• Coupled systems mechanics
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• v.4 no.1
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• pp.99-114
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• 2015

In this paper, a refined exponential shear deformation beam theory is developed for bending analysis of functionally graded beams. The theory account for parabolic variation of transverse shear strain through the depth of the beam and satisfies the zero traction boundary conditions on the surfaces of the beam without using shear correction factors. Contrary to the others refined theories elaborated, where the stretching effect is neglected, in the current investigation this so-called "stretching effect" is taken into consideration. The material properties of the functionally graded beam are assumed to vary according to power law distribution of the volume fraction of the constituents. Based on the present shear deformation beam theory, the equations of motion are derived from Hamilton's principle. Analytical solutions for static are obtained. Numerical examples are presented to verify the accuracy of the present theory.

• Journal of the Korea Society of Computer and Information
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• v.25 no.1
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• pp.125-130
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• 2020

This study is to investigate the effects of stretching of hospital office employees on muscle stiffness. A total of 40 healthy young women voluntarily participated in the study. The participants were randomized to the stretching groups and control groups. Before stretching, the participants measured muscle stiffness of sternocleidomastoid muscle, upper trapezius muscle suboccipital muscles and pectoralis minor. And then applied stretching to stretching group. Muscle stiffness remeasured five minutes later in each group. In all muscles, muscle stiffness of stretching group were significant decreased(p<.05), but control group were no significant difference between pre and post. therefore appropriate stretching is expected to prevent and reduce musculoskeletal diseases caused by increased muscle stiffness in hospital office employees.

• Korean Journal of Applied Biomechanics
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• v.18 no.4
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• pp.41-47
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• 2008

The purpose of this study was to provide foundations for proper stretching method not to lose muscle strength caused by shrink of muscle for preventing injury and improving performance when we make training programs. This study compared and analyzed isokinetic variables related to the static stretching frequency of knee joint extensor by isokinetic instruments applied to normal adults. 45 normal adults are randomly sampled into 3 different groups. All the measured variables were processed with SPSS and, means and standard deviations at each angle speed were calculated. The difference of means between before and after stretching of each groups were processed by paired t-test. One-way ANOVA and after test(Duncan) This study was able to see that stretching decrease acute isokinetic muscle strength High frequency stretching group showed more efficient decrease of muscle strength than low frequency stretching group. As a result, making training program for a game requiring strong muscle strength should consider proper stretching method not to lose muscle strength.

• The Journal of Korean Physical Therapy
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• v.31 no.5
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• pp.266-272
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• 2019

Purpose: This study compared the effects of Static stretching and Mulligan's Two-leg rotation about the Hamstring flexibility, Hip range of motion, and pain. Methods: The subjects were allocated randomly into two groups: Static stretching group (n=13) and Mulligan's two leg rotation group (n=14). The study was designed with stretching protocols for four minutes and thirty seconds per day five times a week for three weeks in total. Measurements, including the Sit and reach test, Active/Passive Straight leg raise, and Visual analogue scale, were conducted before and after the intervention. The data were analyzed using a paired t-test and independent t-test. Results: The flexibility of the two leg rotation group was higher than the static stretching group after the intervention. The post-sit and reach test value of the two leg rotation group was significantly higher than the pre-sit and reach test value of the static stretching group. In addition, the variance of the sit and reach test of the two leg rotation group was significantly higher than that of the static stretching group. Conclusion: These results showed that two leg rotation techniques have a positive effect on the changes in the sit and reach test and active straight leg raise test. Two leg rotation techniques can be recommended as a self-stretching and easier way to stabilize the lumbopelvic rhythm, reduce the stiffness of the muscle and relieve pain. This is effective in preventing muscle damage, enabling muscle relaxation and reducing the risk of injury to the spine during daily lives and in sports activities.

• Journal of Korea Entertainment Industry Association
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• v.13 no.1
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• pp.225-233
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• 2019

The study was to find out the effects of computer game and stretching on muscle tone and concentration. The subjects were 30 adults, who were divided into 15 stretching group and 15 control group after applying computer game for 120 minutes. The subjects measured muscle tone and concentration before experiment, the same measurements were made before and after applying the stretching. The muscle tone was respectively measured after 60 minutes and 120 minutes of computer game. The results showed that muscle tone increased significantly after 60 minutes and 120 minutes of computer game, and significantly decreased in the stretching intervention group. Concentration increased significantly after computer game, but there was no significant difference after application of stretching. In this study, computer game increased muscle tone and concentration, and stretching decreased increased muscle tone. Therefore, proper stretching after computer games will reduce musculoskeletal diseases caused by increased muscle tone, and development of appropriate game contents will be an effective tool for concentration training.

• The Journal of Korean Physical Therapy
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• v.31 no.1
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• pp.56-61
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• 2019

Purpose: The spasticity of stroke patients decreases the ankle range of motion and increases the gastrocnemius muscle tone. This study examined the effects of stretching exercise and far infrared irradiation on the ankle function in stroke patients with spasticity. Methods: This study was conducted on 20 stroke patients admitted to Jesaeng General Hospital, who were divided into a study group (stretching exercise with far infrared) and control group (stretching exercise only). The dorsiflexion range of motion was measured using a smartphone and the medial gastrocnemius muscle tone and stiffness were measured using a Myoton pro. Results: With the exception of the non-paretic gastrocnemius muscle tone in the control group, the medial gastrocnemius muscle tone and stiffness decreased significantly in both groups. In both groups, the dorsiflexion range of motion increased significantly. In addition, the experimental group had a significantly higher dorsiflexion range of motion than the control group. On the other hand, there was no significant difference between the two groups in terms of the medial gastrocnemius muscle tone and stiffness. Conclusion: For stroke patients with spasticity, stretching exercises increased the ankle's range of motion and decreased the gastrocnemius muscle tone. The addition of heat therapy further increased the ankle's range of motion. On the other hand, as the sample size was small, future studies should include more subjects.

