Influence of hamstring length on the standing position and flexion range of motion of the pelvic angle, lumbar angle, and thoracic angle

Effect of Eutony, Holistic Gymnastics and Pilates on hamstring flexibility and back pain in pre-adolescent girls: Randomized clinical trial

OBJECTIVE

This study aimed to evaluate the effects of Eutony, Holistic Gymnastics, and Pilates on hamstring flexibility and back pain in pre-adolescent girls.

METHODS

This randomized prospective quantitative clinical trial compared the effects of Eutony, Holistic Gymnastics, and Pilates on hamstring flexibility and back pain. The sample consisted of 80 pre-adolescent girls aged 10-13 years and divided into three groups: Eutony, with 26 girls; Holistic Gymnastics, 27 girls; and Pilates, 27 girls. The participants underwent ten 1-h weekly interventions. Hamstring flexibility was evaluated using fingertip-to-floor, sit-and-reach, and hip angle tests; back pain was evaluated using the Body Posture Evaluation Instrument questionnaire and the way they carried their backpack by the Layout for Assessing Dynamic Posture. Descriptive statistical analysis, analysis of variance, and Kruskal-Wallis test were performed at a 5 % significance level (p < 0.05).

RESULTS

The three body practices increased hamstring flexibility in all fingertip-to-floor (7.77 cm), hip angle (5.58°), and sit-and-reach evaluations (9.07 cm). Before the intervention, 66.25 % of participants complained of back pain. After the intervention, only 37.50 % continued with the complaint. Moreover, 25 % of pre-adolescent girls started to carry their school backpack correctly.

CONCLUSION

Eutony, Holistic Gymnastics, and Pilates increased hamstring flexibility, reduced back pain complaints, and incentivized the girls to carry the school backpack correctly.

REGISTRY OF CLINICAL TRIALS

Brazilian Registry of Clinical Trials ReBEC (RBR-25w6kk).

Effect of PNF stretching performed in the AKE position on hip, knee, and ankle flexibility

BACKGROUND

To measure hamstring flexibility, the active knee extension (AKE) test is preferred over the straight leg raise (SLR) test as it can be used to measure hamstring flexibility more selectively. However, hamstring stretching is primarily conducted in the SLR position (maximal hip flexion in the supine position) as it allows for maximal hip flexion in the supine position.

OBJECTIVE

This study evaluates the effects of proprioceptive neuromuscular facilitation (PNF) stretching in the AKE position (maximal knee extension with 90∘ flexion of the hip in the supine position) on hip, knee, and ankle flexibility.

METHODS

SLR, AKE, and active dorsiflexion (ADF) tests were used to determine the range of motion (ROM) before (pre-ROM) and after (post-ROM) stretching. PNF stretching consisted of maximal isometric knee flexion at the end range with external resistance to prevent knee flexion. One set of PNF stretches (five trials of six seconds each) was conducted.

RESULTS

The post-ROMs of hip, knee, and ankle measured via the SLR, AKE, and ADF tests, respectively, were significantly higher than the pre-ROMs.

CONCLUSIONS

The improvement in knee flexibility was greater than the improvement in hip and ankle flexibility. The AKE position is recommended in clinical settings during PNF stretching for individuals with hamstring tightness. Furthermore, PNF stretching in the AKE position increases the ADF ROM.

Sustainable effectiveness of kinetic chain stretching on active hip flexion movement and muscle activation for hamstring tightness: A preliminary investigation

BACKGROUND

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.

OBJECTIVE

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.

METHODS

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.

RESULTS

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.

CONCLUSION

KCS produced more sustainable effectiveness in hip flexion movement and EMG motor control patterns in participants with HAM tightness than AHS.

A randomised controlled trial between hamstring muscle tightness and lumbar lordotic angle

