• Journal of The Korean Society of Integrative Medicine
• /
• v.3 no.1
• /
• pp.81-90
• /
• 2015

Purpose: The purpose of this study was to investigate any visible difference in shoulder stability muscle activity along the bending angle($70^{\circ}$, $90^{\circ}$, $110^{\circ}$) to perform the open kinetic chain(OKC) and closed kinetic chain(CKC) exercise. Method: This study was performed on normal 20 males subjects. Exercise was carried out in two ways OKC and CKC. Shoulder stability muscles are examined activity in the bending angles. In the OKC and CKC exercise to subjects with stretched out waist straightened, and than push forward the shoulder. Muscular activation was examined using the WEMG-8. Result: The results of this study were as follows. 1. Only in the trapezius muscle, it showed specific interaction between exercise methods and angles. When it comes to muscle activity, there was no significant difference in all muscles except for the anterior fibers of the deltoid muscle during both CKC and OKC exercise. 2. The average value of maximum muscle activity was significantly increased with increasing order of angles. But in CKC exercise, the muscle activity of infraspinatus tended to decrease with increasing angles. Conclusion: To summarize the research results, the muscle activity in upper fibers of the trapezius, anterior fibers of the deltoid, and serratus anterior was significantly different depending on the angle of the shoulder in both CKC and OKC exercise.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.35 no.11
• /
• pp.1461-1469
• /
• 2011

Using three-dimensional (3-D) FE analyses, this paper provides a method for analyzing the effects on stresses and strains produced by angular and concentric misalignment of a test specimen for a torsion test. To quantitativele compare of the FE results, the average bending strain for the angular, concentric, and combined misalignment was proposed. To verify the effects of axial misalignment of the test specimens, we used both circular and tubular specimens. From the FE results, we proposed general predictions for the effects caused by the various types of axial misalignment and its direction. In addition, we confirmed the effect of initial yielding moment based on the initial yielding condition for axial misalignment of specimens in torsion tests.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.43 no.10
• /
• pp.888-895
• /
• 2015

This paper shows an approximate equation which calculates a flapping angle of blade for verification of KUH safety area. The flapping behavior of blade must be reviewed in an aspect of safety because of a collision possibility with airframe. However, it is difficult to measure an exact flapping angle during flight. A prediction equation of a coning angle is derived from aeromechanics and that of a dynamic flapping angle is derived from analysis results in development phase, respectively. Following, the equations are verified by comparison the flapping angle through an aircraft simulation test to a calculation. Finally, the safety area, which was established in development phase, is verified by calculating a flapping angle during the flight which is required by the terms of safety based on AC29 and FAR29.

• PNF and Movement
• /
• v.18 no.1
• /
• pp.127-132
• /
• 2020

Purpose: This study aimed to investigate the impact of resistance on the muscle activities of the long and short heads of the biceps brachii, according to the elbow angle in supination, and the difference in muscle activity between the long and the short heads. Methods: This study was conducted with 22 men in their 20s who voluntarily agreed to participate. With the glenohumeral joint neutral in a position of supination, the elbow angle was randomly moved to 0°, 30°, 60°, and 90°. Using an 8-channel surface EMG while the participants held a 2-kg. dumbbell, the muscle activities of the long and the short heads of the biceps brachii were measured. The measured data were statistically processed using SPSS for Windows 12.0. For the activities of the short and the long heads according to the angle, a one-way ANOVA was conducted, and subsequently, to check the results of an analysis of the difference between groups, an LSD post-hoc test was conducted. An independent t-test was used to compare the activities of the long head and the short head according to the angles. Results: The analysis of the impact of the load of the dumbbell at each elbow angle on the muscle activities of the long and short heads of the biceps brachii revealed significant differences in both heads (p < 0.05). The result of the post-hoc analysis showed significant differences in both heads at angles between 0° and 30°, between 0° and 60°, and between 0° and 90°. Analysis of the impact of the load of the dumbbell in supination on the muscle activities of the long and short heads showed a significant difference at the angle between 0° and 30° (p < 0.05). Conclusion: The long head of the biceps brachii mainly acts in supination; however, in supination at elbow-bending angles of 60° and 90°, there was no difference in muscle activity between the short head and the long head.

• Journal of Digital Convergence
• /
• v.17 no.3
• /
• pp.463-471
• /
• 2019

The purpose of this study was to investigate the effect of muscle imbalance on motion of back squat. The isokinetic muscle strength of the 8 subjects was recorded for the knee flexion/extension by the cybex 770 dynamometer. Each subject performed 3 back squats with the long barbell with an intensity of 25% body weight(BW), 50%BW, 100%BW, 125%BW. During the back squat through the recorded kinematic data the subjects' maximum flexion and extension knee angle, center of mass displacement and V-COP were calculated for evaluation of the stability of the movement. For the statistical analysis independent t-test was used. Knee flexion angle and COM displacement are dominated by the reciprocal muscle ratio. V-COP factor was dominated by bilateral extension deficit. Based on the results we can know that as the intensity of the squat increased to a level control was difficult because the muscles' imbalance influenced the movement.

