• Korean Journal of Applied Biomechanics
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• v.15 no.4
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• pp.85-95
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• 2005

The purpose of this study was to investigate the relations between the segments of the body, the three dimensional anatomical angle during One Hand Backhand Stroke and Two Hand Backhand 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 LabVIEW 6.1 graphical programming(Johnson, 1999) program. By using Eular's equations the three dimensional anatomical Cardan angles of the joint and racket head direction were defined. 1. In three dimensional maximum linear velocity of racket head the X axis and Y axis(horizontal direction) showed $-11.04{\pm}2.69m/sec$, $-9.31{\pm}0.49m/sec$ before impact, 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 $75.4{\pm}5.86cm$ during one hand backhand stroke and $72.6{\pm}4.67cm$ during two hand backhand stroke. 2. The three dimensional anatomical angular displacement of trunk in interna rotation-external rotation showed most important role in backhand stroke. and is follwed by flexion-extension. the three dimensional anatomical angular displacement of trunk did not show significant difference between one hand backhand stroke and two hand backhand stroke but the three dimensional anatomical angular displacement of trunk was bigger than one hand backhand stroke. 3. while backhand stroke, the flexion-extension and adduction-abduction of right shoulder joint showed significant different between one hand backhand stroke and two hand backhand stroke. the three dimensional anatomical angular displacement of right shoulder joint showed more flex and abduct in one hand backhand stroke. 4. The three dimensional anatomical angular displacement of left shoulder showed flexion, adduction, and external rotation at impact. after impact, The angular displacement as adduction-abduction of left shoulder changed motion direction as abduction. angular displacement of left shoulder as flexion-extension showed bigger than the right shoulder.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.8
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• pp.505-510
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• 2017

This paper presents a low-cost robotic device for shoulder rehabilitation, which is capable of treating various shoulder disabilities. A 3-DOF passive shoulder joint tracking module was designed to allow for translational motion of the shoulder joint center during arm swing, which is essential for natural shoulder movement. The weight of the user's arm and the device were compensated for by springs, to enable gravity-free shoulder motion. In order to reduce the device's cost, only one actuator was used, which can be aligned with the user's shoulder joint in various orientations. The device is capable of implementing five representative shoulder motions, including flexion/extension, abduction/adduction, horizontal abd/adduction, internal/external rotation, and oblique raise. The proposed low-cost shoulder rehabilitation robot is expected to provide effective rehabilitation for patients with various shoulder impairments.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.22 no.2
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• pp.15-20
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• 2016

Background: The purpose of this study was to compared of scapular position between operation side and non-operation side to the rotator cuff surgery. Methods: This study was carried out with a total 34 patients: male (n=14), female (n=20). Shoulder range of motion (ROM), the quadruple visual analogue scale (QVAS), the shoulder pain and disability index (SPADI), and the scapular index (SI) were used to assess shoulder posture and function. SI was the resting position of the scapular was determined by measuring the distance from the mid-point of the sternal notch (SN) to the medial aspect of the coracoid process (CP) and the horizontal distance from the posterolateral angle of the acromion (PLA) to the thoracic spine (TS) with a soft tape measure. The SI was calculated using the equation: [(SN to CP/PLA to TS) ${\times}$ 100]. Results: There were no significant difference in ROM, QVAS to rotator repair patients according to SI (p>.05). There were significant differences in SI between the operation side and the non-operation side (p<.01). Conclusions: Scapular position was operation side more internal rotation, protraction, abduction than non-operation side. Therefore, health professionals managing for rotator cuff tear repair patients should consider scapular position.

