$ PS, Howmedica-Osteonics, Inc.). The instrument were used Peak Motion Measurement $System^{TM}$, $MYOPAC^{TM}$EMG System, KIN-COM $III^{TM}$ System. The Figure 3 shows that the average time for the S-RAD group to accomplish the sit-to-stand movement was 1.59 s, which was 0.19 s less than the M-RAD group (p= 0.033). In Figure 5, the S-RAD TKA group tended to have $7^{\Omega}{\cdot}S^{-1}$ less trunk flexion velocity than that of the M-RAD group (p= 0.058). The Figure 6 shows that the S-RAD TKA limb tended to have less ADD displacement (p = 0.071) than that of the M-RAD TKA limb. We failed to find significant differences for ABD and ADD displacements between the S-RAD and M-RAD N-TKA limbs (p= 0.128 and 0.457, respectively). The VM of the S-RAD TKA limb demonstrated significant less RMS EMG than that of the M-RAD TKA limb from $60^{\Omega}$ to $15^{\Omega}$ of knee flexion (p 0.05). The VL of the S-RAD TKA limb also demonstrated significant less RMS EMG than that of the M-RAD TKA limb from $60^{\Omega}$ to $45^{\Omega}$ of knee flexion (p 0.05). Similar to the VM and VL, the RF of the S-RAD TKA limb showed less RMS EMG than that of the M-RAD TKA limb from $60^{\Omega}$ to $30^{\Omega}$ of knee flexion (p 0.05).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1445-1446
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• 2011

• Journal of Digital Convergence
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• v.12 no.9
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• pp.407-415
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• 2014

The purpose of this study is to identify the relation between isokinetic strength of knee extensors and angular velocity of knee joint during fente motion in elite fencers by three disciplines and gender, and to provide the preliminary data for developing the training program and rehabilitation program to enhance sports-performance by three disciplines and gender. Total 31 elite fencers who trained at the national training center of the Korean Olympic Committee (KOC) participated in this study.; 10 fleuret (4 males), 10 epee (6 males) and 11 sabre (5 males). Subjects were measured eccentric and concentric isokinetic strength (PT/BW, WK/BW) of the knee extensors at angular velocity of $60^{\circ}/s$, $180^{\circ}/s$ and $300^{\circ}/s$, and flexion (P1) and extension (P2) angular velocity of knee joint during fente motion. To examine the relationship between isokinetic strength of knee extensor and angular velocity of knee motion, Pearson's correlation coefficient (r). ${\alpha}=.05$ was considered significant. In conclusion, the relationship of isokinetic strength of knee extensors and angular velocity of knee was different depending on three disciplines and gender.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.422-428
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• 2018

This study was conducted to investigate the effects of trunk stability exercise on knee function, balance and gait in patients who underwent total knee arthroplasty. The subjects of this study were recruited from individuals diagnosed with degenerative arthritis who had undergone total knee arthroplasty. Overall, 24 patients were randomly divided into a control groups and an experimental groups (12 each). The trunk stability exercise was conducted for 4 weeks with three exercises developed in a previous study. The measurement tools used were knee function measurements based on the Lysholm knee score, balance ability measured using a test of TUG and OLS, and a walking ability test measured using a 10MWT. Pre and post test results were within groups were compared using the paired t-test, whole differences between groups were compared using the independent t-test. The experimental group showed significantly enhanced results relative to the control group (p<0.05). Based on these results, trunk stability exercise in parallel with knee joint therapy effectively improves the recovery of patients with total knee arthroplasty.

• Korean Journal of Applied Biomechanics
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• v.18 no.1
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• pp.21-30
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• 2008

The purpose of this study was to investigate the variability to compare local dynamic stability via a linear and nonlinear analysis during walking. Twenty four elderly males, 12 healthy elderly and 12 patients with osteoarthritise walked on a treadmill for 100 consecutive strides. Lyapunov exponent and correlation dimension and coefficient variation were calculated for the kinematic parameters to determine the dynamic stability during walking. The linear measures indicated that the healthy elderly demonstrated significantly higher variability in the ankle joint displacement. The nonlinear analysis revealed that COD for the knee joint angle were higher in patient with osteoarthritise. There were no coincidence in results between linear and nonlinear techniques over two groups. In light of nonlinear analysis, it was concluded that patients with osteoathritise showed higher local instability during walking.

• Journal of the Korea Convergence Society
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• v.10 no.9
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• pp.63-68
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• 2019

The purpose of this study was to investigate the effect of hyper-extended knee and asymmetric standing posture on knee joint position and lower extremity muscle activity. Thirty-three voluntary participants participated and included sixty legs in the study. The sixty legs were divided into two groups: hyper-extended knee and normal group. The muscle activity and knee extension angle were measured. In the asymmetric standing posture, the knee joint extension angle and the muscle activity of the gastrocnemius were statistically significant between the normal group and the hyper-extended knee group. Based on the results, we confirmed that the asymmetric standing posture increases the hyper-extended knee. Therefore, it will contribute to the establishment of therapeutic guide for the subjects with hyper-extended knee to maintain the symmetrical standing posture, and future studies need to be conducted including the effects of the hip joint and ankle joints.