• Journal of the Korean Society of Physical Medicine
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• v.15 no.4
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• pp.1-9
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• 2020

PURPOSE: The current generation has shortened hamstrings due to a sedentary lifestyle, resulting in reduced flexibility of the hamstring and dysfunction. This study was undertaken to compare effects of three different release exercises on hamstring flexibility, in participants with short hamstrings. METHODS: Totally, 20 subjects having short hamstrings were involved in this study. The inclusion criterion for study participation was active knee extension test (AKET) less than 60°. All participants were subjected to 3 methods: hamstring foam roller release (HFRR), sitting self myofascial release (sitting SMR), and standing self myofascial release (Standing SMR). All participants randomly performed all three methods to avoid bias caused by learning or fatigue. Passive knee extension test (PKET), AKET, finger to floor distance test (FTFT), and pelvic tilting angle test (PTAT) were measured pre- and post-exercises. RESULTS: The PKET, AKET and FTFT were significantly increased after HFRR, sitting SMR, and standing SMR exercise (p < .05). However, PTAT was not significantly increased after the three exercises (p > .05). Furthermore, no significant differences were observed between PKET, AKET, FTFT and PTAT subsequent to HFRR, sitting SMR, and standing SMR (p > .05). CONCLUSION: Our results indicate that HFRR, sitting SMR and standing SMR were immediately effective in improving hamstring flexibility in participants with short hamstrings.

• Physical Therapy Korea
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• v.24 no.4
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• pp.1-10
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• 2017

Background: Flexion-relaxation phenomenon (FRP) was a term which refers to a sudden onset of myoelectric silence in the erector spinae muscles of the back during standing full forward flexion. Hamstring muscle length may be related to specific pelvic and trunk movements. Many studies have been done on the FRP of the erector spinae muscles. However, no studies have yet investigated the influence of hamstring muscle flexibility on the FRP of the hamstring muscle and lumbopelvic kinematics during forward bending. Objects: The purpose of this study was to examine the flexion-relaxation ratio (FRR) of the hamstring muscles and lumbopelvic kinematics and compare them during forward bending in subjects with different hamstring muscle flexibility. Methods: The subjects of two different groups were recruited using the active knee extension test. Group 1-consisted of 13 subjects who had a popliteal angle under $30^{\circ}$; Group 2-consisted of 13 subjects who had a popliteal angel above $50^{\circ}$. The kinematic parameters during the trunk bending task were recorded using a motion analysis system and the FRRs of the hamstring muscles were calculated. Differences between the groups were identified with an independent t-test. Results: The subjects with greater hamstring length had significantly less lumbar spine flexion movement and more pelvic flexion movement. The subjects with greater pelvic flexion movement had a higher rate of flexion relaxation during full trunk bending (p<.05). Conclusion: The results of this study suggest that differences in hamstring muscle flexibility might cause changes in people's hamstring muscle activity and lumbopelvic kinematics.

• PNF and Movement
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• v.21 no.1
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• pp.63-74
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• 2023

Purpose: This study aims to compare hamstring flexibility and pressure pain threshold (PPT) after an intervention with proprioceptive neuromuscular facilitation contract-relax (PNF CR) technique, myofascial release (MFR), and a massage gun (MG), as well as to verify the effectiveness of the MG. Methods: This study recruited 36 participants (22 males and 14 females) with shortening of less than 70 degrees upon a straight leg raise (SLR) test, and they were randomly assigned to one of the PNF, MG, and MFR groups, each of which underwent its own protocol for 30 minutes. Flexibility of the hamstring was measured after the intervention using the active and passive knee extension (AKE and PKE) test, the sit and reach test, and PPT. Results: The AKE and PKE angles significantly decreased, as well as significantly increased in flexibility when each of the PNF, MFR, and MG interventions was performed (p<0.05). In addition, there was no significant difference among groups. However, according to the Cohen's D effect size, the MG demonstrated the largest effect size in AKE (d = 1.41) and PNF demonstrated the largest effect size in PKE (d = 1.66) and flexibility (d = 0.63). Conclusion: All interventions used in our study are effective in increasing hamstring flexibility. Based on the Cohen's D effect size, an MG is beneficial to increase the AKE, whereas PNF CR technique is recommended for increasing PKE and flexibility.

