• Journal of radiological science and technology
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• v.42 no.6
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• pp.423-428
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• 2019

The Precise measurement of the knee's Congruence angle is required for diagnosis of patella dislocation. The purpose of this study is to consider the distortion diagram and usefulness about the test of the bilateral side and one side through the evaluating congruence angle from Merchant view of patellofemoral joint to central X-ray. We've evaluated the sulcus angle and Congruence angle following central X-ray's changes when we took Merchant view of patellofemoral joint aimed to right lower limb from human whole body phantom. The subject of the evaluation was classified as normal group and varus group, and the varus group has experimented with External rotation of legs as 15° and 30°. When normal groups result as 0, 7.5, 15 cm, it was measured as 17.25 ± 1.34°, 19.60 ± 1.41°, 20.55 ± 1.77° each. The gap between minimal and maximum angle was 3.3°, and the value was shown as getting bigger when it further away from the centeral X-ray. When Congruence angle in 15° varus group was 0, 7.5, 15 cm, it was each 16.45 ± 1.34°, 17.10 ± 0.99°, 17.80 ± 1.13°. And when Congruence angle in 30° varus group was 0, 7.5, 15 cm, it was measured each 18.35 ± 1.63°, 18.95 ± 1.06°, 19.60 ± 1.41°. The difference between minimum and maximum of angle in 15° varus group and 30° varus group was each 1.35° and 1.25°, the angles have shown as increasing the further away from the center. The patellofemoral joint showed that the congruence angle increases as the further away from Central X-ray, and also it is judged that is possible to change the congruence angle by a degree of varus knee. Thus, accurate measurement of the congruence angle is shown to advantage that methods for examining by split each side at two times than methods for examining both sides at a time. Therefore, it is expected to helpful on the diagnostic side of patella dislocation and subluxation.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.8 no.2
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• pp.31-43
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• 2002

The subjects of this study were 15 woman soccer players and 15 untrained woman students at H-Cheju University. Each subject was measured on the muscle strength and peak torque of knee extensors and knee flexors with isokinetic load ($60^{\circ}$/sec, $180^{\circ}$/sec). The results were as follows: 1. There was no significant difference between right and left leg strength measured isokinetically in each group. 2. The peak torque of knee extensors and flexors was significantly higher in scoccer players than untrainded students (p<0.001). 3. For the angle of knee joint showing the highest peak torque, there was significant difference between soccer players and untrained students in knee extensors(p<0.05) and right flexors (p<0.01). 4. For knee H/Q ratio, there was significant difference between two groups(p<0.05). 5. For the total work and average power at $180^{\circ}$/sec, there was significant difference between two groups in knee extensors(p<0.001) and flexors(p<0.01). 6. In soccer players at $60^{\circ}$/sec, there were significant correlations between peak torque and height and between peak torque and weight.(p<0.001). 7. For the muscular contraction velocity at $60^{\circ}$/sec, there was significant difference between two groups in flexors (p<0.01). 8. For the muscular indurance at $180^{\circ}$/sec in extensors and flexors, there was no significant difference between two groups(p<0.05). In conclusion, there were significantly higher in peak torque, contraction velocity, knee joint's angle with the highest peak torque, H/Q ratio, total work and average power in woman scoccer player than general students. But there was no significant difference in muscular endurance. Soccer performance is based on the various components including muscular endurance that is one of the most important components. So it is necessary that the training method to improve the various components (especially including muscular endurance) should be done.

• Korean Journal of Applied Biomechanics
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• v.22 no.1
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• pp.95-104
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• 2012

The purpose of this study targeted to national cross-country skiers representatives was to implement hypothetical experiment on their patterns of the movements and analysis on kinematic variables occurred while double polling was conducted between starting and finishing phase of 56 meters. Furthermore, it aimed to provide a set of quantitative data to illustrate how to improve one's skill and performance of sprint. In our experiments, we conducted 3-dimension analysis of cycle characteristics, joint angle(hip, knee and elbow), and pole angle. The results showed that at the starting phase, the players did not show a significant difference in attributes of time and distance. In heat 1 where elbow angle and polling starts, the pole angle was noticeably high in heat 1. At the finishing phase, there was a considerable distinction with a high frequency in performing a short polling time and high speed in heat 3. The players showed large extension between the flexion and of the hip angle which indicates high contribution given from the movement of lower body(hip, knee).

