Background: Both the rapid concentric and eccentric contractions during exercise repeatedly impose excessive stress on muscle tissue. The hamstring muscles are very susceptible to injury due to the tensile stress. Various interventions are currently being undertaken to prevent strain injury before exercise. Stretching is the most common method and is known to have a positive effect on flexibility and muscle performance. However, relatively few studies have investigated the potential negative factors of stretching. Objects: The purpose of this study was to examine changes in pain following the different intensity of the stretching and types of physical stress. Methods: The subjects were divided into three groups based on the intensity of stretching: 100% (S100), 75% (S75), and 50% (S50) of the measured force at the point of discomfort in static stretching and 100% (P100), 75% (P75), and 50% (P50) of the maximum voluntary isometric contraction in Proprioceptive Neuromuscular Facilitation (PNF) stretching. The pain individual subjects perceived after stretching was measured via a Visual Analog Scale (VAS) and compared between the groups Results: Despite the decrease in the intensity of static stretching, no decrease in VAS value was observed. In PNF stretching, a significant decrease was observed at P50 compared to P100. S100 was significantly higher than P75 and P50. Conclusion: Previous studies have shown that PNF has a superior or the same effect on flexibility in comparison with static stretching. This effect was maintained even in moderate intensity. PNF stretching performed under moderate rather than high intensive static stretching, which causes pain and discomfort, might be recommended in clinical settings.

Commercial ultra-high-strength PAN-based carbon fibers (T1000G) were heat-treated at the temperature range of 2300– 2600 °C under a constant stretching of 600 cN. After continuous high-temperature graphitization treatment, microstructures, mechanical properties and thermal stability of the carbon fibers were investigated. The results show that the T1000G carbon fibers present the similar round shape with a smooth surface before and after graphitization, indicating the carbon fibers are fabricated by dry–wet spinning. In comparison, the commercial high-strength and high-modulus PAN-based carbon fibers (M40JB and M55JB) present elliptical shapes with ridges and grooves on the surface, indicating the carbon fibers are fabricated by wet spinning. After graphitization treatment from 2300 to 2600 °C under a constant stretching of 600 cN, the Young’s modulus of the T1000G carbon fibers increases from about 436 to 484 GPa, and their tensile strength decreases from about 5.26 to 4.45 GPa. The increase in Young’s modulus of the graphitized T1000G carbon fibers is attributed to the increase in the crystallite sizes and the preferred orientation of graphite crystallites along the fiber longitudinal direction under a constant stretching condition. In comparison with the M40JB and the M55JB carbon fibers, the graphitized T1000G carbon fibers are easier to be oxidized, which can be contributed to the formation of more micropores and defects during the graphitization process, thus leading to the decrease in the tensile strength.

Background: Lumbar lordosis is a result of muscle shortening and may cause low back pain. Objective: To examine the effects of static and dynamic stretching on lumbar lordosis and low back pain in university students. Stretching is an intervention that can be applied to shortened muscles; however, very few studies have compared the effects of static and dynamic stretching on lumbar lordosis and low back pain. Design: Randomized controlled clinical trial (single-blind) Methods: The 12 selected subjects were randomly assigned static stretching and dynamic stretching groups each containing six students. The subjects in each group performed their respective stretching programs for 17 minutes, 3 times a week for 4 weeks. Lumbar lordotic angle, low back pain, and Oswestry Disability Index (ODI) were measured before and after the intervention. Results: Intragroup comparisons showed significant reductions in lumbar lordotic angle and low back pain in the static stretching group while the dynamic stretching group showed significant decreases in lumbar lordotic angle, low back pain, and ODI. The intergroup comparisons showed significantly greater differences between pre- and post-intervention in lumbar lordotic angle and low back pain in the dynamic stretching group compared to those in the static stretching group while ODI did not show any intergroup difference. Conclusions: The results of this study indicated that, while both static and dynamic stretching helped to reduce the lumbar lordotic angle and low back pain, dynamic stretching was more effective in alleviating lumbar lordotic angle and low back pain compared to static stretching.

