UNASSIGNED: Conventional hamstring (HAM) stretching therapeutic effects are not substantiable in neuromusculoskeletal conditions with HAM tightness or shortness. We developed a kinetic chain stabilization exercise to provide a more sustainable effectiveness in adults with HAM tightness. However, its therapeutic effects and underlying motor mechanisms remain unknown.
UNASSIGNED: To compare the effects of traditional active HAM stretching (AHS) and kinetic chain stretching (KCS) on electromyographic (EMG) amplitude and hip flexion range of motion (ROM) in participants with HAM tightness.
UNASSIGNED: In this randomized controlled trial, 18 participants (mean age: 25.01 ± 2.47 years) with HAM tightness were assigned to the AHS or KCS group. Hip joint movement, EMG amplitude, and onset times were recorded in the bilateral erector spinae, HAM, transverse abdominis/internal oblique (IO), external oblique (EO), and rectus abdominis during a straight leg raise test.
UNASSIGNED: Compared to AHS, KCS led to greater increase in the hip flexion ROM and EMG activation amplitudes in the left and right EO and left IO. Post-test hip flexion ROM data in both the groups were higher than the pre-test data.
UNASSIGNED: KCS produced more sustainable effectiveness in hip flexion movement and EMG motor control patterns in participants with HAM tightness than AHS.

UNASSIGNED: Unilateral osteoarthritis (OA) affects single knees and presents a unique scenario where individuals experience varying degrees of symptoms between their affected and unaffected knees.
UNASSIGNED: This study aims to investigate differences in muscle tightness between symptomatic and asymptomatic knees in individuals with unilateral knee OA while exploring the interplay among pain, functionality, and muscle tightness.
UNASSIGNED: In this cross-sectional study, thirty knee OA patients underwent assessments for hamstring (Active Knee Extension, Straight Leg Raise), iliotibial band (Ober Test), and quadriceps tightness (Modified Thomas Test). Pain intensity was measured using the Visual Analog Scale (VAS), and functional limitations were evaluated via the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).
UNASSIGNED: A negative correlation was observed between participants\' pain and AKE (p= 0.004, r=-0.515), ASLR (p= 0.27, r=-0.403), Ober (p= 0.010, r=-0.461) values. However, no significant correlation was found with the Modified Thomas value (p= 0.204, r=-0.239). There was also a negative correlation between participants\' WOMAC scores and AKE (p= 0.019, r=-0.427), OBER (p= 0.004, r=-0.510), and Modified Thomas (p= 0.022, r=-0.416) values, while ASLR (p= 0.286, r=-0.202) values showed no significant correlation. Comparisons between AKE, Ober, and Modified Thomas values showed higher values in asymptomatic extremities (AKE: p= 0.025, Ober: p= 0.021, Modified Thomas: p= 0.030).
UNASSIGNED: This study emphasizes the significance of muscle tightness in the symptomatic extremities of individuals with unilateral knee OA. The results indicate that increased muscle tightness makes pain worse and limits movement. It\'s crucial for healthcare providers treating OA to focus on improving muscle flexibility, reducing pain, and enhancing overall function.

UNASSIGNED: Although the effect of active warm-up (WU) on acute flexibility enhancement is well documented, the test-induced WU effect in muscle length test has not been widely studied.
UNASSIGNED: This study aimed to verify the test-induced WU effect on hamstring flexibility tests.
UNASSIGNED: The active knee extension (AKE) was performed using the right leg, whereas the straight leg raise (SLR) was performed using the left leg. Ten trials of AKE or SLR were performed: two as the pre-intervention trials (Pre); six as the WU intervention; and another two trials as the post-intervention (Post). During WU, subjects in the WO-Hold group performed six trials of the AKE or SLR without hold, and those in the W-Hold group performed six trials of the AKE or SLR with a 5 s hold.
UNASSIGNED: A significant difference was noted between Pre-AKE and Post-AKE, and between Pre-SLR and Post-SLR, respectively, in both the groups. The effect of WU is clear when performing consecutive AKE or SLR without any additional hold.
UNASSIGNED: Practitioners should be cautious in interpreting the testing result to avoid overestimation of the treatment effect since the test itself may induce substantial WU effect to the target tissues.