• Journal of the Korean Society of Physical Medicine
• /
• v.14 no.2
• /
• pp.137-144
• /
• 2019

PURPOSE: The continued use of smartphones has resulted in an abnormal body posture and neck alignment changes. Maintaining this posture for a long time weakens the flexor muscles in the neck and shortens the extensor muscles in the neck. This study examined the correlation between the suboccipital muscle tension and deep neck flexor muscle physical endurance according to the craniovertebral angles. METHODS: The craniovertebral angle, tension of the suboccipital muscle and endurance of the deep neck flexor muscle were measured in 58 healthy 20-year-old male and female college students. The tension of suboccipital muscle and endurance of the deep neck flexor muscle were then divided according to the body mass index (BMI). Their correlation with the craniovertebral angle was then examined. Each parameter was measured three times to determine the interrater reliability. RESULTS: The craniovertebral angle and suboccipital muscle tension showed differed significantly. On the other hand, the craniovertebral angle and deep neck flexor muscle physical endurance showed no significant differences. CONCLUSION: The results show that the craniovertebral angle and deep neck flexor muscle physical endurance were not correlated, but a smaller craniovertebral angle resulted in a higher suboccipital muscle tension.

• PNF and Movement
• /
• v.19 no.1
• /
• pp.147-152
• /
• 2021

Purpose: This study was conducted to investigate the functional differences of the two heads of the biceps brachii by measuring the functions in supination according to pronation by the angle of the flexion of the elbow joint, except for the activities of the elbow flexors. Methods: This study was conducted with 25 healthy men in their 20s. At a glenohumeral-joint 0˚ flexion posture, angles of flexion of the elbow joint of 0˚, 30˚, 60˚, 90˚, and 120˚ were randomly provided, and they were asked to perform supination and pronation with an elastic band. Using an eight-channel surface electromyogram, the muscle activities of the long and short heads of the biceps brachii were measured. The activities of the short and long heads according to the angle were analyzed using a one-way ANOVA, and as a post-test, LSD was employed. Results: The analysis of the impact of the resistance of the elastic band in supination on the differences in the muscle activities in the short and long heads suggests there was a significant difference between 0˚ and 30˚ (p < 0.05). Conclusion: In supination according to forearm pronation, the long head had greater action in the early flexion posture of the elbow joint, and it is judged that the ratio of the flexion of the elbow joint according to the actions of the biceps brachii was considered small.

• Journal of Korean Physical Therapy Science
• /
• v.30 no.3
• /
• pp.23-30
• /
• 2023

Background: Flexion of cervical and lumbar joints is required when viewing a smartphone screen. Thus, these joints are overused, together with the surrounding joints and muscles. Long-term use of smartphones will cause changes in cervical and lumbar posture. The effect on forward head posture will vary, depending on the angle of cervical flexion start position in relation to the smartphone. This study investigated how forward head posture changes over time when using a smartphone at 20° and 40° cervical flexion start positions. Design: Cross-sectional study. Methods: Twenty-five subjects with a forward head posture angle of 35° or less participated in the study. A Forward Head Posture app on the participants' smartphones measured forward head posture 5 and 10 minutes after watching videos on their smartphones. Cervical range of motion was used to set a smartphone watching start posture of 20° and 40° of cervical flexion. Results: There was no significant difference in forward head posture, irrespective of cervical flexion start position, but the angle of forward head posture increased more at cervical flexion of 40° than at cervical flexion of 20°. There was no significant difference in what according to smartphone video viewing times, but the angle of forward head posture increased over time. Conclusion: An increase in forward head posture over time with smartphone usage poses a potential risk of neck and shoulder pain. Therefore, smartphone users should avoid prolonged screen time.

• Science of Emotion and Sensibility
• /
• v.20 no.3
• /
• pp.141-150
• /
• 2017

The purpose of this study was to analyze the effect of the shape and attached position of E-textile-based stretchable sensors on motion-sensing performance and to investigate the requirements for the optimal structure of clothes for sensing limb motions. An experimental garment was prepared with different sensor shapes, and attachment positions. A child subject, wearing the experimental garment, performed arm and leg bending and extension motions at $60^{\circ}$, $90^{\circ}$ and $120^{\circ}$ motion angles, at a rate of 60 deg/sec. The changes in voltage triggered by the stretching and contracting of the fabric-sensor were measured, and an acceleration sensor was utilized to verify that the experimental motions were correctly performed. Dummy arms and legs of a child were manufactured to perform an identical test, in order to compare the dummy results with the actual human body experiment results. The analysis showed that the reproducibility and reliability of the rectangular sensor, showing uniform and stable were higher than those of the boat-shaped sensor, in both the dummy and the human body experiments. The attachment position of the sensor was more reproducible and reliable when placed on 4 cm below the elbow and knee joints in the dummy test, when placed in the joints of the elbow and knee, in children experiment. The appropriate shapes and attached positions of the sensor for sensing the motions were analyzed, and the results proved that motion-sensing of the human body is possible by utilizing flexible fabric-sensors integrated into clothes.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.10
• /
• pp.313-323
• /
• 2018

This study was conducted to develop an individualized upper extremity exercise program for patients after mastectomy and evaluate its effectiveness. A nonequivalent control-group pretest-posttest design was used for this investigation. Research participants were patients with breast cancer who underwent mastectomy at two university hospitals (experimental group, n=17; control group, n=16). The experimental group received an individualized upper extremity exercise program three times a week for 7 weeks. Data were analyzed by the ${\chi}^2-test$, Fisher's exact test, Mann-Whitney U-test and Wilcoxon Signed Rank test using SPSS WIN 21.0. Inter-group comparison revealed significant differences between pre-test and post-test in hands behind the back, flexion, abduction, external rotation, internal rotation, and grip strength. Moreover, the experimental group showed significant improvements in hands behind the back, flexion, abduction, external rotation, internal rotation, and grip strength relative to the control. In conclusion, the individualized upper extremity exercise program was shown to be an effective intervention to improve physical functions in upper limbs and shoulders. Therefore, this program should be applied to patients after mastectomy in clinics since many patients have suffered from decreased physical functions in upper extremities.