• Journal of the Korean Society of Physical Medicine
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• v.16 no.3
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• pp.21-27
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• 2021

PURPOSE: This study examined the relationship between the severity of a hallux valgus (HV) deformity and the kinetic three-dimensional ground reaction force (GRF) through a motion analysis system with force platforms in individuals with a HV deformity during normal speed walking. METHODS: The participants were 36 adults with a HV deformity. The participants were asked to walk on a 6 m walkway with 40 infrared reflective markers attached to their pelvic and lower extremities. A camera capture system and two force platforms were used to collect kinetic data during gait. A Vicon Nexus and Visual3D motion analysis software were used to calculate the kinetic GRF data. RESULTS: This research showed that the anterior maximal force that occurred in the terminal stance phase during gait had a negative correlation with the HV angle (r = -.762, p < .01). In addition, the HV angle showed a low negative correlation with the second vertical maximal force (r = .346, p < .05) and a moderate positive correlation with the late medial maximal force (r = .641, p < .01). CONCLUSION: A more severe HV deformity results in greater abnormal translation of the plantar pressure and a significantly reduced pressure force under the first metatarsophalangeal joint.

• IEMEK Journal of Embedded Systems and Applications
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• v.3 no.2
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• pp.82-90
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• 2008

In this paper, we introduce a biped walking robot which can do static walking with 22 degree-of-freedoms. The developed biped walking robot is 480mm tall and 2500g, and is constructed by 22 RC servo motors. Before making an active algorithm, we generate the motions of robot with a motion simulator developed using C language. The two dimensional simulator is based on the inverse kinematics and D-H transform. The simulator implements various motions as we input the ankle's trajectory. Also the simulator is developed by applying the principle of inverted pendulum to acquisite the center of gravity. As we use this simulator, we can get the best appropriate angle of ankle or pelvic when the robot lifts up its one side leg during the walking. We implement the walking motions which is based on the data(angle) getting from both of simulators. The robot can be controlled by text shaped command through RF signal of wireless modem which is connected with laptop computer by serial cable.

• Korean Journal of Applied Biomechanics
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• v.27 no.1
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• pp.67-74
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• 2017

Objective: The purpose of this study was to apply a general linear model in statistics to marker position vectors used to study human joint rotational motion in biomechanics. Method: For this purpose, a linear model that represents the effect of the center of hip joint rotation and the rotation of the marker position on the response was formulated. Five male subjects performed hip joint functional motions, and the positions of nine markers attached on the thigh with respect to the pelvic coordinate system were acquired at the same time. With the nine marker positions, the center of hip joint rotation and marker positions on the thigh were estimated as parameters in the general linear model. Results: After examining the fitted model, this model did not fit the data appropriately. Conclusion: A refined model is required to take into account specific characteristics of longitudinal data and other covariates such as soft tissue artefacts.

• Hip & pelvis
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• v.36 no.2
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• pp.77-86
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• 2024

Knowledge of the relationship between the hip and spine is essential in the effort to minimize instability and improve outcomes following total hip arthroplasty (THA). A detailed yet straightforward preoperative imaging workup can provide valuable information on pelvic positioning, which may be helpful for optimum placement of the acetabular cup. For a streamlined preoperative assessment of THA candidates, classification systems with a capacity for providing a more personalized approach to performance of THA have been introduced. Familiarity with these systems and their clinical application is important in the effort to optimize component placement and reduce the risk of instability. Looking ahead, the principles of the hip-spine relationship are being integrated using emerging innovative technologies, promising further streamlining of the evaluation process.

