• Physical Therapy Korea
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• v.28 no.1
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• pp.27-35
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• 2021

A weak or dysfunctional gluteus medius (Gmed) is related to several pathologies, and individuals with hip abductor weakness have Gmed weakness. This study aimed to systematically review the literature associated with the anatomy and function of the Gmed, and the prevalence, pathology, and exercise of Gmed weakness. Papers published between 2010 and 2020 were retrieved from MEDLINE, Google Academic Search, and Research Information Sharing Service. The database search used the following terms: (glut* OR medius OR hip abduct*) AND weak*. The Gmed plays an important role in several functional activities as a primary hip abductor by providing pelvic stabilization and controlling hip adduction and internal rotation. Weakness of the Gmed is associated with many disorders including balance deficit, gait and running disorders, femoroacetabular impingement, snapping hip, gluteal tendinopathy, patellofemoral pain syndrome, osteoarthritis, iliotibial band syndrome, anterior cruciate ligament injury, ankle joint injuries, low back pain, stroke, and nocturia. Overuse of the tensor fasciae latae (TFL) as a hip abductor due to Gmed weakness can also cause several pathologies such as pain in the lower back and hip and degenerative hip joint pathology, which are associated with dominant TFL. Similarly, lateral instability and impaired movements such as lumbar spine lateral flexion or lateral tilt of the pelvis can occur due to compensatory activation of the quadratus lumborum for a weakened Gmed while exercising. Therefore, the related activation of synergistic muscles or compensatory movement should be considered when prescribing Gmed strengthening exercises.

• Korean Journal of Applied Biomechanics
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• v.24 no.3
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• pp.239-248
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• 2014

The purpose of this study was to quantify kinematic and kinetic characteristics of Yin-yang Bo gait according to their motor expertise, one of the Seokmun Ilwol martial art gait patterns. Yin-yang Bo gait pattern shows initial forefoot contact instead of heel contact, and increased time of stance phase time, internal-external rotation of ankle-knee-hip joints and pelvic. It aims to produce and store the more energy through continuous homeostasis of center of gravity (COG) and performance of stretch-shortening cycle. Some of these characteristics also were similar to the gait modification strategies for reducing knee adduction moment such as toe-out progression, medial thrust, internal rotation of hip joint. To identify the characteristics, four factors of expert Yin-yang Bo gait performance group were compared to that of none expert group; 1) angles of COG displacement and rotation 2) distal joint pre-rotation in internal-external rotation of ankle-knee-hip joints and pelvic, 3) invariability pelvic potential and pelvic segment total energy 4) knee abduction moment. Six healthy(three male) subjects participated in the experiment to perform Yin-yang gait pattern. Three-dimensional and force plate data were collected. Kinematic and kinetic data were compared between two groups using t-tests. Results showed that 1) the peak point of COG internal rotation angle was reduced in expert group, 2) kneeexternal and hip joint -internal and pelvic rotation angle peak frames were more near points in expert group.

• Korean Journal of Applied Biomechanics
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• v.22 no.3
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• pp.325-332
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• 2012

This study aimed to analyze the effects of external load between male and female on angular velocity, moment, and absorbed energy of the lower-extremity joints during drop landing. The study subjects were 9 male($mass=70.82{\pm}4.64kg$, $height=1.71{\pm}0.04m$, $age=24.5{\pm}1.84years$), 9 female($mass=50.14{\pm}4.09kg$, $height=1.61{\pm}0.03m$, $age=23.6{\pm}2.62years$), without any serious musculoskeletal, coordination, balance, or joint/ligament problems for 1 year before the study. The angular velocity, flexion/extension and abduction/adduction moments, and absorbed energy of the lower-extremity joints were compared between the men and women during drop landing under 4 different conditions of external load(0%, 8%, 16%, and 24%) by using two-way repeated ANOVA(p < .05). The women landed with a greater peak angular velocity of the ankle joint, greater peak inversion moment, and lower peak hip-extension moment than the men did, under all 4 conditions. Additionally, the landing characteristics of the women were distinct from those of the men; the women showed a greater peak knee-adduction moment and greater absorbed energy of the knee joint. These differences indicate that anterior cruciate ligament(ACL) strain was greater in the women than in the men and therefore, women may be at a higher potential risk for noncontact injuries of the ACL with an increase in external load.