• Journal of International Academy of Physical Therapy Research
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• v.9 no.4
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• pp.1614-1618
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• 2018

The purpose of this study was to evaluate the effect of joint mobilization and manual stretching exercises in patients with hallux valgus. Twenty-three participants were divided into two groups; joint mobilization (n=11) and manual stretching exercises (n=12). The subjects participated in the experiment for 15minutes, three times a week, four weeks. The joint mobilization (Grade III, Maitland) was performed to experimental group for a minute and then rested for 10 seconds for each set. The manual stretching was performed to control group with three exercise session (preparatory and finishing exercises, agonist contraction exercises, agonist contraction and hold-relax exercises). In the results of the study, intragroup comparison of the deformity angles (DA) was shown to decrease from $15.18^{\circ}$ to $13.09^{\circ}$ in the joint mobilization group (p<.05) and from $19.00^{\circ}$ to $16.83^{\circ}$ in the stretching exercises group (p<.05). However, left static foot pressure (LSFP), right static foot pressure (RSFP), left dynamic foot pressure (LDFP) and right dynamic foot pressure (RDFP) did not significantly increase or decrease after the experiment. Intergroup differences also were not statistically significant in all variables (p>.05). The current study suggests that JM and MSE are effective in decreasing the DA in patients with hallux valgus.

• Physical Therapy Rehabilitation Science
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• v.10 no.2
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• pp.225-234
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• 2021

Objective: We aimed to identify the effects of proprioceptive neuromuscular facilitation (PNF) stretching on pain, hip range of motion, and functional disability in patients with chronic low back pain. Design: Randomized controlled trial Methods: In total, 45 patients with chronic low back pain were randomly divided into a conventional stretching group (n=22) and a PNF stretching group (n=23). Both interventions were performed three times per week for 6 weeks. Assessments were made using the visual analog scale, Flexion-Abduction-External Rotation test, modified Thomas test, prone hip extension test, and Oswestry disability index before and after the 6-week intervention period. We conducted a paired t-test to compare the within-group findings before and after the intervention. An independent t-test was used to compare the between-group differences. The statistical significance level was set at α=0.05, for all variables. Results: Both groups showed significant improvements in pain, hip range of motion, and functional disability after the intervention (p<0.05). A significant difference was observed in pain, hip range of motion, and functional disability in patients belonging to the PNF stretching group (p<0.05). Conclusions: This study provides evidence that the application of PNF stretching can effectively reduce pain and improve hip range of motion and functional disability in patients with chronic low back pain.

• Journal of the Korean Society of Physical Medicine
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• v.18 no.4
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• pp.97-107
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• 2023

PURPOSE: This study aimed to explore the effect of applying elastic taping and passive stretching exercises simultaneously on the muscle tone of the upper trapezius. METHODS: Thirty healthy adults were randomly divided into two groups: the 'passive stretching exercise' group (n = 15) and the 'passive stretching exercise with elastic taping' group (n = 15). Muscle tone was measured using the MyotonPRO®. The muscle tension was measured immediately after the stretching exercises and taping intervention, and again 5 minutes after the intervention. RESULTS: Within each group, there was a significant reduction in muscle tone in the upper trapezius after treatment (p < .05). However, there was no significant difference in the muscle tone reduction between the groups (p > .05). Both experimental and control groups showed a significant decrease in muscle tone in both the upper trapezius muscles over time, i.e., immediately after treatment and five minutes later (p < .05). The main effect of time was identified in the repeated measures analysis, while there was no main effect attributed to the treatment method (group) (p < .05). CONCLUSION: The simultaneous application of stretching exercises and taping as an intervention to reduce muscle tension in the upper trapezius is still considered challenging and not yet widely regarded as an essential intervention method.

• Physical Therapy Rehabilitation Science
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• v.4 no.2
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• pp.66-72
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• 2015

Objective: The aim of this study was to investigate the effect of balance training with plantar flexor stretching on ankle dorsi flexion range of motion (ROM), balance, and gait ability in stroke patients. Design: A randomized controlled pilot trial. Methods: Thirty stroke patients volunteered to participate in this study. The subjects were randomly allocated to two groups: the experimental group (n=15) received the neurodevelopment therapy plus balance training with plantar flexor stretching for 20 minutes in one session. The control group (n=15) received the same neurodevelopment therapy plus plantar flexor static stretching for 20 minutes in one session. Both groups underwent sessions four times a week, for a total of 4 weeks. Measurements included passive range of motion (PROM), active range of motion (AROM) of ankle dorsiflexion using a goniometer, timed up and go (TUG), the functional reaching test (FRT), and the 10 m walk test (10 MWT). Results: There were significant improvements in AROM and PROM of ankle dorsiflexion, TUG, and FRT scores after the intervention in the experimental group (p<0.05). However, the control group showed no statistically significant differences except for PROM of ankle dorsiflexion. The experimental group showed a significant improvement in PROM, TUG, and FRT scores compared to the control group (p<0.05). Conclusions: Balance training with plantar flexor stretching improves ankle dorsiflexion ROM and balance ability in patients with stroke. Therefore, this therapeutic intervention will be effective for rehabilitation of stroke patients in the clinical setting.