• Korean Journal of Applied Biomechanics
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• v.13 no.3
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• pp.163-180
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• 2003

This paper aims at collecting the guantitative data of kenematic variables by analysing the gait patterns of the normal adult men and the handicapped. The gait motions were taped with 4 video cameras, the cinematographic analyses were performed by the DLT technique of three dimensional image treatment. The following results were obtained in the analysis of the variables: 1. The ratio of stance time and swing time did not show any significant difference in the groups of the normal men and the handicapped when both foot of the former and the right feet of the latter were compared. The stride peeriod time of these two groups were 1.12 and 1.11 second, respectively. 2. In the handicapped group, the step width was wider, the step length and stride length were shorter, and especially, the step length of the right foot was shorter, 3. The small vertical displacement of left toes of the handicapped group showed that the heal contact and the left midstance are almost simultaneous. 4. The two groups have almost the same horizontal displacement of the center of gravity and the same vertical rate of extension. In view of the velocity of the center of gravity the normal adults showed the constant speed of movement. However, the handicapped adults were reduced from the right midstance to the right toe-off. 5. The handicapped showed prominently low angle on the left toe-off in the ankle joint angle, they also had the tendency to walk in the patterns of extended knee in the knee joint angle. Both the handicapped and the normal had the hyperextension on the toe-off in the hip joint angle. In the back and front angle of body, both showed the slightly back-sided walking positions. 6. Both groups had the abduction of both feet in foot placement angle, but the handicapped did not show serious abduction of left midstance.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.6 no.2
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• pp.31-38
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• 2000

The influence of the genu varum and the genu valgum in two groups of twenty adult man with deformation on hip joint, knee joint, ankle joint is as follows. 1. Each and all, the statistics that measure tibiofemorial angle indicated the group of the genu varum 168 1.42 and the group of the genu valgum 193 2.21, that was more larger or smaller than normal angle 183 of tibiofemorial. The measure Q-Angle(patellofemorial) indicates the group of the genu varum 9 1.5, the genu valgum 19 2.3, that was larger or smaller than normal angle 13. 2. It showed that range of motion hip joint adduction in the group of the genu varum was more larger than normal range of motion hip joint abduction in the group of the genu valgum was more larger than normal range of motion, hip joint internal rotation in the group of the genu valgum was more larger than normal range of motion, hip joint external rotation in the group of the genu varum was more larger than normal range of motion. 3. range of motion knee joint flexion was simillar to two groups of the genu varum and the genu valgum. On tibial tortion of the leg, the group of the genu varum indicated medial tibial tortion, and the genu valgum indicated lateral tibial tortion. 4. Each groups of the genu varum and the genu valgum in plantarflexion and dorsiflexion of ankle joint. With peak angle, the group of the genu varum showed toe-in that was more smaller than normal angle, and the group of the genu valgum showed toe-out that was more larger than normal angle.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.4
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• pp.817-819
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• 2007

The purpose of this work is to develop a measurement system of the pendulum test with minimal restriction of experimental environment and little influence of noise. In this work, we developed a vision system without any line between markers and a camera. The system performance is little influenced by the experimental environment, if light are sufficient to recognize markers. For the validation of the system, we compared knee joint angle trajectories measured by the developed system and by the magnetic sensor system during the nominal pendulum test and the maximum speed voluntary knee joint rotation. The joint angle trajectories of the developed system during both tests matched well with those of the magnetic system. Therefore, we suggest the vision system as an alternative to the previous systems with limited practicality for the pendulum test.

• Journal of the Korean Arthroscopy Society
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• v.6 no.2
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• pp.101-108
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• 2002

Purpose: To evaluate the clinical results of anterior cruciate ligament (ACL) reconstruction and to know the results of physeal injury by transphyseal tunnel in adolescents who had remaining growth potential. Materials and Methods : This study involved 12 patients under 19 years old out of 445 patients, who underwent ACL reconstruction between 1993 and 2001. The mean age at the time of operation was 15.9 $(13.1\~16.9)$ years and fellow-up period was 45.1 $(24\~120.6)$ months in avrarge. Autologous quadrupled hamstring tendon was used as graft in 11 cases and bone-patellar tendon-bone in 1 case. Clinical results were evaluated by Lysholm Knee Scoring Scale, range of motion and return to preinjury sports activities. Radiologic results were evaluated by $Telos^{\circledR}$ device. Bone maturity were analyzed by chronological age, standing height and the width of growth plate in AP and lateral view of knee joint at preoperatively. The growth disturbances were evaluated by measuring femorotibial angle, anatomical and mechanical lateral distal femoral angle, mechanical medial proximal tibial angle and leg length and by comparing those of uninjured site in last follow-up teleoroentgenogram. Results : The mean Lysholm Knee score was 51 $(25\~63)$points preoperatively and 98 $(94\~100)$ points at last follow up. The mean anterior displacement of the tibia by using $Telos^{\circledR}$ device was improved from 13.5 $(6\~27)$ mm to 2.9 $(1\~4)$ mm and there were no significant instabilities of the knee in all cases. There were no leg length discrepancies over 1 cm and no statistically significant abnormal alignment of the knee joint in all cases. Conclusion: ACL reconstruction using transphyseal tunnel for restoring stability and knee function is assumed as a good mettled of treatment without significant leg length discrepancy and abnormal alignment of the knee joint.

