• Journal of Life Science
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• v.14 no.3
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• pp.484-489
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• 2004

Artificial joint replacement is one of the major surgical advances of the 21th century. The primary purpose of a TKA (Total Knee Arthroplasty) is to restore normal knee Auction. Therefore, ideally, a TKA should: (a) maintain the natural leverage of the knee joint muscles to ensure generating adequate knee muscle moments to accomplish daily tasks such as rising from a chair or climbing stairs;(b) allow the same range of motion as an complete knee; and (c) provide adequate knee joint stability. Four individuals (2 peoples after surgery one year and 2 peoples after surgery three years) participated in this study. All they were prescreened for health and functional status by the same surgeon who performed the operations. Two days of accommodation practice occurred prior to the actual strength testing. The isometric strength (KIN-COM III) of the quadriceps and hamstring were measured at 60$^\circ$ and 30$^\circ$ of knee flexion, respectively. During isokinetic concentric testing, the range of motion was between 10$^\circ$ to 80$^\circ$ of knee flexion (stand-to-sit) and extension (sit-to-stand). for a given test, the trial exhibiting maximum torque was analyzed. A 16-channel MYOPACTM EMG system (Run Technologies, Inc.) was used to collect the differential input surface electromyographic (EMG) signals of the vastus medialis (VM), vastus lateralis(VL), rectus femoris (RF) during sit-to-stand and stand-to-sit tests. Disposable electrodes (Blue SensorTM, Medicotest, Inc.) were used to collect the EMG signals. The results were as follows; 1. Less maximum concentric (16% and 21% less for 1 yew man and 3 years mm, respectively) and isometric (12% and 29%, respectively) quadriceps torque for both participants. 2.14% less maximum hamstrings concentric torque for 1 year man but 16% greater torque for 3 years mm. However, 1 year man had similar hamstring isometric peak torque for both knees. 3. Less quadriceps co-contraction by 1 year man except for the VM at 10$^\circ$-20$^\circ$ and 30$^\circ$-50$^\circ$ range of knee flexion.

• Korean Journal of Applied Biomechanics
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• v.18 no.2
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• pp.75-83
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• 2008

The purpose of this study was to evaluate the correlation between joint moment and joint position angle according to the different walking speeds. According to the different walking speeds(1.5m/s, 1.8m/s, 2.1m/s), experiments were terminated by 8 male subjects. In conclusion, 1. The peak extensor moment of knee joint increased by increasing walking speed, however, walking speed didn't have an effect on peak flexor and abductor moment of knee joint. 2. The position angle of knee joint increased movement of flexion, but other position angles of knee joint didn't have difference when the peak extensor moment generated. 3. The peak joint moment of hip significantly increased in extension, flexion and abduction by increased walking speed. 4. The hip position angle showed more flexible at the hip peak flexor/extensor moment generated. 5. The co-ordination pattern between peak knee joint moment and knee position angle were mathematically modeled by using a least square method. We could get the high level value of R2. We expect to apply this results for evaluating the physical faculty of knee joint.

• Korean Journal of Applied Biomechanics
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• v.18 no.3
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• pp.83-92
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• 2008

Y. W. KIM, Y. J. KIM, Mechanical Properties of Unilateral & Bilateral Movements in Isokinetic Knee Extension and Flexion. Korean Journal of Sport Biomechanics, Vol. 18, No. 3, pp. 83-92, 2008. The purpose of this study was to examine the mechanical properties and patterns of bilateral and unilateral movement under varying velocities and movement patterns. The unilateral and bilateral isokinetic knee extension and flexion were taken for three speeds of 13 healthy male subjects. Although there was bilateral facilitation at the speed of $450^{\circ}$/s for the bilateral movement of knee extension, as a whole there was less resultant torque and power of bilateral movement than summed unilateral under knee flexion and extension of 3 velocity condition. There was significant correlations between bilateral deficits within individuals observed for an the same movement($120^{\circ}-240^{\circ}$ flexion, $120-240^{\circ}$ extension, $240^{\circ}-450^{\circ}$ extension), which means that same agonist was recruited. On the contrary, although there was a tendency of a similar pattern of the individuals bilateral deficit according to the varying velocities, there was not a significant correlations between bilateral deficits of flexion and extension within individual, which means that different agonist was recruited. With the analyses of this results the individuals neuromuscular characteristics and the effecting factors for bilateral movement can be speculated upon.

