• Carbon letters
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• v.12 no.2
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• pp.107-111
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• 2011

Polyacrylonitrile (PAN) fibers were pre-oxidized in a temperature range of 180-275$^{\circ}C$. The effects of positive and negative stretching on the structure and morphology of PAN fiber in the pre-oxidation process were studied by FTIR spectroscopy, XRD, and SEM. Mechanical property changes were also investigated. No changes in the movement and intensity of functional groups of PAN fibers were caused by positive stretching of up to 10% and negative stretching down to -8%. The crystal structure can be affected by the positive stretching and negative stretching. The maximum strength is 479.81 MPa when the stretching is positive, and the maximum strength is 420.55 MPa when the stretching is negative.

• Journal of International Academy of Physical Therapy Research
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• v.10 no.1
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• pp.1717-1724
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• 2019

Background : Several studies have suggested different arguments for the effect of stretching exercises and core muscle exercises on flexibility and balance ability. Objective : To determine the effects of stretching exercises and core muscle exercise on flexibility and balance ability. Design : Quasi experimental research Method : The study applied exercise interventions (three sessions per week for 6 weeks) on 40 subjects. The subjects were divided into stretching and core muscle exerciseing groups to identify the change of flexibility and balance ability. Sit- and- reach test results and hip hyperextension were measured for identifying changes in flexibility, and the Romberg test and Pedalo stabilizer were used for changes in balance ability. Results : Both the stretching exercise and core muscle exercise groups showed a statistically significant increase in flexibility (p<.05). However, the stretching exercise group showed a statistically significant increase in balance ability (p<.05), whereas the core muscle exercise group showed partially statistically significant differences in this par t(p>.05). In the analysis of the differences in the amount of change in flexibility, based on the types of exercise, stretching exercises showed a significant difference (p<.05), whereas a significant difference was not found in the amount of change in balance ability (p>.05). Conclusions : These findings indicate that stretching exercises are the more effective intervention for improving and maintaining flexibility, whereas there is no difference between stretching and core muscle exercises with respect to improving balance ability.

• Journal of the Korean Society of Physical Medicine
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• v.18 no.4
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• pp.77-87
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• 2023

PURPOSE: The purpose of this study was to investigate the changes in the flexibility and elasticity of the muscles when the hamstrings were stretched in one direction and when they were stretched in three directions. METHODS: In this study the subjects were divided into two groups, namely the 'one-direction stretching exercise of the hamstring muscle in the neutral position' group (female: 14 people, male: 14 people) and the 'three-way stretching exercise' group (female: 12 people, male: 14 people) considering the positions of the three hamstring muscles. The elasticity and flexibility of the hamstring muscles were measured before and after the self-extension exercise, and the average value of two measurements was noted. To evaluate the flexibility of the hamstring muscle, a 'sit and reach' test was performed, and muscle elasticity was measured using the MyotonPRO® device. RESULTS: After the stretching exercise, flexibility increased in both groups. In terms of muscle elasticity, the body dynamic strength and resonance frequency of the stretching one-direction stretching group decreased after the stretching exercise. CONCLUSION: To alter the muscle characteristics and increase the flexibility when performing a stretching exercise, selecting and stretching only one muscle with the lowest range of motion yields effective results. The ideal technique to be employed appears to be to stretch the entire hamstring muscle in one direction from the neutral position.

• The Journal of Korean Physical Therapy
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• v.35 no.5
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• pp.125-131
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• 2023