Shortening of the hamstring muscles is a common problem in both symptomatic and asymptomatic individuals. Low back pain and injury caused by postural deficits might be caused by an imbalance of this muscle. The various degrees of hamstring muscle stiffness and its impact on trunk postures are relatively unknown. The goal of this study was to see how different hamstring muscle length (HML) ranges influenced lumbar lordotic angle (LLA). Sixty asymptomatic healthy male and female subjects with a mean age of 40.4±9.2 years and a body mass index of 25.5± 2.2 kg/m2 participated in this study. Subjects were randomly assigned to one of three groups (n=20) with hamstring muscle lengths of 111-120 degrees, 121-130 degrees, or 131-140 degrees, respectively by using a random number generator. The LLA was estimated on a lateral lumbosacral radiograph using the Kinovea application, and hamstring muscle length was measured using the active knee extension test at the university’s rehabilitation centre within a week of subject selection. The Pearson correlation test was used to examine the relationship between LLA and HML, and one-way ANOVA was used to compare the two groups. The correlation coefficients were expressed using 95% confidence intervals. A significant relationship between LLA and HML was observed in 111-120 degrees and 121-130 degrees groups (P<0.05), whereas, the HML >130 degrees group had no influence on LLA (P>0.05). The findings show that hamstring muscle tightness between 111 and 130 degrees has a negative impact on lumbar curvature mechanisms. As a result, hamstring muscle tightness less than 130 degrees should be addressed first in clinical stretching programs for patients. The findings also suggest that instead of focusing on HML, rehabilitation specialists should devote more time to other high-priority interventions, particularly in patients with hamstring muscle lengths greater than 130 degrees.

Influence of hamstring flexibility on running kinematics in adolescent long-distance runners

BACKGROUND

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.

RESEARCH QUESTION

Does hamstring flexibility influence running kinematics in adolescent long-distance runners?

METHODS

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.

RESULTS

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).

SIGNIFICANCE

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.

Changing the pattern of the back-muscle flexion-relaxation phenomenon through flexibility training in relatively inflexible young men

Although several studies have investigated the back-muscle flexion-relaxation phenomenon (FRP), the effect of individual flexibility on the FRP has been discussed infrequently, with very limited data on the influence of flexibility training on the FRP. This study thus examined the effect of flexibility training on the change of back-muscle FRP pattern in relatively inflexible young men. We collected and analyzed the valid data from 20 male participants (10 each with high and low flexibility included in the control and trained groups, respectively) when flexing their trunks at seven trunk flexion positions (0°-90°, in increments of 15°); their erector spinae and hamstring activation, pelvic tilt, and lumbosacral angle were then recorded. After 7 weeks of flexibility training for the low-flexibility group, no difference in flexibility was discovered between this group and the control (originally high-flexibility) group. The trunk flexion experiment was then repeated. The results showed that before the training stage, the low-flexibility group had lower erector spinae and higher hamstring activation, a larger pelvic tilt, and a smaller lumbosacral angle. By contrast, after training, the erector spinae and hamstring activation, pelvic tilt, and lumbosacral angle were significantly changed, and no intergroup differences were observed in FRP patterns. The study results suggest that flexibility training changes lumbopelvic movement and thereby reduces the degree of the back-muscle FRP when trunk flexion is performed.

Utility of Natural Sitting Lateral Radiograph in the Diagnosis of Segmental Instability for Patients with Degenerative Lumbar Spondylolisthesis

BACKGROUND

Segmental instability in patients with degenerative lumbar spondylolisthesis is an indication for surgical intervention. The most common method to evaluate segmental mobility is lumbar standing flexion-extension radiographs. Meanwhile, other simple radiographs, such as standing upright radiograph, a supine sagittal magnetic resonance imaging (MRI) or supine lateral radiograph, or a slump or natural sitting lateral radiograph, have been reported to diagnose segmental instability. However, those common posture radiographs have not been well characterized in one group of patients. Therefore, we measured slip percentage in a group of patients with degenerative lumbar spondylolisthesis using radiographs of patients in standing upright, natural sitting, standing flexion, and standing extension positions as well as supine MRI.

QUESTIONS/PURPOSES

We asked: (1) Does the natural sitting radiograph have a larger slip percentage than the standing upright or standing flexion radiograph? (2) Does the supine sagittal MRI reveal a lower slip percentage than the standing extension radiograph? (3) Does the combination of the natural sitting radiograph and the supine sagittal MRI have a higher translational range of motion (ROM) and positive detection rate of translational instability than traditional flexion-extension mobility using translational instability criteria of greater than or equal to 8%?

METHODS

We retrospectively performed a study of 62 patients (18 men and 44 women) with symptomatic degenerative lumbar spondylolisthesis at L4 who planned to undergo a surgical intervention at our institution between September 2018 and June 2019. Each patient underwent radiography in the standing upright, standing flexion, standing extension, and natural sitting positions, as well as MRI in the supine position. The slip percentage was measured three times by single observer on these five radiographs using Meyerding's technique (intraclass correlation coefficient 0.88 [95% CI 0.86 to 0.90]). Translational ROM was calculated by absolute values of difference between two radiograph positions. Based on the results of comparison of slip percentage and translational ROM, we developed the diagnostic algorithm to evaluate segmental instability. Also, the positive rate of translational instability using our diagnostic algorithms was compared with traditional flexion-extension radiographs.