Background: Limitations in hip flexion caused by tight hamstrings lead to excessive lumbar flexion and low back pain. Accordingly, many studies have examined how to stretch the hamstring muscle. However, no study has focused on the effect of hamstring eccentric exercise for tight hamstrings on trunk forward bending. Objects: We compared the short-term effect of hamstring eccentric exercise (HEE) and hamstring static stretching (HSS) on trunk forward bending in individuals with tight hamstrings. Methods: Thirty individuals with tight hamstrings participated in the study. The subjects were randomly allocated to either a HEE or HSS group. To determine whether the hamstrings were tight, the active knee extension (AKE) test was performed, and the degree of hip flexion was measured. To assess trunk forward bending, subjects performed the fingertip to floor (FTF) and modified modified Schober tests, and the degree of trunk forward bending was measured using an inclinometer. We used paired t-tests to compare the values before and after exercise in each group and independent t-tests to compare the two groups on various measures Results: The FTF test results were improved significantly after the exercise in both groups, and AKE for both legs increased significantly in both groups. There was no significant difference in the hip angles, mmS test results, or degree of trunk forward bending between groups after the exercise. No test results differed significantly between the two groups at baseline or after the exercise. Both groups increased hamstring flexibility and trunk forward bending. Conclusion: HSS and the HEE groups increased hamstring flexibility and trunk forward bending. However, HEE has additional benefits, such as injury prevention and muscle strengthening.

Background: There have been many studies on self-myofascial release (SMR) stretching, but there are few comparative studies on the effects of massages using a release ball, which is a type of the SMR method. Objective: To investigate the immediate effects of release ball massage and self- stretching on proprioceptive sensory, hamstring’s temperature, range of motion (ROM) muscle strength,. Design: Crossover study. Methods: Thirty women in 20’s at S University in Busan voluntarily participated in the study. Participants were random to release ball group (n=15) or selfstretching group (n=15). Both groups performed 3 sets of exercises, stretching for 30 seconds and resting for 15 seconds in each position. The proprioceptive sensory, temperature of the hamstring muscle, ROM, and strength were measured before exercise, 5 minutes after exercise, and 30 minutes after exercise. Results: Release ball group showed significant differences in muscle length and temperature over time (p<.05). The comparison between two group over time showed significant differences in muscle length, temperature, and muscle strength (p<.05). Conclusions: These results demonstrate that release ball massage and selfstretching are beneficial for improving hamstring's temperature, ROM and muscle strength.

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.

Background: A tight iliotibial band (ITB) may lead to lateral patellar maltracking, compression, and tilt, and dominant vatus lateralis (VL) muscle activation relative to vastus medialis oblique (VMO) can laterally displace the patella, which leads to anterior knee pain. Therefore, an effective management technique is needed to stabilize the patella in individuals with tight ITB. Increased stability during the modified Thomas test has the potential to decrease compensatory motion and thus to selectively stretch the ITB. Objects: The purpose of this study was to determine the effects of ITB stretching in the modified Thomas test position on ITB flexibility, patellar translation, and muscle activities of the VMO and VL during quadreceps-setting (QS) exercise in individuals with tight ITB. Methods: Twenty-one subjects with tight ITB were recruited. Digital inclinometer was used to measure the hip adduction angle during the modified Ober test. Universal goniometer was used to measure the hip abduction angle during the modified Thomas test. Ultrasonography was used to measure the patella-condylar distance. Electromyography was performed to collect data of muscle activities. Paired t-test was used to determine the statistical significance between pretest and posttest. Results: The range of hip adduction in modified Ober test increased (p=.04) and the range of hip abduction in the modified Thomas test decreased after ITB stretching (p<.01). There was no difference between lateral patellar translation (p=.18). VMO muscle activity significantly increased after ITB stretching during QS (p<.01). VL muscle activity had no difference after stretching. Conclusion: The ITB stretching in the modified Thomas test position can be suggested as a management method for improving ITB flexibility and VMO muscle activity in individuals with tight ITB.