UNASSIGNED: Low back pain is a common health issue, and such pains are often associated with muscle tightness. Understanding the link between lower back pain and tight lower extremity muscles is essential for effective pain management and enhanced quality of life.
UNASSIGNED: The objective of this study was to investigate the relationship between lower extremity muscle tightness and pain and disability in individuals with non-specific low back pain (NSLBP).
UNASSIGNED: A total of 52 individuals with NSLBP were enrolled in this cross-sectional study. Lower extremity muscle tightness was assessed using various clinical tests, including the Active Knee Extension Test, Active Straight Leg Raise, Ober Test, and Modified Thomas Test. Pain intensity and disability were evaluated using the Visual Analog Scale and the Oswestry Disability Index, respectively. Statistical analyses were conducted to assess the correlation between muscle tightness, pain, and disability.
UNASSIGNED: The study found weak to moderate negative correlations between lower extremity muscle tightness and both pain intensity and disability in individuals with NSLBP (r: -0.287 to -0.526, p <  0.05). Dominant and non-dominant extremities exhibited differences in muscle flexibility, with the dominant extremity showing greater flexibility (p <  0.05).
UNASSIGNED: In individuals with NSLBP, lower extremity muscle tightness is closely related to pain severity and disability. These findings suggest that lower extremity muscle tightness plays a significant role in the severity of low back pain and disabilities. Additionally, the observed flexibility difference between dominant and non-dominant extremities warrants further investigation for more personalized treatment approaches.

OBJECTIVE: To identify factors associated with shoulder pain in swimmers based on elastic muscle modulus, joint range of motion, and isometric muscle strength.
METHODS: Cohort study.
METHODS: Forty-eight competitive swimmers without shoulder pain (age: 18-28 years; men: 29) were followed-up for 6 months. Baseline measurements of the elastic modulus of the pectoralis minor, supraspinatus, infraspinatus, posterior deltoid, and pectoralis minor muscles were obtained using shear wave elastography. Range of motion and isometric strength were measured using a goniometer and a hand-held dynamometer, respectively. A questionnaire was administered weekly for 6 months to determine shoulder pain occurrence. Each item was compared between shoulders with and without pain at baseline. For participants with shoulder pain exceeding 2 weeks, shear wave elastography and range of motion at baseline (pre pain) and during follow-up (post pain) were compared.
RESULTS: Of 46 swimmers followed-up for 6 months, 20 reported shoulder pain. 14 swimmers with pain were evaluated twice. Participants with shoulder pain during follow-up had significantly higher posterior deltoid and pectoralis minor stiffness at baseline and high lower extremity isometric muscle strength contralateral to the shoulder with pain compared to those without pain (p < 0.05). Swimmers with pain exceeding 2 weeks exhibited no differences in ultrasound shear wave elastography and range of motion at baseline and after pain onset.
CONCLUSIONS: Posterior deltoid and pectoralis minor muscle stiffness, and high isometric lower extremity strength contralateral to the shoulder with pain may be associated with shoulder pain development, thereby indicating the importance of maintaining posterior deltoid and pectoralis minor muscle flexibility during conditioning.