RESULTS

The natural sitting radiograph revealed a larger mean slip percentage than the standing upright radiograph (21% ± 7.4% versus 17.7% ± 8.2%; p < 0.001) and the standing flexion radiograph (21% ±7.4% versus 18% ± 8.4%; p = 0.002). The supine sagittal MRI revealed a lower slip percentage than the standing extension radiograph (95% CI 0.49% to 2.8%; p = 0.006). The combination of natural sitting radiograph and the supine sagittal MRI had higher translational ROM than the standing flexion and extension radiographs (10% ± 4.8% versus 5.4% ± 3.7%; p < 0.001). More patients were diagnosed with translational instability using the combination of natural sitting radiograph and supine sagittal MRI than the standing flexion and extension radiographs (61% [38 of 62] versus 19% [12 of 62]; odds ratio 3.9; p < 0.001).

CONCLUSION

Our results indicate that a sitting radiograph reveals high slip percentage, and supine sagittal MRI demonstrated a reduction in anterolisthesis. The combination of natural sitting and supine sagittal MRI was suitable to the traditional flexion-extension modality for assessing translational instability in patients with degenerative lumbar spondylolisthesis.

LEVEL OF EVIDENCE

Level III, diagnostic study.

The Beighton Score as a measure of generalised joint hypermobility

The Beighton Score (BS) is a set of manoeuvres in a nine-point scoring system, used as the standard method of assessment for Generalised Joint Hypermobility (GJH). It was originally developed as an epidemiological tool used in screening large populations for GJH, but later adopted as a clinical tool for diagnostic purposes. Its ability to truly reflect GJH remains controversial, as joints within the scoring system are predominantly of the upper limb and disregard many of the major joints, preventing a direct identification of GJH. Furthermore, a consistent finding in the literature whereby the BS failed to identify hypermobility in joints outside the scoring system suggests its use as an indirect indicator of GJH is also not viable. As such, the collective findings of this review demonstrate a need for a change in clinical thinking. The BS should not be used as the principle tool to differentiate between localised and generalised hypermobility, nor used alone to exclude the presence of GJH. Greater emphasis should be placed on a clinician’s judgement to identify or exclude GJH, according to its full definition.

Instrument assisted soft tissue mobilization (IASTM) versus stretching: A comparison in effectiveness on hip active range of motion, muscle torque and power in people with hamstring tightness

BACKGROUND

Instrument-assisted soft tissue mobilization (IASTM) is a new technique that has been known to be effective in reducing muscle tightness in athletics. However, little is known about its effect on the range of motion, muscle power, and torque compared to manual stretching among non-athletics. Thus, the study was aimed to compare the effectiveness between IASTM and manual stretching in improving hip flexion active range of motion (ROM), muscle torque and power on hamstring muscle complex (HMC) tightness in one session.

METHOD

Twenty-three young male college students with unilateral hamstring tightness measured via straight leg raising (SLR) test (<65°) were randomly assigned to one of two groups. Twelve participants received the application of IASTM (group 1), and eleven received manual stretching (group 2). Hip flexion active ROM was measured via goniometer, the torque & power of the hamstring muscle were measured using Humac isokinetic dynamometer, before and after both interventions. (ISRCTN17693345).

RESULTS

There was no significant difference in the improvement of hip flexion active ROM (69.6 ± 6.6 vs 72.5 ± 7.9, p = .34), HMC torque (63.7 ± 14.5 vs 53.2 ± 16.3, p = .14), and HMC power (47.8 ± 11.8 vs 40.9 ± 16.3, p = .34) between group 1 and group 2 respectively. When a comparison was made within each group, significant improvements in hip active flexion ROM was found in both groups (p's < .001), and HMC power was significantly improved in group 1 (p = .04) but not in group 2.

CONCLUSION

The current study findings demonstrate that IASTM was as effective as manual stretching in improving hip flexion active ROM, muscle torque and power among non-athletic people with HMC tightness.

