• Journal of International Academy of Physical Therapy Research
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• v.11 no.4
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• pp.2203-2211
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• 2020

Background: Backpacks are one of the most widely used accessories in modern society. However, previous studies have shown that carrying a backpack can cause various musculoskeletal problems. Objectives: To investigate the effects of a body-adhesive backpack on craniovertebral angle, sagittal shoulder angle and the muscle fatigue in the upper extremity. Design: Randomized cross-over design. Methods: For this study, 36 healthy university students participated in this study. The experiment was conducted three times using common backpack, and body-adhesive backpack condition. The angles of the cervical spine and shoulder joints of the subjects were calculated without the backpack. Electrodes were placed at upper trapezius, lower trapezius, rectus abdominis and erector spinae to check for muscle fatigue. Subjects carried a backpack and walked on a treadmill for 15 minutes at 4 km/h. The muscle fatigue signal was also measured while walking. After walking, the craniovertebral and sagittal shoulder angles were measured again while subjects carried backpack. Results: As a result of this study, body-adhesive backpack condition showed significant decrease and significant increase in craniovertebral angle and sagittal shoulder angle than common backpack (P<.05). Body-adhesive backpack condition showed significant decrease in upper trapezius, lower trapezius, erector spinae, and rectus abdominis when compared to a common backpack (P<.05). Conclusion: This study suggests that a body-adhesive backpack is more beneficial in correcting body posture than a common backpack.

• Journal of the Korean Society of Physical Medicine
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• v.8 no.1
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• pp.41-48
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• 2013

PURPOSE: This study was to determine the effect of the plane of movement (sagittal plane vs. scapular plane) and shoulder flexion angle ($90^{\circ}$ vs. $130^{circ}$) during scapular protraction exercises in healthy subjects by investigating the elecromyographic (EMG) activities of the serratus anterior (SA), upper trapezius (UT), and pectoralis major (PM). METHODS: Twenty-one healthy subjects participated in this study. Subjects performed maximal scapular protraction at the $90^{\circ}$ or $130^{\circ}$ shoulder flexion angles in the sagittal or scapular planes. Surface EMG was recorded from the SA and UT, and PM muscles. Dependent variables were examined by 2 (plane) ${\times}$ 2 (angle) repeated measures of analysis of variance (ANOVA). RESULTS: Significantly increased EMG activities in the SA and UT were found during scapular protraction exercise at the $130^{\circ}$ shoulder flexion angle in the sagittal and scapular plane. Also, EMG activity of the PM significantly decreased at the $130^{\circ}$ shoulder flexion angle in the sagittal plane and the $90^{\circ}$ and $130^{\circ}$ shoulder flexion in the scapular plane. CONCLUSION: we recommend scapular protraction exercise at the $90^{\circ}$ shoulder flexion in the sagittal plane to selectively strengthen the SA muscle with limitation of upper trapezius activity and at the $130^{\circ}$ shoulder flexion in the scapular plane to selectively strengthen the SA muscle with limitation of pectoralis major activity.

• Journal of the Korean Society of Physical Medicine
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• v.11 no.4
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• pp.1-9
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• 2016

PURPOSE: The aim of this study was to examine the effects of abdominal breathing and thoracic expansion exercises on craniovertebral and cranial rotation angles in patients with rotator cuff injury. METHODS: This study enrolled 19 patients with rotator cuff injury, and ten and nine of the patients were randomly placed in abdominal breathing and thoracic expansion exercise groups, respectively. After pain treatment in each group, breathing exercise was conducted thrice a week for four weeks. The patients were recorded by using a digital camera and Image J (version 1.46, National Institutes of Health, USA), an angle measurement program, was used to analyze changes in the craniovertebral angle, cranial rotation angle, and sagittal shoulder posture. RESULTS: Statistically significant differences in the craniovertebral angle were found in both the abdominal breathing and thoracic expansion exercise groups (p<.05). A significant difference in cranial rotation angle was found in the thoracic expansion exercise group only (p<.05). No statistically significant differences in sagittal shoulder posture were found in both groups (p>.05). CONCLUSION: Although abdominal breathing and thoracic expansion exercises did not effectively change sagittal shoulder posture, the exercises were effective in improving craniovertebral and cranial rotation angles. Therefore, abdominal breathing and thoracic expansion exercises are suggested as effective exercise programs for forward head posture.