• Journal of The Korean Society of Integrative Medicine
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• v.10 no.2
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• pp.115-123
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• 2022

Purpose : The hamstring is a group of three muscles, biceps femoris, semitendinosus, and semimembranosus, placed behind the thigh. The hamstring is one of the most commonly injured muscles and usually occurs during high-speed, high-intensity exercise. The purpose of this study was to investigate the effect of static stretching and eccentric exercise of hamstrings on flexibility, strength, and functional performance. Methods : This study was conducted on 28 healthy adults. Subjects were divided into a static stretching group (n=15) and an eccentric exercise group (n=13). Subjects measured hamstring flexibility (active knee extension test), hamstring strength (concentric and eccentric peak torque), and functional performance (triple hop for distance and modified 20 m sprint). The intervention was conducted three times a week for six weeks. To compare the difference between values before and after the intervention, paired t-test was used, and an independent t-test was used to compare between groups. Results : In both groups, the active knee extension test, concentric peak torque, triple hop test, and 20 m sprint significantly increased after the intervention compared to before the intervention (p<.05). However, no significant difference was found in eccentric peak torque after intervention in both groups (p>.05). No significant difference was found between the two groups in the effect on the variables (p>.05). Conclusion : Both interventions were found to be effective for flexibility, concentric strength, and functional performance. Eccentric exercise and static stretching are recommended to improve the flexibility and functional performance of the hamstring. This study's results will be considered essential data on the effectiveness of static stretching and eccentric exercise.

• Physical Therapy Korea
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• v.22 no.4
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• pp.8-16
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• 2015

The purpose of this study was to evaluate the effects of mobilization of the sciatic nerve on hamstring flexibility, lower limb strength, and gait performance in patients with chronic stroke. This study was a randomized clinical trial with a crossover design. Sixteen subjects were recruited for this study. The subjects were randomly divided into two intervention groups and underwent either of the following two interventions: sciatic nerve mobilization or static stretching of the hamstring. We assessed hamstring flexibility, lower limb strength, and gait performance using a digital inclinometer, a hand-held dynamometer, and the 10-meter walk test, respectively. Subjects had a 24-hour rest period between each session in order to minimize carryover effects. Measurements for each test were assessed prior to and immediately after the intervention sessions. Using a two-way analysis of variance test with repeated measures, data from the two trials were analyzed by comparing the differences between both techniques. The level of statistical significance was set at .05. Sciatic nerve mobilization resulted in significantly better knee extensor strength (p=.023, from $15.32{\pm}5.98$ to $18.16{\pm}6.95kg$) and knee flexor strength (p=.011, from $7.80{\pm}4.80$ to $8.15{\pm}4.24kg$) in the experimental group than in the control group. However, no significant effects of static stretching of the hamstring were observed on hamstring flexibility from the ankle plantar flexion (p=.966) and ankle neutral positions (p=.210) and on gait performance (p=.396). This study indicated that the sciatic nerve mobilization technique may be more effective in muscle activation of the knee extensor muscle and knee flexor muscle than hamstring static stretching technique in patients with chronic stroke.

• PNF and Movement
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• v.13 no.3
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• pp.135-143
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• 2015

Purpose: The purpose of this study was to assess the effect of the proprioceptive neuromuscular facilitation (PNF) relaxation technique (hold relax; HR, contract relax; CR) and static stretch (SS) on hamstring flexibility and vertical jump performance in healthy adults over a four-week period. Methods: Twenty-four healthy adults volunteered to participate in PNF and static stretch sessions. The subjects were divided into three groups as follows: 8 subjects in the SS group, 8 subjects in the HR group, and 8 subjects in the CR group. In the HR and CR groups, contractions lasted 15 seconds per trial and consisted of 5 sets of 15 seconds of hamstring contraction immediately followed by 15 seconds of passive static hamstring stretching. For the static group, the participants were asked to stretch by hanging a leg over a table for 30 seconds. Subjects in all groups performed the exercises three days per week for 4 weeks. The active straight leg raising (ASLR) test, active knee extension (AKE) test, and vertical jump test were performed before the intervention and after 1, 2, and 4 weeks. Results: The SS, HR, and CR techniques effected positive improvement in hamstring flexibility and vertical jump performances but neither of the stretching methods had any statistically significant different effects according to group, although there were interactions (between group and time) in the ALSR group from 1 week to 2 week and in the AKE test from pretest to 1 week. Conclusion: Based on the results of the current study, SS, HR, and CR were shown to affect hamstring flexibility and vertical jump performance in healthy adults. In particular, it was determined that within a short period, hamstring flexibility could be attributed more to CR than to SS.