Lower Limb Movement Pattern Differences Between Males and Females in Squatting and Kneeling

Movement pattern differences may contribute to differential injury or disease prevalence between individuals. The purpose of this study was to identify lower limb movement patterns in high knee flexion, a risk factor for knee osteoarthritis, and to investigate kinematic differences between males and females, as females typically develop knee osteoarthritis more commonly and severely than males. Lower extremity kinematic data were recorded from 110 participants completing 4 variations of squatting and kneeling. Principal component analysis was used to identify principal movements associated with the largest variability in the sample. Across the tasks, similar principal movements emerged at maximal flexion and during transitions. At maximal flexion, females achieved greater knee flexion, facilitated by a wider base of support, which may alter posterior and lateral tibiofemoral stress. Principal movements also detected differences in movement temporality between males and females. When these temporal differences occur due to alterations in movement velocity and/or acceleration, they may elicit changes in muscle activation and knee joint stress. Movement variability identified in the current study provides a framework for potential modifiable factors in high knee flexion, such as foot position, and suggests that kinematic differences between the sexes may contribute to differences in knee osteoarthritis progression.

Effectiveness of hamstring stretching using a pressure biofeedback unit for 4 weeks: A randomized controlled trial

Background

Stretching and length test of hamstring muscles have been performed commonly to manage lower back pain (LBP) in sports rehabilitation. Previous literatures addressed that stretching techniques and length test of hamstring muscles should be performed with the pelvic maintained in an anterior tilt position. However, there is no study to determine the effectiveness of pressure biofeedback unit (PBU) to maintain in anterior pelvic tilting (APT) on length test and stretching of hamstring muscles.

Objective

To determine the effectiveness of hamstring muscles stretching using a PBU.

Methods

Forty participants with shortness of hamstrings randomized into two groups. Participants performed the active knee extension (AKE) stretching without (control group) or with PBU (intervention group) for four weeks. AKE tests without and with PBU were administered three times before and after hamstrings stretching by each group.

Results

The AKE test without PBU showed a significant main effect of time ( p < 0 . 01 ) but not of group ( p = 0 . 55 ) on the AKE angle. The AKE test with PBU showed a significant increase in the AKE angle in the post-intervention compared to the pre-intervention assessments in both groups ( p < 0 . 01 ). The difference of AKE angle between the pre- and post-intervention results was significantly greater in the intervention group than in the control group ( p < 0 . 01 ).

Conclusion

We recommend the use of a PBU to maintain the pelvic anterior tilting position when performing the AKE test or AKE stretching.

Generalized joint hypermobility among school-aged children in Majmaah region, Saudi Arabia

Generalized joint hypermobility (GJH) is common among schoolchildren and usually benign. However, it may progressively lead to joint pain and developmental delay. Identifying GJH in school-aged children would facilitate the monitoring of early changes and planning for early rehabilitative intervention. Epidemiological studies addressing the prevalence of GJH among children in the Gulf region and Arab ethnicity are lacking. Hence, we aimed to determine the prevalence, pattern, and factors associated with GJH among school-aged children in the Majmaah region, Saudi Arabia. Male and female school-aged children 8–14 years of age from the Majmaah region of Saudi Arabia participated in this cross-sectional study. Beighton score was used to assess GJH. Personal characteristics such as age, height, weight, body mass index, and handedness were also collected. Descriptive statistics were obtained for personal characteristics, the point prevalence of hypermobility, frequency of Beighton score distribution, and prevalence of GJH. The associations between specific factors and the presence of GJH were analyzed using chi-square and Mann-whitney tests. Using the Beighton score cutoff ≥ 4 and ≥ 6, 15.2% and 7.6% of the school children in our study were diagnosed with GJH respectively. The prevalence of GJH was higher among females (16.8%) than among males (13.4%), but the difference was not statistically significant. The elbow joints (17.2%) were the most common hypermobile joints and the trunk (0.7%) was the least involved. The children with GJH were younger and had lesser BMI compared to children without GJH (P < 0.05). The prevalence reported in this study among school-aged children was comparable with those reported worldwide.

Trunk muscular endurance, lumbar spine mobility and hip flexibility in sailors with and without low back pain

Abstract Introduction: Low back pain is one of the most common injuries in sailors. Findings in the literature indicate that poor trunk endurance, flexibility and muscle strength are common in individuals with low back pain (LBP). Objective: Analyze trunk muscle endurance, lumbar spine mobility and hip flexibility in windsurfers with and without low back pain. Method: Sailors of both sexes with at least three years’ experience in the sport answered the Nordic Musculoskeletal Questionnaire and were submitted to Schober’s test, the passive straight leg raise (PSLR), the modified Thomas test, and isometric endurance assessment of the flexor, extensor and lateral flexor muscles of the torso. The sailors were divided into two groups (with and without LBP) and compared using the Student’s t-test or Mann Whitney U test. Results: Participants were 22 national-level sailors, 11 with low back pain (LBP) and 11 without (NLBP). The LBP group obtained longer holding times for the trunk extensors (p=0.028) and a greater difference in endurance between the right and left sides for lateral trunk muscles (p=0.030). Both groups obtained results below normative values in most of the tests performed. Conclusion: Sailors with low back pain exhibited greater trunk extensor endurance and a larger imbalance between lateral trunk muscles when compared to those with no LBP. Spinal mobility and hip flexibility were similar between groups.