Purpose: This study examined the acute effects of static and dynamic stretching on the flexibility of the hamstring, dynamic balance ability, and function of the lower extremities in healthy adults. Methods: Thirty participants were assigned randomly to three groups: static stretching group (SSG), basic dynamic stretching group (BDSG), and 5 sec dynamic stretching group (5DSG). SSG performed three sets of 30 seconds of static stretching. BDSG performed a single-leg deadlift (SLD) at the same time as SSG, and 5DSG performed SLD held for five seconds. Hamstring flexibility, dynamic balance ability, and lower extremity function were evaluated before and after intervention. Results: The hamstring flexibility significantly improved in all groups (p<0.05). The dynamic balance ability improved significantly after intervention in all groups except BDSG in the anterior direction (p<0.05). There were significant differences in the posterolateral and posteromedial direction in all groups. The function of the lower extremity showed significant improvement over time only in BDSG (p<0.05). Conclusion: This study suggested that basic dynamic stretching and 5 sec dynamic stretching positively affect the hamstring flexibility, dynamic balance ability, and lower extremity function. Therefore, it is recommended to include dynamic stretching in a program for improving the hamstring flexibility, dynamic balance ability, and the lower extremity function. In addition, it is recommended to apply it at different times depending on the purpose.

• PNF and Movement
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• v.7 no.4
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• pp.1-7
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• 2009

Purpose : This paper reviews on the method of PNF stretching. Methods : This is literature study with Pubmed, medline, SPORT Discus, EBSCO, ProQuest and books. Results : PNF stretching is effective for increasing range of motion than static and ballistic stretching. CR(contract-relax) technique is effective and CRAC(contract-relax with agonist contraction) technique including agonist contraction is more effective. A minimum of one repetition, twice or three times per week is required for range of motion gains, needs to be conducted continueously. A minimum of 20% contraction intensity and more than 3 seconds contraction duration are needed to increase range of motion. Inclusion of static stretching of antagonist and agonist contraction is more effective. Conclusions : PNF stretching is more effective for increasing range of motion than other stretching methods, but, clinicians need to select proper techniques according to subjects and muscles, and conduct carefully when applying technique.

• PNF and Movement
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• v.19 no.1
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• pp.87-95
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• 2021

Purpose: The purpose of this study was to determine the effects of talus stability taping during gastrocnemius stretching on ankle passive dorsiflexion, talus posterior glide, and balance in subjects with limited ankle dorsiflexion. Methods: Fifteen subjects (eight males and seven females) with limited ankle dorsiflexion participated in this study. Ankle passive dorsiflexion range of motion (ROM), talus posterior glide, and the lower quarter Y-balance test (YBT-LQ) were measured pre-stretching, after applying gastrocnemius stretching (GS), and after applying gastrocnemius stretching with talus stability taping (GSTST). The two types of stretching were performed at random. Results: Ankle passive dorsiflexion ROM was significantly increased by both types of stretching (p < 0.05), and ROM was significantly more increased post-GSTST than post-GS (p < 0.05). In addition, talus posterior glide was significantly increased post-GSTST than pre-stretching and post-GS (p < 0.05). However, there was no significant difference between post-GS and pre-stretching (p > 0.05). YBT-LQ score was significantly increased post-GSTST than pre-stretching (p < 0.05). Conclusion: Gastrocnemius stretching with talus stability taping is an effective method for subjects with limited ankle dorsiflexion to improve ankle passive dorsiflexion, talus posterior gliding, and balance.

• Korean Journal of Occupational Health Nursing
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• v.30 no.3
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• pp.120-131
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• 2021

Purpose: This study aimed to compare the effects of an 8 week, self-managed, app-based and poster-based stretching program on musculoskeletal symptoms, flexibility, stretching frequency, self-efficacy, social support, and musculoskeletal disorder knowledge in small manufacturing business workers. Methods: This was a cluster randomized, two-group pretest-posttest design. Workers were assigned to either an app-based (n=20) or a poster-based (n=25) stretching intervention. Both groups received an educational class. The app group also received mobile phone text messages and an app with stretching videos, stretching alarms, stretching records, and information on musculoskeletal disorders. The poster group received workplace stretching posters. Data were collected from April to September 2018 and analyzed with the 𝑥² test, paired t-test, and independent t-test. Results: There was only a significant difference in social support. Significant increase in flexibility and musculoskeletal symptoms were noted for both groups, but social support and musculoskeletal disorder knowledge were significantly changed only in the poster group. More than half of the workers practiced stretching at least 3 times a week. Conclusion: The 8 week, self-managed, workplace stretching program was effective to increase flexibility and stretching frequency to at least 3 times a week. However, effective interventions for musculoskeletal symptoms could not be identified.