• Korean Journal of Applied Biomechanics
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• v.18 no.4
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• pp.161-169
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• 2008

The purpose of this study was to investigate kinetic variables of the lower extremity during walking on three different stair widths in healthy adults. Ten healthy college-aged adults($23.5{\pm}3.5$) recruited for this study. Each stairs with the same height and length(l8cm and 90cm) under the Korean Constructional Law but three different widths(26cm, 31cm and 36cm) were conducted for this study. One force plate(9286AA, Kistler Co.) was put on third stairs. One-way ANOVA was performed to find the stair width effects during stair walking and the following findings ware obtained. There was significantly decreased in ankle resultant joint moment at Pull-Up phase(p<.05) and, significantly increased in knee extension moment during mid-stance phase as stair width increase(p<.05), but there was no significance in ankle resultant joint moment was found at Forward Continuance Phase in Ascending Stair Walking and There was significantly increased in ankle resultant joint moment as stair width increase during mid-stance phase(p<.05) and no significance in knee and hip resultant moments among the stair width in descending stair walking.

• Journal of the Korean Orthopaedic Association
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• v.54 no.3
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• pp.254-260
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• 2019

Purpose: To evaluate the relationship between the knee function at 1 year postoperation and the gap difference (90° flexion gap-extension gap) in total knee replacement. Materials and Methods: Eighty-two consecutive osteoarthritis knees that underwent primary total knee replacement using navigation from March 2017 June 2017 were evaluated prospectively. The gap was measured using navigation after reducing the patella with towel clips. After checking the average values of the medial and lateral gaps at extension and 90° flexion knee, the gap difference (90° flexion gap-extension gap) was calculated. The knees were divided into three groups according to the gap difference (gap difference<0 mm, 0 mm≤gap difference<2 mm, 2 mm≤gap difference). The Knee Society score (KSS) and maximal knee flexion were compared at 1 year postoperation among three groups. Results: The numbers of knees according to groups were 37, 29, and 16 knees in regular order. The average of the KSS knee, KSS function, and maximal knee flexion at the 1-year follow-up were 81.21±8.31, 71.34±9.84, and 126.48°±7.28°, respectively. No statistically significant difference in KSS was observed among the 3 groups. The third group (2 mm≤gap difference) showed a larger maximal knee flexion than the other groups in the Mann-Whitney test. Conclusion: The group of total knee replacement (2 mm≤90° flexion gap-extension gap) showed larger maximal knee flexion than the other groups at the 1-year follow-up in statistics.

• 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.

• The Journal of the Korea Contents Association
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• v.9 no.1
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• pp.323-330
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• 2009

Objectives: There are many reasons to restrict extension of knee. Unless we can find any structural deformities from patients, we don't have any clue of helping this condition except give them some instruction of exercise of strengthening anterior thigh muscles and releasing extensor muscle group of lower extremities. In this study, the author reports new case, using technique of releasing restriction of knee movement based on Sacro Occipital Technique. Method: From the day of notifying 14yrs. old patient's extension restriction of knee, it had have 7 trials of having S.O.T category Ⅰ. technique procedure. Result: The patient can stand without extension restriction of knee. Conclusion: In many case, muscle soft tissue work helps releasing hamstring tension so that we can make patient stand with straightly extended knee position but if this method is not working then S.O.T category Ⅰ. technique procedure may be considerable to improve this condition.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.3
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• pp.153-160
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• 2017