Acute effects of centrally- and unilaterally-applied posterior-anterior mobilizations of the lumbar spine on lumbar range of motion, hamstring extensibility and muscle activation

BACKGROUND

Lumbar mobilizations are used to clinically treat the lumbar and hamstring region. However, evidence is limited regarding the effectiveness of specific mobilization methods.

OBJECTIVE

To compare central and unilateral posterior-anterior mobilizations (CPA, UPA) of the lumbar spine on lumbar and hamstring range of motion (ROM), and muscle activity (sEMG).

METHODS

Twenty participants received CPA, UPA, or no mobilization (CON) on separate occasions (crossover design). Post-treatment outcome measures were ROM during active lumbar flexion (ALF) and active knee extension (AKE), as well as sEMG of the Erector Spinae (ES) and Biceps Femoris (BF) during these movements.

RESULTS

sEMG was possibly to very likely lower following CPA (mean difference range =-5% to -21%) and UPA (-7% to -36%), while ROM was most likely greater (-12% to 25% and -17% to 24%, respectively). Most sEMG measures were possibly to likely lower following UPA versus CPA (-18% to -11%), while AKE ROM was possibly greater (-5.5%). Differences in ES sEMG (-2.5%) and ROM (-1.4%) during ALF were unclear and most likely trivial, respectively.

CONCLUSIONS

CPA and UPA mobilizations increase lumbar and hamstring ROM whilst reducing local muscle activity. These effects appear to be greater for UPA mobilizations when compared with CPA.

Predicting the influence of hip and lumbar flexibility on lifting motions using optimal control

Computational models of the human body coupled with optimization can be used to predict the influence of variables that cannot be experimentally manipulated. Here, we present a study that predicts the motion of the human body while lifting a box, as a function of flexibility of the hip and lumbar joints in the sagittal plane. We modeled the human body in the sagittal plane with joints actuated by pairs of agonist-antagonist muscle torque generators, and a passive hamstring muscle. The characteristics of a stiff, average and flexible person were represented by co-varying the lumbar range-of-motion, lumbar passive extensor-torque and the hamstring passive muscle-force. We used optimal control to solve for motions that simulated lifting a 10 kg box from a 0.3 m height. The solution minimized the total sum of the normalized squared active and passive muscle torques and the normalized passive hamstring muscle forces, over the duration of the motion. The predicted motion of the average lifter agreed well with experimental data in the literature. The change in model flexibility affected the predicted joint angles, with the stiffer models flexing more at the hip and knee, and less at the lumbar joint, to complete the lift. Stiffer models produced similar passive lumbar torque and higher hamstring muscle force components than the more flexible models. The variation between the motion characteristics of the models suggest that flexibility may play an important role in determining lifting technique.

Hamstring and Ankle Flexibility Deficits Are Weak Risk Factors for Hamstring Injury in Professional Soccer Players: A Prospective Cohort Study of 438 Players Including 78 Injuries

BACKGROUND

Hamstring injuries remain a significant injury burden in sports such as soccer that involve high-speed running. It has repeatedly been identified as the most common noncontact injury in elite male soccer, representing 12% of all injuries. As the incidence of hamstring injuries remains high, investigations are aimed at better understanding how to prevent hamstring injuries. Stretching to improve flexibility is commonly used in elite-level sports, but risk factor studies have reported contradicting results, leading to unclear conclusions regarding flexibility as a risk factor for hamstring injuries.

PURPOSE

To investigate the association of lower limb flexibility with the risk of hamstring injuries in professional soccer players.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

All teams (n = 18) eligible to compete in the premier soccer league in Qatar (Qatar Stars League [QSL]) underwent a comprehensive musculoskeletal assessment during their annual periodic health evaluation at Aspetar Orthopaedic and Sports Medicine Hospital in Doha, Qatar. Variables included passive knee extension and ankle dorsiflexion range of motion. A clustered multivariate Cox regression analysis was used to identify associations with the risk of hamstring injuries. Receiver operating characteristic (ROC) curves were calculated to determine sensitivity and specificity.