• Journal of radiological science and technology
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• v.45 no.5
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• pp.391-396
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• 2022

The purpose of this study was to investigate the effect of cross arms and palms facing forward on spinopelvic parameters during the whole spine lateral radiography. In addition, we would like to present the usefulness of a posture with the palm facing forward during whole spine lateral radiography of the spine using EOS. The subjects of this study were images of a total of 50 patients (18 males, 32 females) who whole spine lateral radiography using the conventional method and the EOS method from October 2020 to March 2021. The posture used in this study was set as 'CAP' for cross arms and 'PUSH' for posture with palms facing forward. In this study, among the spinal stability factors, thoracic kyphosis (thoracic vertebrae 4 to 12), lumbar lordosis (lumbar vertebrae 1 to sacrum 1), sagittal vertical axis, sacral slope, and shoulder flexion angle were compared on average. The mean thoracic kyphosis was 34.52±12.46° for CAP and 28.46±10.81° for PUSH (p<0.01). The lumbar lordosis of CAP was 42.45±17.45°and that of PUSH was 40.56±16.14°(p>0.57). The sagittal vertical axis was 26.59±34.34 mm in CAP and 21.21±35.41 mm in PUSH (p>0.44). In CAP, the sacral slope was 30.96±10.29°, and in PUSH, it was 31.01±10.19° (p>0.98). shoulder flexion angle was 38.31±8.24° for CAP and 26,08±6.71° for PUSH(p<0.01). As a result of this study, the PUSH posture is considered to be a posture that can minimize the shoulder flexion angle and can perform a stable examination while minimizing changes in spino-pelvic parameter.

• Clinics in Shoulder and Elbow
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• v.26 no.2
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• pp.148-155
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• 2023

Background: Although visual examination and palpation are used to assess shoulder motion in clinical practice, there is no consensus on shoulder motion under dynamic and static conditions. This study aimed to compare shoulder joint motion under dynamic and static conditions. Methods: The dominant arm of 14 healthy adult males was investigated. Electromagnetic sensors attached to the scapular, thorax, and humerus were used to measure three-dimensional shoulder joint motion under dynamic and static elevation conditions and compare scapular upward rotation and glenohumeral joint elevation in different elevation planes and angles. Results: At 120° of elevation in the scapular and coronal planes, the scapular upward rotation angle was higher in the static condition and the glenohumeral joint elevation angle was higher in the dynamic condition (P<0.05). In scapular plane and coronal plane elevation 90°-120°, the angular change in scapular upward rotation was higher in the static condition and the angular change in scapulohumeral joint elevation was higher in the dynamic condition (P<0.05). No differences were found in shoulder joint motion in the sagittal plane elevation between the dynamic and static conditions. No interaction effects were found between elevation condition and elevation angle in all elevation planes. Conclusions: Differences in shoulder joint motion should be noted when assessing shoulder joint motion in different dynamic and static conditions.

• International Journal of Safety
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• v.4 no.1
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• pp.27-31
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• 2005

This study presents the relationship between the height of the chair and the force of deltoid muscle for pianist. The subject simulated playing the piano on the three different heights of the chairs. Digital camera was used to determine the angle of the joint of shoulder and elbow for 2-dimensional static link segment modeling in the sagittal plane. The deltoid, biceps and triceps muscles were considered to determine the muscle load. The results, compared to the force of deltoid muscle, are that the downward position of the higher chair produces significantly large force than the other two lower chairs. It can be caused by hunched shoulder with decreasing deltoid angle. In case of the upward position caused by the lower chair, even though the smallest force of deltoid presented, it was increased the force of elbow.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.12
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• pp.1121-1127
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• 2013

This study deals with experimental studies on electromyogram (EMG) measurements and functional electrical stimulation (FES) for the rehabilitation of a shoulder-joint. Based on the structure, motion, and main functions of the musculoskeletal system in a shoulder-joint, the muscles playing a major role for the motion in the sagittal plane were selected for the experiment. First, the surface electromyogram of the main muscles was measured according to the joint angle. The results showed that the change in the surface EMG was linearly proportional to the change in the joint angle. Second, the joint angle was measured during FES at shoulder muscles. The results showed that the joint angle increased as the FES current increased in a certain range of FES. It was confirmed that the willingness of muscles to move could be detected by measuring EMG and that the generation of muscle tension could be assisted by FES for active rehabilitation.