• Physical Therapy Korea
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• v.13 no.2
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• pp.43-51
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• 2006

The term thoracic outlet syndrome (TOS) is used to describe patients with compressed subclavian arteries, veins, and brachial plexuses in the region of the thoracic outlet. The objective of this study was to evaluate a scalenus stretching exercise that aims to restore normal function to patients with TOS. This study consisted of 60 patients with symptoms of TOS, and divided the patients into 3 groups: one that received manual therapy, one that practiced self stretching, and a control group. Each group consisted of 20 patients. This study assessed the efficacy of scalenus stretching exercise by examining the resting pain, tenderness, spherical grip power, and pinch grip power of patients. The data were analyzed using one-way ANOVA, Scheffe post hoc test, and independent t-test. The results showed that resting pain was statistically significant within the manual therapy and self stretching groups (p<.05), and that the resting pain of the manual therapy group was more statistically significant than that of the self stretching group (p<.05). Tenderness, spherical grip power, and pinch grip were statistically significant within the manual therapy and self stretching groups (p<.05), but there was no statistically significant difference between the two groups (p>.05). Finally I could see that there were no statistical differences between manual therapy and self stretching to improve the symptoms of the patients with TOS. These results imply that self stretching by patients is as important as manual therapy by a physical therapist.

• Physical Therapy Korea
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• v.17 no.2
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• pp.67-74
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• 2010

The purpose of this study was to examine the acute effects of nerve mobilization, static stretching, and hold-relax on the flexibility of hamstring muscles and their surface electromyographic (EMG) responses to passive stretches in poststroke hemiparesis. This study was a randomized cross-over trial. Fourteen subjects received three treatment sessions in random order with each consisting of ten repetitions. The treatment sessions included nerve mobilization, static stretching, and hold-relax. The treatment sessions were held at least 24 hours apart to minimize any carryover effect. The outcome was measured by the distance between the greater trochanter and lateral malleolus and hamstring EMG activity during passive knee extension stretching. Repeated-measures analysis of variance showed significant changes in hamstring flexibility and EMG activity in main effect of time pre, post and followup (p<.05). However, no significant differences occurred among the three stretching techniques. No technique was consistently found to be superior. The three stretching techniques in this study make it difficult to determine the most effective technique. Therefore, clinicians use nerve mobilization of effective stretching techniques with other stretching techniques.

• The Journal of Korean Physical Therapy
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• v.22 no.1
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• pp.1-7
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• 2010

Purpose: Stretching exercises are commonly used in conjunction with sports and rehabilitation. Weassessed the immediate effects of stretching on passive stiffness of the hamstring muscles and knee range of motion (ROM) using three stretching techniques. Methods: A total of 45 participants were recruited. Isokinetic equipment was used to measure the passive stiffness of hamstring muscles and an inclinometer was used to measure active and passive ROM of the knee joint pre and post stretching. Stiffness was then calculated based on the incline of the torque-angle relationship. The test conditions for Group I were $3{\times}30$ seconds of static stretches using the hamstring muscle, Group II were $3{\times}30$ seconds of static stretches using the hamstring muscle with ankle dorsiflexion, and Group IIII had $3{\times}30$ seconds of active stretching. Results: Group II had significantly higher excursion of active ROM and Group IIIhad significantly higher excursion of passive muscle stiffness. All of the groups had significantly higher active and passive ROM and significantly lower muscle stiffness after stretching. The participants showed no change in hamstring muscle stiffness on the following day. Conclusion: Stretching has significant acute effects on ROM and muscle stiffness and canbe used in warm-up protocols for reducing muscle stiffness before a variety of exercise programs.