RESULTS

A total of 438 unique players (72.4% of all QSL players) competed for 601 player-seasons (148 players competed both seasons) and sustained 78 hamstring injuries. Passive knee extension range of motion (hazard ratio [HR], 0.97 [95% CI, 0.95-0.99]; P = .008) and ankle dorsiflexion range of motion (HR, 0.93 [95% CI, 0.88-0.99]; P = .02) were independently associated with the injury risk. The absolute differences between the injured and uninjured players were 1.8° and 1.4 cm, respectively, with small effect sizes ( d < 0.2). The ROC curve analyses showed an area under the curve of 0.52 for passive knee extension and 0.61 for ankle dorsiflexion, indicating failed to poor combined sensitivity and specificity of the 2 strength variables identified in the multivariate Cox regression analysis.

CONCLUSION

This study identified deficits in passive hamstring and ankle dorsiflexion range of motion as weak risk factors for a hamstring injury. These findings have little clinical value in predicting the risk of future hamstring injuries, and test results must therefore be interpreted cautiously in athletic screening.

Relationship between mechanical factors and pelvic tilt in adults with and without low back pain

BACKGROUND

The assessment of the lumbo-pelvic complex parameters is the basic procedure during the examination of the patients with low back pain syndrome (LBP).

OBJECTIVE

The aim of the study was to define the relationship between pelvic tilt and following factors: age, BMI, ability to activate deep abdominal muscles, iliopsoas and hamstrings muscles length, lumbar lordosis and thoracic kyphosis angle value, in adults with and without low back pain.

METHODS

The study covered a group of 60 female students aged 20-26. Average age was 22 years ± 1.83 (median = 22.5 years). In order to investigate the relationship between the anterior pelvic tilt and the analysed variables, simple linear regression and multiple linear regression were carried out.

RESULTS

Individuals with and without pain differed significantly in terms of age, p < 0.001. There was a statistically significant relationship between the anterior pelvic tilt and the LBP (R2 = 0.07, p = 0.049) and the lumbar lordosis (R2 = 0.13, p = 0.02).

CONCLUSIONS

The position of the pelvis depends on age, angle value of lumbar lordosis and BMI. Individuals with and without pain differed significantly in terms of the anterior pelvic tilt. The risk of LBP incidence increased with age in the study group.

Non-structural misalignments of body posture in the sagittal plane

BACKGROUND

The physiological sagittal spinal curvature represents a typical feature of good body posture in the sagittal plane. The cervical and the lumbar spine are curved anteriorly (lordosis), while the thoracic segment is curved posteriorly (kyphosis). The pelvis is inclined anteriorly, and the lower limbs' joints remain in a neutral position. However, there are many deviations from the optimal body alignment.The aim of this paper is to present the most common types of non-structural misalignments of the body posture in the sagittal plane.

MAIN BODY OF THE ABSTRACT

The most common types of non-structural misalignments of body posture in the sagittal plane are as follows: (1) lordotic, (2) kyphotic, (3) flat-back, and (4) sway-back postures. Each one may influence both the skeletal and the muscular system leading to the functional disturbance and an increased strain of the supporting structures. Usually, the disturbances localized within the muscles are analyzed in respect to their shortening or lengthening. However, according to suggestions presented in the literature, when the muscles responsible for maintaining good body posture (the so-called stabilizers) are not being stimulated to resist against gravity for an extended period of time, e.g., during prolonged sitting, their stabilizing function is disturbed by the hypoactivity reaction resulting in muscular weakness. The deficit of the locomotor system stability triggers a compensatory mechanism-the stabilizing function is overtaken by the so-called mobilizing muscles. However, as a side effect, such compensation leads to the increased activity of mobilizers (hyperactivity) and decreased flexibility, which may finally lead to the pathological chain of reaction within the musculoskeletal system.

CONCLUSIONS

There exist four principal types of non-structural body posture misalignments in the sagittal plane: lordotic posture, kyphotic posture, flat-back posture, and sway-back posture. Each of them can disturb the physiological loading of the musculoskeletal system in a specific way, which may lead to a functional disorder.When planning postural corrective exercises, not only the analysis of muscles in respect to their shortening and lengthening but also their hypoactivity and hyperactivity should be considered.

Slump sitting X-ray of the lumbar spine is superior to the conventional flexion view in assessing lumbar spine instability

BACKGROUND CONTEXT

Flexion radiographs have been used to identify cases of spinal instability. However, current methods are not standardized and are not sufficiently sensitive or specific to identify instability.