This study was conducted to examine the effects of Evjenth-Hamberg stretching of the sternocleidomastoid, upper trapezius, and pectoralis major on the lung function of adults with forward neck posture. The subjects were 20 adult students in P university located in Pohang, Korea, whose degree of head forward displacement measured according to NEW YORK state posture test was mild. The subjects were randomly and equally assigned to the Evjenth- Hamberg Stretching group (EHSG, n=10) and the control group (CG, n=10). Their forced vital capacity (FVC), slow vital capacity (SVC), and maximal voluntary ventilation (MVV) were measured before and after the experiment. In within-group comparison, only the EHSG experienced statistically significant improvement in FVC, forced expiratory volume in the first second (FEV1), and peak expiratory flow (PEE) after the experiment, compared to before the experiment (.05<p). In between-group comparison, the PEE of EHSG was statistically significantly higher than CG (.05<p). Regarding SVC, only the EHSG experienced statistically significant improvement in inspiratory vital capacity after the experiment, compared to before the experiment. With regard to MVV, only the EHSG experienced statistically significant improvement in their tidal volume during maximal voluntary ventilation after the experiment compared to before the experiment. Our results indicated that Evjenth- Hamberg stretching was an effective physical therapy intervention to improve the lung function of adults with FHP by correcting their head forward displacement.

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° to 13.09° in the joint mobilization group (p<.05) and from 19.00° to 16.83° 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.

The purpose of this study was to investigate whether static stretching or Thera-band stretching of hamstrings is more effective in improving the flexibility of hamstrings. A total of 40 participants performed stretching 3 times a week for 4 weeks, and a sitting trunk flexion meter was used to measure the flexibility of the hamstrings. Differences in hamstring flexibility before and after the application of static and Thera-band stretching were analyzed, and differences between the stretching methods were also analyzed. As a result, hamstring flexibility increased significantly after the static stretching program (p=.000), and also increased significantly after the Thera-band stretching program (p=.000). Although both programs were effective in improving hamstring flexibility, but there was no significant difference between the two groups (p=.058). Therefore, static stretching and Thera-band stretching are effective interventions to improve and maintain hamstring flexibility.

This study aims to identify the effects of extracorporeal shock wave therapy and stretching technique on flexibility, muscle tone and pressure pain threshold of a shortened hamstring. A total of 40 patients with hamstring shortening was randomly assigned to either the extracorporeal shock wave therapy group (n=20) or extracorporeal shock wave therapy with stretching technique group (n=20) to identify the effects of the two different forms of physical therapy intervention. All the participants underwent extracorporeal shockwave therapy twice a week for 3 weeks, and the extracorporeal shockwave therapy with stretching technique group performed stretching techniques with the same frequency for 3 weeks. To measure hamstring flexibility before and after intervention, the passive straight leg raising test was performed, and muscle tone and pressure pain threshold were assessed. The flexibility of the hamstrings significantly improved, while the pressure pain threshold increased in both groups. These findings suggest that the effective in improving hamstring flexibility, reducing muscle tone, and increasing pressure pain threshold in adults with hamstring shortening.

Background:Limitation of hamstring extensibility is often associated with various musculoskeletal problems such as alterations in posture and walking patterns. Thus, certain appropriate strategies need to be established for its management.Objects:The aim of this study was to compare the effects of the neural mobilization technique and static stretching exercises on popliteal angle and hamstring compliance in young women with short hamstring syndrome (SHS).Methods:Thirty-three women with SHS were randomly assigned to either group-1 (n1=17) that underwent the neural mobilization technique or group-2 (n2=16) that underwent the static stretching exercises. Outcome measures included the active popliteal angle (APA) and a hamstring’s electromyographic (EMG) activity at a maximum popliteal angle of the baseline. Intervention for each group was performed for a total time of 3-min (6 sets of a 30-sec application).Results:There were significant interactions between time and group in the APA [group-1 (pre-test to post-test): 69.70±8.14° to 74.14±8.07° and group-2: 68.66±7.42° to 70.52±7.92°] (F1,31=6.678, p=.015) and the EMG activity of the hamstring (group-1: 1.12±.30μV to .69±.31μV and group-2: 1.19±.49μV to 1.13±.47 μV)(F1,31=6.678, p=.015). Between-group comparison revealed that the EMG activity of the hamstring was significantly different at post-test between the groups (p<.05). Furthermore, in within-group comparison, group-1 appeared to be significantly different for both variables between pre- and post-test (p<.05); however, group-2 showed significant difference in only the APA between pre- and post-test (p<.05).Conclusion:These findings suggest that the neural mobilization technique and static stretching exercises may be advantageous to improve hamstring compliance in young women with SHS, resulting in a more favorable outcome in the neural mobilization technique.