• Physical Therapy Korea
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• v.18 no.2
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• pp.1-8
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• 2011

The purpose of this study was to investigate the effect of high heeled shoes with the total contact insert (TCI) on the frontal plane of the joints for the lower extremity during the gait. Ten healthy females voluntarily participated in this study and the height of the high heeled shoes was 7 cm. A three-dimensional motion analysis system (VICON) 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 angle value on the event of the gait cycle in the maximum eversion and inversion of the ankle joint, the varus and valgus of the knee joint, and the adduction and abduction of the hip joint (p>.05). But, there was a significant difference or the range of motion in the ankle joint (p<.05). The value of ankle and knee moment with a TCI was less than the value for no TCI. And there were significant differences for the moment value of the maximum inversion and eversion on the ankle joint and for the maximum varus and valgus on the knee joint (p<.05). Therefore, a TCI would be effective in stabilizing the joints of the lower extremities and increasing the balance of a body to reduce the injure from a fall during the gait.

• Journal of the Korean Applied Science and Technology
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• v.35 no.1
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• pp.55-61
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• 2018

The purpose of this study was to analyze the biomechanical differences of lower extremity joints of the frontal plane during sidestep cutting in male and female Judo athletes. In the knee and hip joint, the female group showed a smaller angle than the male group at the time of IC(initial contact). But peak knee joint adduction moment of female group was greater than male group(p<.05). Therefore, female Judo athletes were more likely to injure their knees at the point where their initial foot contacted the ground than male athletes during sidestep cutting.

• PNF and Movement
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• v.20 no.2
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• pp.295-306
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• 2022

Purpose: This study aimed to investigate the effect of robot-assisted gait training on the active ranges of motion, gait abilities, and biomechanical characteristics of gait in patients who underwent lower extremity surgery, and to verify the effectiveness and clinical usefulness of robot-assisted gait training. Methods: This study was conducted on 14 subjects who underwent lower extremity surgery. The subjects participated in robot-assisted gait training for 2 weeks. The active ranges of motion of the lower extremities were evaluated, and gait abilities were assessed using 10-m and 2-min walk tests. An STT Systems Inertial Measurement Unit was used to collect data on biomechanical characteristics during gait. Spatiotemporal parameters were used to measure cadence, step length, and velocity, and kinematic parameters were used to measure hip and knee joint movement during gait. Results: Significant improvements in the active ranges of motion of the hip and knee joints (flexion, extension, abduction, and adduction) and in the 10-m and 2-min walk test results were observed after robot-assisted gait training (p < 0.05). In addition, biomechanical characteristics of gait, spatiotemporal factors (cadence, step length, and velocity), and kinematic factors (gait hip flexion-extension, internal rotation-external rotation angle, and knee joint flexion-extension) were also significantly improved (p < 0.05). Conclusion: The results of this study are of clinical importance as they demonstrate that robot-assisted gait training can be used as an effective intervention method for patients who have undergone lower extremity surgery. Furthermore, the findings of this study are clinically meaningful as they expand the scope of robot-assisted gait training, which is currently mainly applied to patients with central nervous system conditions.

• Korean Journal of Applied Biomechanics
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• v.15 no.3
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• pp.161-173
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• 2005

Recently among several tennis techniques forehand stroke has been greatly changed in the aspect of spin, grip and stance. The most fundamental factor among the three factors is the stance which consists of open, square and closed stance. The purpose of this study was to investigate the relations between the segments of the body, the three dimensional anatomical angle according to open stance patterns during forehand stroke in tennis. For the movement analysis three dimensional cinematographical method(APAS) was used and for the calculation of the kinematic variables a self developed program was used with the LabVlEW 6.1 graphical programming(Johnson, 1999) program. By using Eular's equations the three dimensional anatomical Cardan angles of the joint and racket head angle were defined 1. In three dimensional maximum linear velocity of racket head the X axis showed $11.41{\pm}5.27m/s$ at impact, not the Y axis(horizontal direction) and the z axis(vertical direction) maximum linear velocity of racket head did not show at impact but after impact this will resulted influence upon hitting ball It could be suggest that Y axis velocity of racket head influence on ball direction and z axis velocity influence on ball spin after impact. the stance distance between right foot and left foot was mean $74.2{\pm}11.2m$. 2. The three dimensional anatomical angular displacement of shoulder joint showed most important role in forehand stroke. and is followed by wrist joints, in addition the movement of elbow joints showed least to the stroke. The three dimensional anatomical angular displacement of racket increased flexion/abduction angle until the impact. after impact, The angular displacement of racket changed motion direction as extension/adduction. 3. The three dimensional anatomical angular displacement of trunk in flexion-extension showed extension all around the forehand stroke. The angular displacement of trunk in adduction-abduction showed abduction at the backswing top and adduction around impact. while there is no significant internal-external rotation 4. The three dimensional anatomical angular displacement of hip joint and knee joint increased extension angle after minimum of knee joint angle in the forehand stroke, The three dimensional anatomical angular displacement of ankle joint showed plantar flexion, internal rotation and eversion in forehand stroke. it could be suggest that the plantar pressure of open stance during forehand stroke would be distributed more largely to the fore foot. and lateral side.