PURPOSE

This study aimed to introduce a new slump sitting method for performing lumbar spine flexion radiographs and comparison of the angular range of motions (ROMs) and displacements between the conventional method and this new method.

STUDY DESIGN

This study used is a prospective study on radiological evaluation of the lumbar spine flexion ROMs and displacements using dynamic radiographs.

PATIENT SAMPLE

Sixty patients were recruited from a single spine tertiary center.

OUTCOME MEASURE

Angular and displacement measurements of lumbar spine flexion were carried out.

METHOD

Participants were randomly allocated into two groups: those who did the new method first, followed by the conventional method versus those who did the conventional method first, followed by the new method. A comparison of the angular and displacement measurements of lumbar spine flexion between the conventional method and the new method was performed and tested for superiority and non-inferiority.

RESULTS

The measurements of global lumbar angular ROM were, on average, 17.3° larger (p<.0001) using the new slump sitting method compared with the conventional method. They were most significant at the levels of L3-L4, L4-L5, and L5-S1 (p<.0001, p<.0001 and p=.001, respectively). There was no significant difference between both methods when measuring lumbar displacements (p=.814).

CONCLUSION

The new method of slump sitting dynamic radiograph was shown to be superior to the conventional method in measuring the angular ROM and non-inferior to the conventional method in the measurement of displacement.

In vivo relationship between pelvis motion and deep fascia displacement of the medial gastrocnemius: anatomical and functional implications

Different authors have modelled myofascial tissue connectivity over a distance using cadaveric models, but in vivo models are scarce. The aim of this study was to evaluate the relationship between pelvic motion and deep fascia displacement in the medial gastrocnemius (MG). Deep fascia displacement of the MG was evaluated through automatic tracking with an ultrasound. Angular variation of the pelvis was determined by 2D kinematic analysis. The average maximum fascia displacement and pelvic motion were 1.501 ± 0.78 mm and 6.55 ± 2.47 °, respectively. The result of a simple linear regression between fascia displacement and pelvic motion for three task executions by 17 individuals was r = 0.791 (P < 0.001). Moreover, hamstring flexibility was related to a lower anterior tilt of the pelvis (r = 0.544, P < 0.024) and a lower deep fascia displacement of the MG (r = 0.449, P < 0.042). These results support the concept of myofascial tissue connectivity over a distance in an in vivo model, reinforce the functional concept of force transmission through synergistic muscle groups, and grant new perspectives for the role of fasciae in restricting movement in remote zones.

Lumbar Extension during Stoop Lifting is Delayed by the Load and Hamstring Tightness

[Purpose] This study investigated the relationship between lumbar pelvic rhythm and the physical characteristics of stoop lifting. [Subjects and Methods] Participants performed a stoop lifting task under two conditions: with and without load. We assessed the lumbar kyphosis and sacral inclination angles using the SpinalMouse^® system, as well as hamstring flexibility. During stoop lifting, surface electromyograms and the lumbar and sacral motions were recorded using a multi-channel telemetry system and flexible electrogoniometers. [Results] In the initial phase of lifting, lumbar extension was delayed by load; the delay showed a negative correlation with sacral inclination angle at trunk flexion, whereas a positive correlation was observed with electromyogram activity of the lumbar multifidus. Additionally, a positive correlation was observed between sacral inclination angle and hip flexion range of motion during the straight leg raise test. [Conclusion] We found that a disorder of the lumbar pelvic rhythm can be caused by both load and hamstring tightness. In the initial phase of stoop lifting, delayed lumbar extension is likely to lead to an increase in spinal instability and stress on the posterior ligamentous system. This mechanism shows that stoop lifting of a load may be harmful to the lower back of people with hamstring tightness.

Effects of Inclined Treadmill Walking on Pelvic Anterior Tilt Angle, Hamstring Muscle Length, and Trunk Muscle Endurance of Seated Workers with Flat-back Syndrome

[Purpose] This study investigated the effects of inclined treadmill walking on pelvic anterior tilt angle, hamstring muscle length, and back muscle endurance of seated workers with flat-back syndrome. [Subjects] Eight seated workers with flat-back syndrome who complained of low-back pain in the L3–5 region participated in this study. [Methods] The subjects performed a walking exercise on a 30° inclined treadmill. We measured the pelvic anterior tilt angle, hamstring muscle length, and back muscle endurance before and after inclined treadmill walking. [Results] Anterior pelvic tilt angle and active knee extension angle significantly increased after inclined treadmill walking. Trunk extensor and flexor muscle endurance times were also significantly increased compared to the baseline. [Conclusion] Inclined treadmill walking may be an effective approach for the prevention or treatment of low-back pain in flat-back syndrome.