• Korean Journal of Applied Biomechanics
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• v.17 no.1
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• pp.191-199
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• 2007

This study was conducted to examine the biomechanical characteristics of open spike in the volleyball to improve the technique of the volleyball spike. The subjects were six male college and high school athletes. The motions of volleyball spike were filmed by using two Sony VX 2000 Video Cameras. The mechanical factors were angle and angular velocity of body segments in the upper and the lower limbs. The conclusions were as follows; 1. The angle of the shoulder joint of the skilled showed larger than that of the unskilled in impacting of the volley ball spike. 2. The angle of the elbow joint of the skilled showed larger than that of the unskilled in impacting of the volley ball spike. 3. The angle of the wrist joint of the skilled showed smaller than that of the unskilled in impacting of the volley ball spike. 4. The angle of the hip joint of skilled showed larger than that of unskilled in impacting of the volley ball spike. 5. The angle of the knee joint of the skilled and the unskilled showed same in take off and impacting of the volley ball spike, and that of the skilled showed smaller than that of the unskilled in take-off touchdown and touchdown after impact of the volley ball spike. 6. The angle of the ankle joint of skilled showed larger than unskilled in take-off of the volley ball spike. 7. The angular velocity of the shoulder joint, elbow joint, wrist joint of the skilled showed faster than that of the unskilled in impacting of the volley ball spike. Taken together the result of them, I have come to conclusion that knee joint angle in touchdown of the take off should be decreased and knee joint angle in take off should be increased, and then stability of the take off should be made and, and that extension of the elbow joint should be made and wrist joint angle decreased and shoulder and hip joint angle increased, and then C.O.G of the arm and hand should be positioned ahead C.O.G of the body in impacting for effective impact of the spike, and that the transfer of the angular velocity of body segments for effective impact of the spike make from the proximal segment to the distal segment at spike in volleyball.

• Journal of Mechanical Science and Technology
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• v.17 no.6
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• pp.825-835
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• 2003

Previous studies have demonstrated the importance of joint angle errors mainly due to skin artifact and measurement errors during gait analysis. Joint angle errors lead to unreliable kinematics and kinetic analyses in the investigation of human motion. The purpose of this paper is to present the Joint Averaging Coordinate System (JACS) method for human gait analysis. The JACS method is based on the concept of statistical data reduction of anatomically referenced marker data. Since markers are not attached to rigid bodies, different marker combinations lead to slightly different predictions of joint angles. These different combinations can be averaged in order to provide a "best" estimate of joint angle. Results of a gait analysis are presented using clinically meaningful terminology to provide better communication with clinical personal. In order to verify the developed JACS method, a simple three-dimensional knee joint contact model was developed, employing an absolute coordinate system without using any kinematics constraint in which thigh and shank segments can be derived independently. In the experimental data recovery, the separation and penetration distance of the knee joint is supposed to be zero during one gait cycle if there are no errors in the experimental data. Using the JACS method, the separation and penetration error was reduced compared to well-developed existing methods such as ACRS and Spoor & Veldpaus method. The separation and penetration distance ranged up to 15 mm and 12 mm using the Spoor & Veldpaus and ACRS method, respectively, compared to 9 mm using JACS method. Statistical methods like the JACS can be applied in conjunction with existing techniques that reduce systematic errors in marker location, leading to an improved assessment of human gait.

• Korean Journal of Applied Biomechanics
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• v.26 no.2
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• pp.161-166
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• 2016

Objective: The purpose of this study was to determine the knee and ankle joint kinematics and kinetics by comparing downhill walking with valley-shape combined slope walking. Method: Eighteen healthy men participated in this study. A three-dimensional motion capture system equipped with eight infrared cameras and a synchronized force plate, which was embedded in the sloped walkway, was used. Obtained kinematic and kinetic parameters were compared using paired two-tailed Student's t-tests at a significance level of 0.05. Results: The knee flexion angle after the mid-stance phase, the mean peak knee flexion angle in the early swing phase, and the ankle mean peak dorsiflexion angle were greater during downhill walking compared with valley-shape combined slope walking (p < 0.001). Both the mean peak vertical ground reaction force (GRF) in the early stance phase and late stance phase during downhill walking were smaller than those values during valley-shape combined slope walking. (p = 0.007 and p < 0.001, respectively). The mean peak anterior GRF, appearing right after toe-off during downhill walking, was also smaller than that of valley-shape combined slope walking (p = 0.002). The mean peak knee extension moment and ankle plantar flexion moment in late stance phase during downhill walking were significantly smaller than those of valley-shape combined slope walking (p = 0.002 and p = 0.015, respectively). Conclusion: These results suggest that gait strategy was modified during valley-shape combined slope walking when compared with continuous downhill walking in order to gain the propulsion for lifting the body up the incline for foot clearance.