• Korean Journal of Applied Biomechanics
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• v.25 no.3
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• pp.363-370
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• 2015

Objective : The purpose of this study was to give the basic data for the cutting movement with the various angels on the poly urethane. Method : Ten healthy men voluntarily participated in this study. A three-dimensional motion analysis system (VICON) and force plates were used to analyze the movements of the joints for the lower extremities. For the statistical analysis the IBM SPSS 21.0 was used to perform repeated measured ANOVA and post-hoc comparison result was used to perform the Scheffe and the level of significance was set up at ${\alpha}=.05$. Results : There were significant differences for the time required for the increasing angles of the cutting movement(p<.05). In addition, there were significant differences for the maximum dorsiflexion, plantarflexion of ankle joint, maximum flexion of knee joint and hip joint with the increasing the angles of cutting movement(p<.05). Also, there were significant differences for the maximum adduction and abduction angle of the hip joint with the increasing of the angles of cutting movement. There was signigicant difference for the resultant utilized coefficient of friction(RuCOF) for the increasing angles of cutting movement(p<.05). Conclusion : There was a pattern to increase the coefficient friction with the angle of cutting direction. Also, it would be possible to use the poly urethane for the outdoor floor with the results of this study.

• Korean Journal of Applied Biomechanics
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• v.20 no.1
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• pp.33-39
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• 2010

The purpose of this study was to investigate the changes in walking pattern of the elderly during inclined walkway with uneven surfaces and level walking. 10 young($26.3{\pm}1.3$ years, $174.3{\pm}5.3\;cm$, $69.5{\pm}9.5\;kg$) and 13 elderly($72.4{\pm}5.2$ years, $164.5{\pm}5.4\;cm$, $66.1{\pm}9.6\;kg$) male subjects were participated in the experiment. Experiment consisted of 2 walking conditions: horizontal and inclined walkway with uneven surfaces. 3D motion capturing system were used to acquire and analyze walking motion data with sampling frequency of 120 Hz. To compare differences between conditions, kinematic variables(walking speed, stance-swing ratio, hip joint angle, knee joint angle, ankle joint angle, pelvic rotation angle) were used. Results showed that there were some changes of elderly walking pattern in inclined walkway with uneven surfaces: hip joint(adduction and rotation) and pelvic movement pattern. These changes by inclination and surface may affect gait pattern of young subjects as well as elderly subjects. However, in case of elderly it revealed more unstable gait than the young. Further study is necessary to clarify changes in walking pattern for elderly by considering various gait variables including head movement and various walkway conditions.

• Journal of Digital Convergence
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• v.13 no.7
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• pp.373-380
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• 2015

This study which was conducted on male tennis player on one hand(OH) & two hand(TH) backhand stroke and how both motion differed on low extremity movement with each feature analyzed in detail, the result as follow. The motion of TH based on resultant velocity, appeared to be a higher than OH, which was important variable in determining the ball speed. Contrary to TH where the player minimized the motion in the lower body and finalized a stroke through the turn of the trunk as if sticking the ball closed to the body, OH was carried out such that the player appeared to chase the ball. Whereas in OH, the knee joint extension moment was not found to be larger than TH, the opposite result came out for abduction moment and internal rotation moment. In the case of hip joint, consisted of extension, abduction and internal rotation moment, the outcome emerged to be greater for TH with conspicuous difference in abduction moment. Flection moment for TH overwhelmed in TH though both adduction and external rotation moment brought about similar outcome for both strokes.