Background  The hamstring muscle is related to the lumbar spine, pelvic, and lower limb movement dysfunction, as well as low back pain and abnormal gait. The kinematic chain\'s distal elements dysfunctions may affect the body\'s proximal segments. There is a biomechanical connection between the foot and proximal segments of the body and its effect on the body\'s functional status, but there is a lack of research that focuses on the correlation between foot posture and hamstring muscle tightness. The study aimed to find the correlation between hamstring muscle tightness and foot posture using the foot posture index (FPI). Methods After obtaining ethical committee approval, necessary authorization was obtained from relevant authorities to proceed with participant screening. Informed consent was obtained from every participant, accompanied by a comprehensive explanation of the study. Screening of participants was conducted based on specific inclusion and exclusion criteria. These criteria were crucial for selecting a homogeneous sample and ensuring the study\'s objectives were met. The assessment of foot posture was carried out using FPI, and hamstring tightness was examined using an active knee extension test. Result and discussion In our study, which included 188 participants aged between 18 and 25 (mean age: 21.91±1.97), we examined the correlation between FPI and active knee extension (AKE) test results. Using Pearson\'s correlation coefficient, we found a statistically significant correlation between the FPI and AKE test results. For the right side, the r-value was 0.678 (p-value = 0.0001); for the left side, the r-value was 0.653 (p-value = 0.0001); and for the total, the r-value was 0.663 (p-value = 0.0001). These findings indicate a significant relationship between the FPI and AKE test results. Conclusion The findings of our study revealed a significant relationship between hamstring tightness and pronation of the foot, as measured by the FPI. Understanding this relationship is crucial as it sheds light on the potential impact of hamstring tightness on foot biomechanics. By establishing this link, our study contributes to the body of knowledge surrounding the prevention of alterations in foot biomechanics. It highlights the importance of addressing hamstring tightness to mitigate potential foot pronation issues. Moreover, the study serves as a stepping stone for future research endeavors. It lays the groundwork for further large-scale investigations that encompass a broader range of age groups.

UNASSIGNED: Patellofemoral pain syndrome (PFPS) is characterized by peripatellar or retro patellar pain, as a result of changes in the physical and biochemical components of the patellofemoral joint. The main contributory factor is being the excessive load on the patellofemoral joint. The change in the flexibility of lower limb muscles is one of the factors for developing PFPS.
UNASSIGNED: To find the association of quadratus lumborum (QL) and lower limb muscles tightness in patients with unilateral PFPS.
UNASSIGNED: 50 PFPS participants (21 male and 29 female) were included and assessed for muscle tightness on both affected and unaffected side. The QL, rectus femoris, hamstring, iliotibial band (ITB) and gastrocnemius tightness were measured using inch tape and mobile inclinometer. A Chi Square test and phi crammer\'s v criteria were used to check the association and the strength of it.
UNASSIGNED: A significant association was found between tightness of rectus femoris (PFPS-right Chi 19.99 p < 0.001; Phi-0.632, PFPS-left Chi-5.52 p = 0.019 and Phi- 0.332), gastrocnemius (PFPS-right Chi 8.78 p = 0.003; Phi-0.419, PFPS-left Chi- 11.41 p = 0.001; Phi- 0.478), iliotibial band (PFPS-right Chi 7.83 p = 0.005; Phi-0.396, PFPS left Chi-3.68 p = 0.055; Phi- 0.27). There was no significant association of hamstring tightness (PFPS-right Chi - 3.68 p = 0.055; Phi-0.055, PFPS left Chi-1.11 p = 0.291; Phi- 0.019) and QL (PFPS right Chi - 1.10 p = 0.293; Phi-0.293, PFPS left Chi-0.79 p = 0.372; Phi- 0.372).
UNASSIGNED: PFPS was associated with tightness of rectus femoris, gastrocnemius, ITB and no association found between hamstring and QL muscle tightness and PFPS.