The purpose of this study was to investigate the effects of strengthening and stretching exercises on forward head angle and static·dynamic balance ability. 21 adults with the forward head posture were participated in this study. Subjects were randomly assigned to strengthening exercise group I(n=11) and stretching exercise group II (n=10) respectively. Each group were underwent six intervention over the period of 2 weeks, each session lasting 30 minutes. During a preliminary examination, forward head angle and static∙dynamic balance were measured, and a post examination was conducted that involved same procedure as preliminary examination. There were significant differences in forward head angle after exercise in both groups. In the strengthening group, center of gravity total sway distances was significantly changed under all conditions. In the stretching group, center of gravity total sway distances was significantly changed when subjects had their eyes open while standing on an foam surface. There were significant changes in center of gravity sway velocities in the strengthening group under all conditions, and the same was true in the stretching group only when the subjects had their eyes open while standing on an foam surface. In the comparison between groups, eyes closed while standing on a firm surface was significantly different. There was a significant difference in dynamic balance of the stretching group when the subjects tilted their bodies forward, and there was a statistically significant difference between groups under the same condition. The results of this study suggest that forward head posture can be corrected through therapeutic exercise, and muscle strengthening exercise more effective in improving static balance of forward head posture more than stretching exercise.

The purpose of this study was to identify the effects of continuous muscle strengthening applied to the antagonist of the sternocleidomatoid, upper trapezius, and pectoralis major, which are the shortened muscles of forward head posture(FHP) subjects, and Evjenth-Hamberg stretching(EHS) applied to the shortened muscles on changes in pressure pain threshold(PPT). Twenty subjects were divided into the continuous antagonist strengthening( CAS) group(n=10) and the EHS group(n=10), and each group performed its respective exercise three times a week for a six week period. The results were as follows: The comparison of changes in PPT within each group before and after the treatment showed a statistically significant difference( p<.05) according to the treatment period and a statistically significant difference according to the treatment period and method(p<.05). While the comparison of the tests of between subjects effects between the groups did not show a statistically significant difference, the CAS group exhibited better effects. The above results suggest that the combined application of CAS and EHS generates better effects on changes in PPT than the single application of EHS. Given that stretching and muscle strengthening exercises even for the short research period of six weeks could change the PPT, continuous exercises and a correct postural habit for a longer period of time are likely to help prevent chronic pain and correct FHP

The purpose of this study is to investigate effects of Maitland orthopedic manipulative physiotherapy and stretching on pain, cervical range of motion, and muscle tone of adults with forward neck posture. A total 40 subjects were divided into a Maitland OMPT group(n=20) and a stretching group(n=20), performing joint mobilization exercise and stretching three times per week for six weeks. As for changes in pain, statistically significant decrease were found before and after the exercise within group comparison( p<.01), while no statistically significant difference was observed between-group comparison. In changes in cervical range of motion before and after the exercise, the Maitland OMPT group showed statistically significant increase(p<.01) in flexion, (left lateral flexion(p<.05), extension, left rotation, right rotation, and right lateral flexion, while the stretching group showed statistically significant increase(p<.05) in extension(p<.01), left rotation, left lateral flexion, right rotation, and right lateral flexion. However, no significant differences in between group comparison in flexion, extension, right rotation, left rotation, right lateral flexion and left lateral flexion. The results of measuring muscle tone changes showed that the Maitland OMPT group and the stretching group did not show significance in within and between group comparison(p<.05). In conclusion, the Maitland OMPT and stretching were effective on improving pain and range of motion.

This research was conducted to investigate the effect of continuous antagonistic muscle strengthening exercise and Evjenth-Hamberg stretching on the pulmonary function of university students with abnormal transformation of forward head posture(FHP). The results of study subject to the continuous antagonistic muscle strengthening(CAS) group(n=10) and Evjenth- Hamberg stretching(EHS) group(n=10) that was conducted 3 times a week for 6 weeks are as follow. FVC, IVC, and MVV all were shown to be significant in the pre·post comparison between the CAS group and EHS group(p<.05), and significant difference was shown for MW between the two groups(p<.05) in which the CAS group showed better effect. Based on the results above, it is considered that combining continuous antagonistic muscle strengthening exercise has better effect on pulmonary function compared to application of only Evjenth-Hamberg stretching.