• Physical Therapy Korea
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• v.5 no.4
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• pp.41-51
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• 1998

The right hip abductor musculature has been reported to demonstrate "stretch weakness" attributable to chronic elongation imposed by standing posture common to right-handed healthy persons. Kendall and associates have described the concept of "stretch weakness",. The purpose of this study was to assess isometric hip abduction torque and surface electromyographic activity (using MYOMED 432) in a sample of 40 healthy right-handed persons (20 male, 20 female), all of whom agreed to participate in the study, and compare side difference in the hip abductor musculature. In order to assure the statistical significance of the results, the paired t test was applied at the .05 level of significance. The results were as follows: 1) The difference in apparent leg length of right and left legs was significant at the .05 level. 2) There was a significant difference between right and left pelvic height (standing position) at the 05 level measurements, and scapula height at the .05 level. 3) Power measurements and action potentials of right hip abductor were greater than the left hip abductor regardless of the range of joint motion (inner range, outer range) 4) The difference in muscle power and action potentials according to inner or outer range of both hip abductor were significant at the .05 level. 5) In supine during active left hip abduction, the appearance of action potentials in the right hip abductors is indicative of contra-lateral effect (p<.05) These results suggest: In healthy right-handed persons, the apparent leg length on the right is longer than on the left, and pelvic height is elevated on the right side. Muscle those and muscle action potentials of the right hip abductor are higher than those of the left hip abductor in the lengthened position. Therefore, the results in this study are contrary to Kendall's. This type of study should be carried out in many physical therapy departments.

• Korean Journal of Applied Biomechanics
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• v.26 no.1
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• pp.39-50
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• 2016

Objective: The purposes of this study were to compare the kinematics of a two-arm kettlebell swing between experts and beginners and to identify the correct postures and biomechanical key points in an attempt to prevent sports injuries induced by a kettlebell swing. Methods: Four experts (height, $169.7{\pm}1.5cm$; weight, $70.5{\pm}1.8kg$; age, $32.0{\pm}1.0years$) licensed to teach kettlebell exercises and three beginners (height, $173.7{\pm}4.1cm$; weight, $78.3{\pm}3.8kg$; age, $30.0{\pm}1.4years$) with no kettlebell exercise experience participated in this study. Each participant performed 15 repetitions of a two-arm kettlebell swing using a 16-kg weight. Joint angles, angular velocities, and peak angular velocity sequences were calculated and compared between the two groups. Results: Large ranges of motion (ROM) of the pelvic angle and hip joints were detected in the experts, while beginners showed greater ROM of the shoulder joint. Peak angular velocity magnitudes and sequences were significantly different between the two groups. Experts lifted the kettlebell upward using the hip joints, pelvis, and shoulder joints (proximal to distal order) sequentially and lowered it using the reverse order of peak angular velocities from the shoulder to hip joints. Conclusion: Mobility of the pelvic segment and hip joint are required, while stability of the other joints is needed to produce appropriate two-arm kettlebell swings. The activation and coordination of the gluteal and hamstring muscles are key points in kettlebell exercises.

• Journal of muscle and joint health
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• v.21 no.2
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• pp.97-105
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• 2014

Purpose: The purpose of this study was to identify the effects of an aquatic exercise program on physical fitness, body composition, and gait characteristics using trunk and pelvic angle in women living in urban fringe area. Methods: An aquatic exercise program consists of exercise in a swimming pool and self-help group activity with 16 women living in urban fringe (mean age: 63 years) for 8 weeks (twice a week for 2 hours). Physical fitness, body composition, trunk and pelvic angle using 2D video motion analyzer, and a questionnaire including socio-demographic variables were measured from July to August, 2013. Data were analyzed using a paired t-test with the SPSS/WIN 18.0 program. Results: At the end of 8 weeks intervention, there were significant decreases on body weight (p=.025), body fat (p=.030) and BMI (p=.011). There were significant increases on muscle strength (p=.001) and flexibility (p=.015). Trunk angle was significantly improved, which means participants less moved their body from side to side when they walked (p=.001). Conclusion: From this results, the aquatic exercise program could be an effective nursing intervention to improve physical fitness, body composition, and gait ability for women living in urban fringe area.