• Physical Therapy Korea
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• v.11 no.3
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• pp.85-90
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• 2004

The purpose of this study was to find the difference in muscle firing rate between each muscle according to the knee angle with the quadriceps femoris which is a representative action muscle of the lower extremity. Seven normal healthy subjects were recruited. The median frequency (MDF) of muscle contraction was recorded from vastus lateralis, vastus medialis, and rectus femoris muscles using the surface EMG, in 5 seconds, during maximal isometric knee extension. The data were analyzed by the two-way repeated ANOVA. The results of the study were as follows: 1) median frequency of muscle contraction was significantly higher at the vastus lateralis, vastus medialis, and rectus femoris in descending order. 2) median frequency of muscle contraction was significantly higher at the $30^{\circ}$, $60^{\circ}$, and $90^{\circ}$ in descending order. Consequently, muscle recruitment at the knee decreases the EMG activity of the lengthened muscle. This study suggests that the change in EMG activity at different muscle lengths resulted in affecting the muscle firing rate during the knee extension.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.51-53
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• 2005

Considerable noise is sometimes associated with degeneration of the hee joint surface. Such noise may indicate roughness or softening of the cartilage surfaces, and may be a useful index for early disease. In this study, we have evaluated arthritic pathology using the acoustical analysis of knee joint sounds. During sitting and standing periods, subjects' active knee flexion and extension were monitored. Fundamental frequency, mean amplitude of pitch, jitter and shimmer were analyzed according to the position and the joint angle. The result showed that the fundamental frequency of the 2nd patient group and standing position was higher than the others, and that the pitch of sounds changed unstably. These results suggest that an analysis of knee joint sound might assist non-invasive diagnosis of an articular pathology.

• Biomedical Engineering Letters
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• v.8 no.4
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• pp.345-353
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• 2018

This study suggested a new EMG-signal-based evaluation method for knee rehabilitation that provides not only fragmentary information like muscle power but also in-depth information like muscle fatigue in the field of rehabilitation which it has not been applied to. In our experiment, nine healthy subjects performed straight leg raise exercises which are widely performed for knee rehabilitation. During the exercises, we recorded the joint angle of the leg and EMG signals from four prime movers of the leg: rectus femoris (RFM), vastus lateralis, vastus medialis, and biceps femoris (BFLH). We extracted two parameters to estimate muscle fatigue from the EMG signals, the zero-crossing rate (ZCR) and amplitude of muscle tension (AMT) that can quantitatively assess muscle fatigue from EMG signals. We found a decrease in the ZCR for the RFM and the BFLH in the muscle fatigue condition for most of the subjects. Also, we found increases in the AMT for the RFM and the BFLH. Based on the results, we quantitatively confirmed that in the state of muscle fatigue, the ZCR shows a decreasing trend whereas the AMT shows an increasing trend. Our results show that both the ZCR and AMT are useful parameters for characterizing the EMG signals in the muscle fatigue condition. In addition, our proposed methods are expected to be useful for developing a navigation system for knee rehabilitation exercises by evaluating the two parameters in two-dimensional parameter space.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.363-364
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• 2013

• Journal of the Korea Safety Management & Science
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• v.12 no.4
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• pp.81-86
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• 2010

Despite the importance of cycling postures during cycling performances, there has been a very little research investigating cycling postures and pedaling rate for particularly concerning domestic cyclists. The aim of this study was to analyze correlations and effects between cycling postures and pedaling rate in track cycling. Twelve male racing cyclists (six racing and university cyclists) participated in this research. For this study, seven infrared cameras (Qualisys ProReflex MCU-240s) were used for collecting data and these were processed via QTM (Qualisys Tracker Manager) software. It appeared that pedaling rate had correlations with regard to a shoulder angle (R=-.601) and displacement between shoulder joints(R= -.637), but a knee (R=-.601) and ankle angle (R=.667). Moreover, two multiple regression equations of pedaling rate for cycling postures were significant and R2 of the first order equation y (pedaling rate) = 0.039x (knee angle) - 1.068 was less than the second order equation y = 0.006x2 - 1.287x + 69.674. In conclusion, cycling postures affected the pedaling rate. Further study should be researched on postures in relation to air resistance in a wind tunnel.

• Physical Therapy Korea
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• v.13 no.4
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• pp.1-9
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• 2006

The purpose of this research was to analyze the effects of the increase of the femoral anteversion angle on the unbalanced quadriceps femoris muscle causing the increase of the valgus force on the knee joints and patellofemoral pain syndrome by comparing with the group that shows the smaller femoral anteversion angle. The method for the research was to compare the femoral muscle's activity while the subjects were maintaining the knee joint flexed isometrically for 10 seconds. The evaluation tool for femoral muscle's activity was QEMG-4 (model LXM 3204). The results were as followings. Firstly, in case of the experimental group, the muscle strength of the vastus lateralis muscle was strong while the rectus femoris and vastus medialis were weak. In these facts, we can see the statistically meaningful difference in vastus medialis muscle activity. Secondly, in the muscle activity analysis for vastus lateralis and medialis of the two groups, we could see the vastus lateralis muscle was strong in anteversion wider for experimental group while the vastus medialis muscle contracted far more stronger in anteversion smaller for control group. From these results, we can see the significant differences in muscle recruitment between the two groups. Above results show that if the anteversion becomes wider, vastus medialis muscle will become seriously weaker, on the other hand, vastus lateralis act stronger.