• Korean Journal of Applied Biomechanics
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• v.14 no.1
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• pp.83-98
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• 2004

The purpose of this study was to determine the kinematic variables of the hurdling for a korea record holder (A) and a national hurdle representative (B). after the kinematic variables such the distance and the distance and height of C.G, the velocity and the angle were analyzed about the hurdling. The results were summarized as follows; 1. In terms of the distance and the height of C.G, subject A showed long in horizontal distance from C.G to the take-off phase, but showed short in the landing phase. Subject B showed short in horizontal distance from C.G to the take-off phase, and showed long in the landing phase. 2. In terms of the velocity of C.G, Subject A showed fast C.G velocity in horizontal direction to the braking phase, Subject A and B showed slower C.G velority in the landing phase, but Subject A showed height C.G velocity in vertical direction to the to the take-off, the landing, and propulsion phase 3. In terms of the angle of C.G and lean of C.G to front at the braking and the take-off phase. Subject A kept the less angle in the maximum trunk lean to front at the flight phase as comparison with Subject B. 4. In terms of the velocity of the knee and the ankle joint. Subject A showed fast in the resultant velocity of the left ankle joint the take-off phase, but showed slow in the left knee joint. Subject B showed fast in the resultant velocity of the left knee joint the take-off phase, but showed slow in the right knee and the right ankle joint.

• Journal of the Korean Society of Radiology
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• v.15 no.6
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• pp.919-926
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• 2021

In this study, we wanted to find out the optimal angle as a modified tangential projection of the patella. In the experiment, we used Kyoto Kagaku's PBU-50 phantom. In the supine position, the F-T angle was set to 95°, 105°, 115°, 125°, 135°, 145°, and Patella tangential projection images were obtained by varying the X-ray tube angle by 5° so that the angle between the X-ray centerline and tibia at each angle was 5~20°. Image J was used for image analysis and the congruence angle, lateral patellofemoral angle, patellofemoral index and contrast to noise ratio(CNR) were also measured. SPSS 22 was used for statistical analysis, and the mean values of congruence angle, patellofemoral angle, patellofemoral index, and CNR were compared with Merchant method through one-way batch analysis and corresponding sample t-test. As a result of the study, in the case of congruence angle, the angle of incidence of the knee-angle X-ray centerline was 105°-72.5° (20° tangential irradiation), 115°-72.5°, 77.5° (15, 20° tangential irradiation), 125°-82.5° (20° tangential irradiation), lateral patellofemoral angle is 115°-72.5°, 77.5° (15, 20° tangential irradiation), 125°-72.5° (10° tangential irradiation), patellofemoral index is 115°-72.5° (15° tangential irradiation) and 125°-72.5° (10° tangential irradiation) were not significantly different from Merchant method (p> .05). In case of CNR, it is not different from Merchant method at 105°-67.5°, 72.5° (15, 20° tangential irradiation), 115°-67.5°, 72.5°, 77.5° (10, 15, 20° tangential irradiation). (P> .05). Based on the results of this study, high diagnostic value images can be obtained by setting the knee angle and the angle of incidence of the X-ray tube to 115°-72.5° (15° tangential irradiation) during the modified tangential examination of the knee bone. It was confirmed.

• Physical Therapy Korea
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• v.22 no.3
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• pp.12-22
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• 2015

The purpose of this study was to investigate the effect of taping on knee joint for patellofemoral compressive force (PCF) during stair descent for elderly women. Ten healthy elderly women voluntarily participated in this study. A three-dimensional motion analysis system and force plates were used to analyze the movements of the joints for the lower extremities. The results were as follows: There were no significant differences for the maximum PCF, maximum quadriceps contraction force and maximum knee extension moment (p>.05) but, there was a pattern decreasing all values with the taping during stair descent. There were significant differences for the knee and ankle angle on the event of maximum PCF (p<.05) and there was a pattern decreasing all values with the taping during stair descent. Therefore, taping on the knee would be effective to relieve the pain like patellofemoral pain syndrome in the knee joint.

• Korean Journal of Applied Biomechanics
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• v.31 no.1
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• pp.64-71
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• 2021

Objective: This study investigated the different in isokinetic peak strength of the knee joint, and kinetics and kinematics in drop landing pattern of lower limb between the patellofemoral pain syndrome (PFPS) patients and normal. Method: 30 adult females were divided into the PFPS (age: 23.13±2.77 yrs; height: 160.97±3.79 cm, weight: 51.19±4.86 kg) and normal group (age: 22.80±2.54 yrs, height: 164.40±5.77 cm, weight: 56.14±8.16 kg), with 15 subjects in each group. To examine the knee isokinetic peak strength, kinematics and kinetics in peak vertical ground reaction force during drop landing. Results: The knee peak torque (Nm) and relative strength (%) were significantly weaker PFPS group than normal group. In addition, PFPS group had significantly greater hip flexion angle (°) than normal group. Moreover, normal group had significantly greater moment of hip abduction, hip internal rotation, and left ankle eversion than PFPS group, and PFPS group had significantly greater moment of knee internal rotation. Finally, there was significant differences between the groups at anteroposterior center of pressure. Conclusion: The PFPS patients had weakened knee strength, and which can result in an unstable landing pattern and cause of more stress in the knee joints despite to effort of reduce vertical ground reaction force.