• Journal of Korean Orthopaedic Sports Medicine
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• v.4 no.1
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• pp.36-42
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• 2005

Purpose: To investigate the arthroscopic findings, and to evaluate the clinical outcomes of the treatment of posterior internal impingement of the shoulder in baseball players. Materials and Methods: We followed up 5 cases who were diagnosed as posterior internal impingement for the mean 15 months. All of the cases complained of the pain in the posterior shoulder at late cocking, and were positive in the relocation test added by hyper-horizontal abduction at $120^{\circ}$ abduction of the arm. We sutured posterior labral tear and SLAP lesion arthroscopically, and conducted debridement for rotator cuff. Three cases were performed of anterior capsular plication and the other two were performed of thermal capsular shrinkage. Pain, range of motion, and level of return to sports activity were assessed for the results. Results: As to the arthroscopic findings, all the five cases showed the fraying in posterosuperior labrum, and two of them was accompanied with the flap tear in posterosuperior labrum and the other one was accompanied with type 2 SLAP lesion. All the cases showed the fraying in supraspinatus, and one case showed partial tear. Meanwhile, in all the cases, the rotator cuff was impinged to the labrum at $90^{\circ}{\sim}120^{\circ}$ of abduction and external rotation. As to the postoperative results, all the cases did not complain of pain or instability while pitching, and the competition was recovered to be the mean 88%($80{\sim}100%$) of that before the injury. Conclusion: Definite diagnosis for the posterior internal impingement would be possible through arthroscopic examination. Favorable outcomes could be obtained with capsular plication or shrinkage for anterior microinstability and stretching exercise for posterior capsule tightness inducing the internal impingement.

• PNF and Movement
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• v.18 no.1
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• pp.107-116
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• 2020

Purpose: To investigate the effects of electromyography (EMG) biofeedback on the muscle activity of the trapezius, shoulder pain, function, and range of motion (ROM) in patients with subacromial impingement syndrome (SAIS). Methods: Sixteen patients (9 males and 7 females) with SAIS participated voluntarily. The main outcome measures were muscle activity of the trapezius, shoulder pain (VAS), ROM, and the shoulder pain and disability index (SPADI). Exercises with EMG biofeedback consisted of shoulder flexion in a standing position, shoulder external rotation in a side-lying position, and shoulder horizontal abduction in a prone position. Post measurements were taken immediately after EMG biofeedback training. Results: Middle and lower trapezius activity, as well as ROM, was significantly increased by exercise with EMG biofeedback (p<0.05). In addition, VAS and SPADI scores significantly decreased post-EMG biofeedback training (p<0.05). Conclusion: EMG biofeedback intervention is an effective exercise for SAIS patients to restore activity of the middle and lower trapezius and to improve pain, shoulder function, and ROM.

• The Journal of Korean Physical Therapy
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• v.31 no.4
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• pp.199-203
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• 2019

Purpose: This study investigated the effects of shoulder protraction exercise according to weight by examining the surface electromyography (EMG) amplitude in the serratus anterior (SA), upper trapezius (UT), and pectoralis major (PM) as well as the activity ratio of each muscle. Methods: Twenty three winging scapula subjects participated in the study. The subjects performed scapula protraction at shoulder $90^{\circ}$ flexion and $60^{\circ}$ horizontal abduction with up to four (none, 1kg, 1.5kg, and 2kg) dumbbells in the supine position. The EMG data were collected from the dominant side muscles during a shoulder protraction exercise according to weight in the supine position. One way repeated measures analysis of variance (ANOVA) was used to compare the normalized activities of the SA, UT, and PM and the ratios of PM/SA and UT/SA. Results: The results showed that the activities of both the SA and UT were highest for the shoulder protraction exercise at 2kg in the supine position. The UT/SA ratio also was the lowest for exercise at 2kg. On the other hand, the activities of both the UT and PM/SA ratio were similar under all conditions. Conclusion: These results show that there is a need to selectively strengthen the SA muscle in the case of patients with the shoulder dysfunction. In particular, it is necessary to weigh 2kg when performing shoulder protraction exercises in the supine position to activate the SA muscle in patients with a winging scapula.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.14 no.2
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• pp.25-33
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• 2008