• PNF and Movement
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• v.17 no.2
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• pp.207-214
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• 2019

Purpose: Although multi-directional reaching exercises are commonly used clinically, the effects of specific movement directions on the muscle systems of the lower extremities have not been explored. We therefore investigated lower extremity muscle activity during reaching exercises with different sagittal and horizontal plane movements. Methods: The surface electromyography responses of the bilateral rectus femoris, tibialis anterior, peroneus longus, and gastrocnemius muscles were measured during reaching exercises in three directions in the horizontal plane (neutral, $45^{\circ}$ horizontal shoulder adduction, and $45^{\circ}$ abduction) and three directions in the sagittal plane (neutral, $120^{\circ}$ flexion, and $60^{\circ}$ flexion). A total of 20 healthy, physically active participants completed six sets of reaching exercises. Two-way repeated ANOVA was performed: body side (ipsilateral and contralateral) was set as the intra-subject factor and direction of reach as the inter-subject factor. Results: Reaching at $45^{\circ}$ horizontal shoulder adduction significantly increased the activity of the contralateral rectus femoris and gastrocnemius muscles, while $45^{\circ}$ horizontal shoulder abduction activated the ipsilateral rectus femoris and gastrocnemius muscles. The rectus femoris activity was significantly higher with reaching at a $120^{\circ}$ shoulder flexion compared to the other conditions. The gastrocnemius activity decreased significantly as the shoulder elevation angle increased from $60^{\circ}$ to $120^{\circ}$. Conclusion: Our results suggest that multi-directional reaching stimulates the lower extremity muscles depending on the movement direction. The muscles acting on two different joints responded to the changes in reaching direction, whereas the muscles acting on one joint were not activated with changes in reaching direction.

• Clinics in Shoulder and Elbow
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• v.1 no.2
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• pp.250-255
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• 1998

Purpose of the study was to analyze the supraspinatus outlet image of sagittal MRI in rotator cuff disease. We analyzed the sagittal views of the shoulder MRI of 78 cases without cuff tear. The cases were divided into 51 cases of rotator cuff disease group and 27 cases of control group. Six parameters of acromial tilt, coracoacromial ligament angle, length and height of coracoacromial triangle, length of acromial side of the baseline and distance of intrusion of the humeral head were compared for each group. The distance of intrusion of the humeral head was the most significantly different one, 0.52cm for rotator cuff disease group and 0.15cm for control group. Intrusion of the humeral head to the supraspinatus outlet space from the bottom may be a contributing factor developing rotator cuff disease. The intrusion may precede to tearing of the rotator cuff.

• Journal of the Ergonomics Society of Korea
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• v.25 no.2
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• pp.11-22
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• 2006

The muscular-skeletal disorders(MSDs) that have become a major issue recently in Korean industrial safety area are mainly caused by manual material handling task. The objective of this study is to provide scientific data for the establishment of work safety standard for Korean workers through the experiments of lifting task under various conditions, in order to prevent the muscular-skeletal disorders in the industrial work site. Eight male college students were recruited as participants. Three different lifting frequencies(1, 3, 5 lifts/min) and three twisting angles(including the sagittal plane and two asymmetric angles; i.e., 0°, 45°, 90°) for symmetric and asymmetric tasks, respectively, with three lifting range from floor to knuckle height, knuckle to shoulder, floor to shoulder height for one hour's work shift using free style lifting technique were studied. The maximum acceptable weight of load(MAWL) was determined under the different task conditions, and the oxygen consumption, heart rate, and RPE were measured or recorded while subjects were lifting their MAWLs. The results showed that: (1) The MAWLs were significantly decreased as the task frequency and task angle increased.; (2) The heart rate, oxygen consumption, RPE significantly increased with an increase in lifting frequency although maximum acceptable weight of lift decreased.; (3) The highest heart rate and oxygen consumption was recorded at the lifting range of floor to shoulder, followed by floor to knuckle and knuckle to shoulder.; (4) The RPE value showed that subjects perceived more exertion at the high frequency rate of lifting task and lifting range of floor to shoulder height. (5) The modeling for MAWL using isometric strength, task angle and lifting frequency were developed. It is expected that use of the results provided in this study may prove helpful in reducing MMH hazards, especially from lifting tasks for Korean, and can be used as a basis for pre-employment screening.