• The Journal of Korea Robotics Society
• /
• v.12 no.2
• /
• pp.107-115
• /
• 2017

In this paper, four-bar linkage mechanism for the knee joint is developed which is used in prosthetics. But unlike the prosthetics, the feature of this mechanism is that the instantaneous center of rotation of the four-bar linkages can be moved behind the ground reaction force vector so that it can be passively supported without any external power. In addition, this mechanism is developed similar to the structure of the human knee joint for eliminating the sense of heterogeneity of the wearer. In order to design the mechanism with these two objectives, optimization design process is done using the PIAnO tool and detailed design is carried out through optimized variable values. The developed mechanism is attached to the robot which can assist the hip and ankle joints. In order to verify the operation of the developed knee mechanism, an insole type sensor was attached to the shoes to compare data values before and after wearing the robot. Result data showed that wearer wearing the exoskeleton robot with the knee mechanism was the same value regardless of whether the heavy tool is loaded or not.

• Korean Journal of Applied Biomechanics
• /
• v.27 no.2
• /
• pp.109-116
• /
• 2017

Objective: This study aimed to investigate the relationship between leg stiffness and kinematic variables according to load while running. Method: Participants included eight healthy men (mean age, $22.75{\pm}1.16years$; mean height: $1.73{\pm}0.01m$; mean body weight, $71.37{\pm}5.50kg$) who ran with no load or a backpack loaded with 14.08% or 28.17% of their body weight. The analyzed variables included leg stiffness, ground contact time, center of gravity (COG) displacement and Y-axis velocity, lower-extremity joint angle (hip, knee, ankle), peak vertical force (PVF), and change in stance phase leg length. Results: Dimensionless leg stiffness increased significantly with increasing load during running, which was the result of increased PVF and contact time due to decreased leg lengths and COG displacement and velocity. Leg length and leg stiffness showed a negative correlation (r = -.902, $R^2=0.814$). COG velocity showed a similar correlation with COG displacement (r = .408, $R^2=.166$) and contact time (r = -.455, $R^2=.207$). Conclusion: Dimensionless leg stiffness increased during running with a load. In this investigation, leg stiffness due to load increased was most closely related to the PVF, knee joint angle, and change in stance phase leg length. However, leg stiffness was unaffected by change in contact time, COG velocity, and COG displacement.

• Journal of muscle and joint health
• /
• v.12 no.1
• /
• pp.69-80
• /
• 2005

Purpose: The purpose of this study was to analyse the effects of Tai Chi on the muscle strength and flexibility. Method: 10 articles from Medline search of foreign journals(1981-2003) and 4 from Korean nursing journals (1981-2003) were surveyed. The research are analyzed according to research design, subjects, and dependent variables. Results: Research on Tai Chi Exercise increased rapidly in the 1990's. The experimental research design was more reported than the comparative design. The experimental design included; 21.4% one group pre-posttest design, 35.7% quasi-experimental design and 28.6% randomized design. Out of the subjects; 64.4% of papers were healthy older people, and 35.6% of papers were patients with osteoarthritis or rheumatoid arthritis. Style of Tai Chi was mostly used Yang or Sun form. Muscle strength was usually measured at lower extremity or grip strength. Classical Yang style or Long form was more effective to improve muscle strength. 75% of papers were significantly improvement in grip strength and 71.4% of papers in flexibility. Conclusion: To properly study the positive effects of Tai Chi exercise, it is suggested that meta analysis needs to be done to integrate the various results.

• Journal of Korean Foot and Ankle Society
• /
• v.17 no.4
• /
• pp.243-250
• /
• 2013

Diabetic Charcot arthropathy is a severe joint disease in the foot and ankle that can result in fracture, permanent deformity, limb loss. Although recent research has improved our level of knowledge regarding its etiology and treatment, it still remains a poorly understood disease. It is a serious and potentially limb-threatening lower-extremity late complication of diabetes mellitus and its diagnosis is commonly missed upon initial presentation. Clinicians treating diabetic patients should be vigilant in recognizing early signs of acute Charcot arthropathy, such as pain, warmth, edema, or pathologic fracture in a neuropathic foot. Early detection and prompt treatment can prevent joint and bone destruction. If left untreated, it can reduce overall quality of life and dramatically increase morbidity and mortality of patients. The goal of this manuscript is to evaluate the current concepts of Charcot arthropathy through review of various literature and help clinicians decide the treatment strategy.

• Journal of Society of Preventive Korean Medicine
• /
• v.12 no.2
• /
• pp.185-195
• /
• 2008

The purpose of this investigation is comparing two groups one applied with taping therapy the other with controlled causes variation in pain substances of blood ${\beta}$-endorphin, serotonin with taping therapy. 12 male students of S college divided into two groups each 6 experimental and controlled with no history of flexion and extention of lower extremity focused on knee joint. Experimental group applied with elastic taping before experiment at quadriceps, calf muscles, hamstrings and tibialis anterior, controlled group didn't applied any taping therapy. Bruce protocol of maximal progressive loading exercise implemented 5 minutes after blood samples were extracted. And 5 minutes after the exercise blood samples also were taken and made investigation. Data before and after investigation were operated on SPSS Ver. 12.0 for Window(Kor.). P value 0.05. The affirmative effects of this investigation was proved with increased ${\beta}$-endorphin and decreased serotonin that cause reducing pain.