Gait analysis has been conducted in various environments, but the biomechanics during the transition from uphill walking to downhill walking have not been reported. The purpose of this study is to investigate the knee and ankle joint kinematics and kinetics during walking on a triangle-shaped slope compared with those during level walking. Kinematic and kinetic data of eighteen participants were obtained using a force plate and motion capture system. The greater peak ankle dorsiflexion angle and moment and the peak knee extension moment were observed (p<0.05) during both uphill and downhill walking on the triangle-shaped slope. In summary, uphill walking on a triangle-shaped slope, which showed a peak knee flexion of more than $50^{\circ}$ with greater peak knee extension moment, could increase the risk of patellofemoral pain syndrome. Downhill walking on a triangle-shaped slope, which involved greater ankle dorsiflexion excursion and peak ankle dorsiflexion, could cause gastrocnemius muscle strain and Achilles tendon overuse injury.

• Korean Journal of Applied Biomechanics
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• v.18 no.3
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• pp.33-42
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• 2008

The purpose of this study was to analyze kinematic variables during Side kick motion in Taekwon Aerobics. The subjects of this study were the 7 skilled and 7 unskilled female college students. A QTM and an Auto Track were used to acquire raw data. The sampling rates camera was 100 Hz. The parameters were calculated and analyzed with Visual3D and SPSS 12.0. The results were as following; 1. In the elapsed time, there was no significance difference statically between a skilled and unskilled group. 2. In the cases of knee angle, there was significant difference statically at Maximum Knee Flexion2(p=0.046, F=4.925). 3. In the cases of knee angular velocity, there was significant difference statically at Maximum Knee Flexion1(p=0.031, F=5.940). 4. In the flexion/extension of hip angle, there was significant difference statically at Maximum Knee Flexion2(p=0.012, F=8.668). 5. In the abduction/adduction of hip angular velocity, there was significant difference statically at Minimum Knee Flexion (p=0.019, F=7.324). 6. In the external rotation/internal rotation of hip angular velocity, there was significant difference statically Minimum Knee Flexion(p=0.005, F=11.87).

• Journal of rehabilitation welfare engineering & assistive technology
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• v.10 no.3
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• pp.207-214
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• 2016

The aim of this study was to evaluate Influence on intra-limb coordination in individuals wearing knee brace during walking. Seven healthy male adults ($32.3{\pm}2.7$ years old, $175.2{\pm}3.8cm$, $76.2{\pm}8.7kg$) participated. They wore knee brace or didn't wear any knee brace and were asked to walk along a 10 m long walkway. Spatiotemporal parameters, angles of the lower limbs, and intra-limb continuous relative phase (CRP) were measured and calculated. No differences of spatiotemporal parameters were shown (all p > 0.05). There were no changes in the angle and its range of motion (ROM) in the hip for the subjects as wearing knee brace, while ROM ($65.5{\pm}3.7^{\circ}$ vs. $60.5{\pm}3.5^{\circ}$, p < 0.05) of the angle and maximum flexion angles (stance: $31.9{\pm}4.6$ vs. $25.6{\pm}5.5$, swing: $76.7{\pm}3.1$ vs. $68.9{\pm}3.4$, all p < 0.05) in the knee significantly decreased. No changes in ROM of angle in the ankle were shown, whereas maximum dorsiflexion decreased ($22.4{\pm}2.6$ vs. $19.2{\pm}2.1$, p < 0.05) and maximum plantarflexion increased ($9.5{\pm}3.0$ vs. $15.7{\pm}2.2$, p<0.05). There were no changes in most of CRP between joints. CRP between the hip and knee joints decreased ($93.0{\pm}7.8$ vs, $84.7{\pm}4.9$, p < 0.05). Most of CRP standard deviation increased (between the hip and ankle joint during swing: $25.1{\pm}6.7$ vs. $32.4{\pm}1.9$, between the knee and ankle joint during stance: $46.0{\pm}12.9$ vs. $80.1{\pm}31.1$, between the knee and ankle joint during swing: $34.5{\pm}4.1$ vs. $37.6{\pm}3.1$, all p < 0.05). These results indicated that wearing knee brace affected joint angle and intra-limb coordination, but less affected gait features.