• The Journal of Korean Physical Therapy
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• v.2 no.1
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• pp.35-46
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• 1990

The right hip adbuctor musculature has been reported to demonstrate 'stretch weakness' attributable to chronic elongation imposed by standing posture common to right-handed healthy persons. Kendall and associates have described the concept of 'stretch weakness'. The purpose of this study was to assess isometric hip abduction torque and surface electro-myographic activity (using MYOMED 432) in a sample of 40 healthy right-handed persons (20 male, 20 female), all of whom agreed to participate in the study, and compare side difference in the hip abductor musculature. In order to assure the statistical significance of the results, the paired t-test was applied at the .05 level of significance. The results were as follows : 1. The difference in apparent leg length of right and left legs was significant at the .05 leve1. 2. There was a significant difference between right and left pelvic height (standing position) at the .005 level measurements, and scapula height at the .05 level. 3. Power measurements and action potentials of right hip adbuctor were greater than the left hip adbuctor regardless of the range of joint motion (inner range, outer range). 4. The difference in muscle power and action potentials according to inner or outer range of both hip abductor were significant at the .05 level. 5. In supine during active left hip abduction, the appearance of action potentials in the right hip abductors is indicative of contra-lateral effect (p<.005). These results suggest : In healthy right-handed persons. the apparent leg length on the right is longer than on the left, and pelvic height is elevated on the right side. Muscle torque and muscle action potentials of the right hip adbuctor art higher than those of the hip abductor in the lengthened position. Therefore, the results in this study are contrary to Kendall's. This type of study should be carried out in many physical therapy departments.

• Journal of Radiation Industry
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• v.17 no.4
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• pp.385-390
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• 2023

The uterus, one of women's reproductive organs, is also closely related to women's health. Among them, hemorrhagic luteal cysts, one of the causes of pelvic pain that women often experience, were observed through CT and ultrasound, and the quality of images was evaluated through quantitative and qualitative evaluations. This study sought to find out whether the test method is more helpful to patients during CT and ultrasound. This study was conducted on 15 adolescent women and 15 adult women(21.31±3.45 average age). The equipment used for filming used EC3-10X (3~10 MHZ) and Philips Mx8000 iCT 256 among Endocavity Probes among Ecube Platinum. After setting a constant ROI on the cyst and the interface as a quantitative analysis method, SNR and CNR values were measured on a 5-point scale based on image quality, lesion clarity, image distortion, clarity of the interface, and motion artifacts (p<0.05). Independent t-test and Mann Whiteny U were performed, and the statistical program used was noted when SPSS (Version 22.0 for windows software package, Chicago, IL, USA) was statistically less than 0.05. Comparing the SNR and CNR values for this experiment, it can be seen that the SNR value was higher in the case of CT images(p<0.05). As a result of the qualitative evaluation, the quality of the image, the clarity of the lesion, the distortion of the image, the clarity of the interface, and the clarity of the boundary were measured on a 5-point scale based on the movement artifact. Comparing each score, CT images scored higher with a finer difference than ultrasound images(p<0.05). In conclusion, both test methods showed excellent results in finding the patient's lesions. However, in quantitative and qualitative evaluations, CT produced higher results in detecting lesions than ultrasound. However, for cyst tests that require continuous observation, ultrasonography, a non-invasive method that is advantageous for patients, will be clinically useful. Therefore, observing the patient's lesions by appropriately distributing these two test methods will provide optimal diagnostic information. These results will be useful for providing clinical basic data and educational materials to CT and US users in the future.

• Korean Journal of Applied Biomechanics
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• v.21 no.2
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• pp.223-230
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• 2011

The purpose of this study was to analysis the effect of form and hardness of outsoles on the motion of the lower extremity joints and on foot pressure during gait. The subjects were 15 women(mean age, $48.5{\pm}2.4$ years), who had no serious musculoskeletal, coordination, balance or joint/ligament problems within 1 year prior to the study. The pelvic tilt, joint angles at the lower extremities and the vertical ground reaction force(GRF) were compared during gait with 3 types of shoes (A, B, C) by using one-way repeated ANOVA(p<.05). During gait, the peak tilt angle and the range of motion(ROM) of the ankle and knee joints were found to be significantly different among the 3 types of shoes. The type C shoes showed a significantly lower mean second maximum vertical GRF than types A and B. The curved outsoles of type C shoes, which had a form and hardness different from those of A and B, was designed strategically for walking shoes to provide stability to the Additionally, type C induced the dispersion of eccentric pressure and made the center of pressure roll over to the center line of the foot.