• Journal of the Korea Society of Computer and Information
• /
• v.26 no.5
• /
• pp.55-60
• /
• 2021

This study aims to investigate the effects of 4 weeks visual biofeedback training on the knee joint angle and muscle activities of lower extremity. The participants in this study were 15 volunteers with hyperextended knee. To improve the hyperextended knee, visual biofeedback training was used during 4 weeks. The training is an exercise to maintain the balance between the anterior weight bearing and posterior weight bearing of the plantar foot. The knee joint angle significantly increased and the muscle activity of tibialis anterior was significantly decreased after visual biofeedback training. It was confirmed that visual biofeedback training of correcting hyperextended knee through the information on the plantar pressure distribution has a therapeutic effect.

• Korean Journal of Applied Biomechanics
• /
• v.22 no.3
• /
• pp.315-324
• /
• 2012

The purpose of current study was to investigate the effects of the heights on the lower extremities, torso and neck segments for energy dissipation during single-leg drop landing from different heights. Twenty eight young healthy male subjects(age: $23.21{\pm}1.66yr$, height: $176.03{\pm}4.22cm$, weight: $68.93{\pm}5.36kg$) were participated in this study. The subjects performed the single-leg drop landing from the various height(30, 45 & 60 cm). Force plates and motion-capture system were used to capture ground reaction force and kinematics data, respectively. The results were as follows. First, the ROM at the ankle, knee, hip and trunk was increased with the increased heights but the ROM at the neck was increased in the 60cm. Second, the angular velocity, moment and eccentric work at the ankle, knee, hip, trunk, and neck was increased with the increased heights. Third, the contribution to total work at the knee joint was not significantly different, while the ankle joint rate was decreased and hip and neck rate was increased in the 60cm, and trunk rate was increased with the increased heights. Lastly, the increase in landing height was able to augment the level of energy dissipation not only at the lower extremities but also at the trunk and neck. The findings showed that drop landing affect trunk and neck with lower extremity joints. Therefore, we need to consider that trunk and neck strengthening including stability should be added to reduce sports injury during prevention training.

• Archives of Reconstructive Microsurgery
• /
• v.8 no.2
• /
• pp.176-183
• /
• 1999

Chronic osteomyelitis have been treated with wound dressing and antibiotics therapy often results in healing but foul odor pus discharges from the fibrotic soft tissues reactivates and requires appropriate control of the infection. Debridement of the wound, curettage and sequestrectomy, bone graft and immediate free flap transplantation is the curative protocol for the chronic osteomyelitis in the lower extremity. Authors have treated 7 cases of chronic osteomyelitis in the lower extremity with microsurgical free tissue transplantation at Department of Orthopedic Surgery, Chonbuk National University Hospital from December 1993 through February 1998. The results are as follows. 1. The chronic osteomyelitis occurred in tibial shaft in 4 cases, in calcaneus 2 cases and in femur 1 case. 2. Duration of the chronic osteomyelitis was at average 31.6 years. 3. Squamous cell carcinoma in the surrounding fibrotic tissue was biopsied in 1 case. 4. 4 cases had no trauma and occurred through hematogenous infection and 3 cases had fracture trauma. 5. Wound debridement and immediate free muscle transplantation had done in 5 cases and wound debridement, sequestrectomy and immediate free muscle transplantation in 2 cases. 6. Rectus abdominis muscle transplantation had peformed in 4 cases(57.1%), latissimus dorsi mucle 1 case(14.3%), latissimus dorsi myocutaneous 1 case(14.3%) and gracilis 1 case (14.3%). 6 cases of 7 were success(85.7%). 7. 1 case of failed latissimus dorsi musculocutaneous flap in thigh had done above knee amputation and 1 case of chronic posttraumatic osteoarthritis of the ankle joint had done below knee amputation at other hospital.

• Journal of the Ergonomics Society of Korea
• /
• v.10 no.2
• /
• pp.15-22
• /
• 1991

Gait analysis techniques are widely used in Europe and the United States to investigate the loosening problems of total joint implantation and to improve the technologies in designing prosthetic devices. In Korea, however, the gait data are rarely found. Recently, as the standards of living become improved, the number of lower extremity operation patients increase rapidly. Therefore, a study on the gait characteristic parameters for Koreans is of great importance. In this study, time-distance gait parameters and ground reaction fore are analyzed using a FOANAS system developed by Pohang Institute of Science and technology (POSTECH). Gait parameters of Korean normal adults were preceded and comparisons were made for the distinction of sex and age.

• The Journal of the Korean bone and joint tumor society
• /
• v.19 no.1
• /
• pp.33-36
• /
• 2013

Leiomyoma is a benign solitary tumor which is originated from a smooth muscle cell and grows slowly. It is most commonly found in the uterus and can develop anywhere that smooth muscle is present, including esophagus, lower extremity, stroma of GI tract, and pleura. However, the occurrence of leiomyoma in the hand is so uncommon. We present one case of solid type leiomyoma found in the right $4^{th}$ finger of a young woman.