UNASSIGNED: Kinesio tape has been proposed to improve the muscle extensibility. However, there are contradictory results in the literature.
UNASSIGNED: To investigate the effect of Kinesio tape on hamstring muscle lengthening and on hamstring and quadriceps muscle strengthening in university students with hamstring muscle tightness.
UNASSIGNED: In this pre-post experimental study, 96 female students with hamstring muscle tightness were recruited from Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia, and randomly assigned to Kinesio tape, sham tape, or control groups (32 in each group). The inhibition technique was used for the Kinesio tape application, with the tape being applied from the muscle insertion to the origin. Measurements were taken before and 15 min after the intervention. Outcome measurements included active knee extension test to measure the hamstring muscle length, and isometric strength measurements of hamstring and quadriceps muscles using a handheld dynamometer.
UNASSIGNED: A significant increase in the immediate hamstring muscle length was found in both the Kinesio (P = 0.001) and sham (P = 0.004) tape groups, while no difference was noted in the control group (P = 0.066). The muscle lengthening was significantly greater in the Kinesio tape group than the sham tape (P = 0.001) and control (P = 0.001) groups. There was no difference in the pre- and post-measurements in the quadriceps and hamstring muscle strengths in all three groups.
UNASSIGNED: These results demonstrate that applying Kinesio tape has an immediate effect on hamstring muscle extensibility, but has no effect on the quadriceps and hamstring muscle strengths.
UNASSIGNED: NCT03076840.

Shoulder pain (SP) caused by hitting the shuttlecock is common in young badminton players. The objectives of the present study were to predict the risk factors for SP in young badminton players, and to determine the optimal risk factor cut-off that best discriminates those players who are at higher risk of suffering from SP.
A prospective cohort study was conducted with 45 under-17 badminton players who participated in the Spanish Championship. Data were collected on anthropometric age, sports history, sagittal spinal curves, range of motion (ROM) and maximum isometric strength of shoulder. After 12 months, players completed a SP history questionnaire. Bayesian Student\'s t-analysis, binary logistic regression analysis and ROC analysis were performed.
Overall, 18 (47.4%) players reported at least one episode of SP. The shoulder internal rotation (SIR) ROM showed the strongest association (OR = 1.122; p = 0.035) with SP. The SIR ROM has an excellent ability to discriminate players at increased risk for SP (p = 0.001). The optimal cut-off for SIR ROM, which predicts players with an 81% probability of developing SP, was set at 55° (sensitivity = 75.0%, specificity = 83.3%).
The young badminton players who had a shoulder internal rotation ROM of 55° or less have a higher risk of SP one year later.

Studies have found no or minimal differences in running kinematics between flexible and inflexible adult runners. The interaction between hamstring flexibility and running kinematics has not been reported in adolescent long-distance runners.
Does hamstring flexibility influence running kinematics in adolescent long-distance runners?
Adolescent long-distance runners (n = 140, ages 9-19) were enrolled in our cross-sectional study. Hamstring flexibility was assessed with the forward bending Beighton task. Runners were categorized if they tested positive or negative on the forward bending task. Participants ran at a comfortable self-selected speed on a treadmill. Runners who tested positive on the forward bending task (n = 17) were matched with runners who tested negative on the task (n = 17) according to sex, physical maturation, and running speed. Statistical parametric mapping compared trunk, pelvis, hip, and knee kinematic waveforms throughout the gait cycle and independent sample t tests compared temporal-spatial parameters between the groups.
Runners who tested positive on the forward bending task demonstrated significantly greater anterior pelvic tilt during stance (average difference = 4.8° ± 0.4°, p < .001) and swing (average difference = 4.3° ± 0.2°, p < .01) compared to runners who tested negative on the forward bending task. No significant differences were found between groups for the remaining kinematic waveforms or for any temporal-spatial parameters (p > .05).
This is the first study to report the interaction between hamstring flexibility and running kinematics in adolescent long-distance runners. The greater anterior pelvic tilt demonstrated by runners with greater hamstring flexibility may place more eccentric demands on the hamstring musculature. However, as there were no other differences in joint kinematics or temporal-spatial parameters between groups, greater hamstring flexibility does not appear to have a significant interaction with running kinematics when running at sub-maximal speeds. Our results suggest hamstring flexibility does not predispose adolescent long-distance runners to sub-optimal segment positions associated with running-related injuries.