• Journal of Korean Physical Therapy Science
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• v.30 no.1
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• pp.31-40
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• 2023

Hamstring flexibility is an important factor that affects muscle performance of the lower extremities and is closely associated with sports injuries. Therefore, evaluation of flexibility is important in clinical practice. Results of evaluation are determined by types of tests and cut-off values used; therefore, accurate and detailed understanding of these is necessary before examination. Although the straight leg raise and sit and reach tests are used to evaluate hamstring extensibility, structures including the nerves, fascia, and other muscles can significantly confound the results of these tests. The knee extension test is performed at 90° of hip flexion to minimize the posterior pelvic tilt that occurs during the straight leg test. The knee extension test is most recommended for selective evaluation of hamstring flexibility. The knee extension test is classified into active and passive tests. The cut-off value is usually set at 20° for the active and at 10° for the passive knee extension test. Although a strong association is observed between the two tests, the active knee extension test is preferred in clinical practice because it can be performed by a single examiner, which serves as an advantage. Age, sex, and warm-up exercise tend to affect flexibility; therefore, results should be interpreted with caution. Detailed understanding of each flexibility test is important for reliable evaluation.

• Physical Therapy Rehabilitation Science
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• v.6 no.1
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• pp.45-51
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• 2017

Objective: This study aimed to identify the area with greatest effect using self-myofascial release technique (self-MFR) in the hamstring, suboccipital, and plantar regions. Design: Cross-sectional study. Methods: Twenty-two adult subjects were evaluated for flexibility and hamstring pain threshold after self-MFR. Based on the superficial back line, the self-MFR application areas were the suboccipital region, hamstring, and plantar regions. Self-MFR was applied to each area using a wooden pole for a total of 4 minutes. Self-MFR was applied for 3 days at the same time of day, which was randomly assigned for each subject. Treatment was applied to one area each day. The sit and reach test (SRT), active range of motion (AROM), and passive ROM (PROM) were used to determine changes in flexibility, and an algometer was used to determine pain threshold. Pre/post-self-MFR effectiveness was tested using a paired t-test. Repeated measurement was used to compare self-MFR effects in the suboccipital, hamstring, and plantar regions. Results: When the self-MFR technique was applied to the 3 areas, the SRT showed significant improvement over baseline (p<0.05). Bilateral AROM and PROM showed significant improvements (p<0.05). When the self-MFR technique was applied to the hamstring, the semimembranosus showed a significant change in pain threshold (p<0.05). Conclusions: Our findings suggest that indirect application based on the Anatomy Trains could be effective for those who need to improve muscle flexibility. Moreover, self-MFR easily alleviates myofascial pain while maintaining flexibility, and can be performed at any time and place.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.21 no.1
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• pp.5-11
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• 2015

Background: The purpose of this study was to investigate the effects of Mulligan's straight leg raise with traction technique and hold-relax technique on flexibility of hamstring in people with shortened hamstring. Methods: Thirty two subjects participated in this study. The subjects were assigned to either the Mulligan's straight leg raise with traction technique group (n=16) or the hold-relax technique group (n=16). 90-90 straight leg raise test was performed for evaluation of hamstring shortening at initial time of study. After intervention, immediate effect (immediately after intervention) and lasted effect (60 min after intervention) were assessed. Results: In the both Mulligan's straight leg raise with traction technique and hold-relax technique groups, significant improvements on flexibility of hamstring was observed in immediately and 60 minute after intervention (p<.05). However, there are no significant difference was observed between groups (p>.05). Conclusion: In the results of this study, both Mulligan's straight leg raise with traction technique and hold-relax technique show immediately and 60 minute after evaluation effectiveness in flexibility of hamstring of people with shortened hamstring. In addition, although the difference is not statistically significant, Mulligan's straight leg raise with traction technique was more increased average extension angle of knee joint at 90-90 straight leg raise test than the hold-relax technique.

• 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.