Purpose : This study was investigated the effect on grasp and pinch strength according to degree of flexion in elbow joint. Methods : Thirty male and thirty female students, aged 20 to 31 years were tested for using opened positioning with their shoulder abduction at $55^{\circ}$ and shoulder horizontal adduction at $30^{\circ}$ in four elbow flexion($0^{\circ}$, $45^{\circ}$, $90^{\circ}$, $135^{\circ}$). An electronic dynamometer(E-LINK V900s Evaluation System)and goniometer were used to measure grasp and pinch strength. Results : The average grasp strength of the dominant hand was strongest at elbow $45^{\circ}$ however, weakest at elbow $135^{\circ}$ flexion in both of male and female. The average pinch strength of the dominant hand was strongest at elbow $135^{\circ}$ flexion in both of male and female. The average pinch strength of dominant hand was weakest at elbow $45^{\circ}$ flexion in both of male and female. According to degree of elbow flexion in both of male and female, grasp and pinch strength was no significant statistically. In analyzing correlations, the grasp strength of male showed the most significant difference at elbow $45^{\circ}$ & $90^{\circ}$ flexion, and the pinch strength was most significant difference at elbow $0^{\circ}$ & $45^{\circ}$ flexion. Conclusion : In analyzing correlations, the grasp strength of female showed the most significant difference at elbow $90^{\circ}$ & $135^{\circ}$ flexion, and the pinch strength was most significant difference at elbow $45^{\circ}$ & $90^{\circ}$ flexion.

• Journal of the Korean Society of Physical Medicine
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• v.13 no.4
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• pp.85-94
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• 2018

PURPOSE: This study was conducted to determine the effects of therapeutic exercise on range of motion (ROM), the manual muscle test (MMT), functional movement screen (FMS) and radiological evaluation in a youth football player with football-specific anterior pelvic tilt (APT). METHODS: The subject of this case report was a 12-year-old youth football player, who presented with football-specific APT. Therapeutic exercise consisted of hamstring stretch, prone hip extension, abdominal crunch, bridging with isometric hip abduction, plank exercise with posterior tilt and posterior pelvic tilting exercise using a swiss-ball for 40 min/day, twice a week for 8-weeks. ROM, MMT, FMS (deep squat, hurdle step, inline lunge, shoulder mobility, active straight-leg raise, rotary stability and trunk stability push-up) and radiographs (lumbar lordotic and sacral horizontal angle) were analyzed before and after week 8 of therapeutic exercise. RESULTS: The ROM, MMT, and FMS increased and the lumbar lordotic angle and sacral horizontal angle improved after 8-weeks of therapeutic exercise. CONCLUSION: The results of this case report suggest that therapeutic exercise improves ROM, MMT and radiography associated parameters in youth football players with football-specific APT. These findings have clinical implications for therapeutic exercise in youth football players with football-specific APT.

• 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.16 no.4
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• pp.49-59
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• 2006

The purpose of this study was to investigate the relations between the segments of the body, the three dimensional anatomical angle according to sweep shot in ice hockey. The subjects of this study were five professional ice hockey players. The reflective makers were attached on anatomical boundary line of body. 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 LabVIEW 6.1 graphical programming(Johnson, 1999) program. By using Eular's equations the three dimensional anatomical Cardan angles of the joint and ice hockey stick were defined. 1. In three dimensional linear velocity of blade the Y axis showed maximum linear velocity almost impact, the X axis(horizontal direction) and the Z axis(vertical direction) maximum linear velocity of blade did not show at impact but after impact this will resulted influence upon hitting puck. 2. The resultant linear velocity of each segment of right arm showed maximum resultant linear velocity at impact. It could be suggest that the right arm swing patterns is kind of push-like movement. therefore the upper arm is the most important role in the right arm swing. 3. The three dimensional anatomical angular displacement of trunk in flexion-extension showed flexion all around the wrist shot. The angular displacement of trunk in internal-external rotation showed internal rotation angle at the backswing top and and increased the angle after the impact. while there is no significant adduction-abduction. 4. The three dimensional anatomical angular displacement of trunk showed most important role in wrist shot. and is follwed by shoulder joints, in addition the movement of elbow/wrist joints showed least to the shot. this study result showed upperlimb of left is more important role than upperlimb of right.