This study examined the effects of stretching and sling stabilizing exercises on changes in the angle of the cervical spine in military neck patients. The subjects were 20 adults diagnosed with a military neck(male:10, female:10) and they were randomly and equally assigned to a stretching exercise group and a sling stabilization exercise group. The total study period was four weeks. The intervention was applied three times per week for 60 minutes per each time. Before conducting the exercise, X-ray of each group was photographed to measure craniospinal angle(CVA) and cranial rotation angle(CRA). According to the result of comparing the two groups in changes in the cervical spine angle, there was no significant difference, and the result of comparing pre- and post-intervention was that there was significant change in CVA and CRA in the stretching group (p<.05) but there was no significant change in CVA and CRA in the sling stabilization exercise. Such result suggests stretching exercise is good for improving a military neck and stretching is more effective than sling in the therapeutic intervention for a military neck.

The purpose of this study is to provide fundamental clinical data for the treatment plan and rehabilitation of patients with cervical hypolordosis by comparing the cervical headache and muscle activity after cervical stretching exercise and cervical traction, which are generally applied to patients with cervical hypolordosis. The research subjects included 20 patients without gender division who were diagnosed with cervical hypolordosis. After applying cervical stretching exercise and cervical traction for six weeks, cervical headache and the activity of the muscles around the cervical vertebra(upper trapezius muscle, sternocleidomastoid muscle, splenius capitis muscle, and anterior temporal muscle) were investigated and the following results were obtained. In a comparison of the within group intervention effects of the two groups, cervical pain statistically significantly decreased in the cervical stretching exercise group. According to the results of analyzing the change of muscle tension in the upper trapezius muscle, both the cervical traction group and showed a statistically significant within group difference in the left and right side. According to the results of analyzing the change in the muscle tension of the splenius capitis muscle, both groups showed a statistically significant within group difference in the left and right side. In a betweengroup comparison, a statistically significant difference in the right side was observed. These results confirm that cervical vertebra traction and cervical stretching exercise decrease the cervical headache and muscle activity of the upper trapezius muscle and the splenius capitis muscle among patients with cervical hypolordosis.

본 연구에서는 중공사막의 기계적 강도와 투과유속을 동시에 높이고자, 열유도 상전이법을 이용하여 중공사막 제조 후 연속적으로 연신공정을 적용하여 고투과성 중공사막을 제조하였다. 또한, 고분자함량별 연신된 중공사막을 제조하여 연신온도, 연신율에 따른 물성 변화를 관찰하였다.

The objective of this study was to determine the duration of maintained calf muscle flexibility gained in young adults with calf muscle tightness, as measured by increases in ankle active and passive dorsiflexion range of motion (DFROM) after three stretching interventions. Twenty subjects (5 men and 15 women) with calf muscle tightness received the following three stretching interventions in one leg (assigned at random): static stretching (SS), eccentric training on stable surface (ETS), and eccentric training on unstable surfaces (ETU). The subjects received all three interventions to the same leg, applied in a random order. Each intervention had a break of at least 24 h in-between, in order to minimize any carryover effect. Each intervention used two types of stretching: with the calf muscle stretched and both knees straight, and with the knee slightly bent in order to maximize the activation of the soleus muscle. All three interventions were performed for 200 seconds. We measured the duration of maintained calf muscle flexibility through active and passive ankle DFROM before intervention, immediately after intervention (time 0), and then 3, 6, 9, 15, and 30 min after intervention. We found a difference in the duration of maintained calf muscle flexibility between the three interventions. In the ETS and ETU interventions, a significant improvement in calf muscle flexibility, both ankle active and passive dorsiflexion ranges of motion (ADFROM and PDFROM), was maintained for 30 min. In the SS intervention, however, ADFROM before 9 min and PDFROM before 6 min were statistically different from the baseline. Our results suggest that ETS and ETU may be more effective than SS for maintaining calfmuscle flexibility in young adults.