The Relationship Between Hamstring Muscle Extensibility and Spinal Postures Varies with the Degree of Knee Extension

The aim was to determine the relationship between hamstring muscle extensibility and sagittal spinal curvatures and pelvic tilt in cyclists while adopting several postures. A total of 75 male cyclists were recruited for this study (34.79 ± 9.46 years). Thoracic and lumbar spine and pelvic tilt were randomly measured using a Spinal Mouse. Hamstring muscle extensibility was determined in both legs by a passive knee extension test. Low relationships were found between hamstring muscle extensibility and spinal parameters (thoracic and lumbar curvature, and pelvic tilt) in standing, slumped sitting, and on the bicycle (r= .19;P> .05). Significant but low relationships were found in maximal trunk flexion with knees flexed (r= .29;P< .05). In addition, in the sit-and-reach test, low and statistically significant relationships were found between hamstring muscle extensibility for thoracic spine (r= –.23;P= .01) and (r= .37;P= .001) for pelvic tilt. In conclusion, hamstring muscle extensibility has a significant relationship in maximal trunk flexion postures with knees flexed and extended, but there are no relationships while standing or on the bicycle postures.

The comparison of the effects of three physiotherapy techniques on hamstring flexibility in children: a prospective, randomized, single-blind study

The aim of the study was to evaluate changes in hamstring flexibility in 120 asymptomatic children who participated in a 6-week program consisting of one physiotherapy session per week and daily home exercises. The recruitment criteria included age (10-13 years), no pain, injury or musculoskeletal disorder throughout the previous year, physical activity limited to school sport. Subjects were randomly assigned to one of the three groups: (1) post-isometric relaxation - PIR (n = 40), (2) static stretch combined with stabilizing exercises - SS (n = 40) and (3) stabilizing exercises - SE (n = 40). Hamstring flexibility was assessed with straight leg raise (SLR), popliteal angle (PA) and finger-to-floor (FTF) tests. The examinations were conducted by blinded observers twice, prior to the program and a week after the last session with the physiotherapist. Twenty-six children who did not participate in all six exercise sessions with physiotherapists were excluded from the analysis. The results obtained by 94 children were analyzed (PIR, n = 32; SS, n = 31; SE, n = 31). In the PIR and SS groups, a significant (P<0.01) increase in SLR, PA, FTF results was observed. In the SE group, a significant (P<0.001) increase was observed in the SLR but not in the PA and FTF (P>0.05). SLR result in the PIR and SS groups was significantly (P<0.001) higher than in the SE group. As far as PA results are concerned, a significant difference was observed only between the SS and SE groups (P = 0.014). There were no significant (P = 0.15) differences regarding FTF results between the three groups. Post-isometric muscle relaxation and static stretch with stabilizing exercises led to a similar increase in hamstring flexibility and trunk forward bend in healthy 10-13-year-old children. The exercises limited to straightening gluteus maximus improved the SLR result, but did not change the PA and FTF results.

Differences between two subgroups of low back pain patients in lumbopelvic rotation and symmetry in the erector spinae and hamstring muscles during trunk flexion when standing

The present study was performed to examine lumbopelvic rotation and to identify asymmetry of the erector spinae and hamstring muscles in people with and without low back pain (LBP). The control group included 16 healthy subjects, the lumbar-flexion-rotation syndrome LBP group included 17 subjects, and the lumbar-extension-rotation syndrome LBP group included 14 subjects. Kinematic parameters were recorded using a 3D motion-capture system, and electromyography parameters were measured using a Noraxon TeleMyo 2400T. The two LBP subgroups showed significantly more lumbopelvic rotation during trunk flexion in standing than did the control group. The muscle activity and flexion-relaxation ratio asymmetries of the erector spinae muscles in the lumbar-flexion-rotation syndrome LBP group were significantly greater than those in the control group, and the muscle activity and flexion-relaxation ratio asymmetry of the hamstring muscles in the lumbar-extension-rotation syndrome LBP group were significantly greater than those in the control group. Imbalance or asymmetry of passive tissue could lead to asymmetry of muscular activation. Muscle imbalance can cause asymmetrical alignment or movements such as unexpected rotation. The results showed a greater increase in lumbopelvic rotation during trunk flexion in standing among the lumbar-flexion-rotation syndrome and lumbar-extension-rotation syndrome LBP groups compared with the control group. The differences between the two LBP subgroups may be a result of imbalance and asymmetry in erector spinae and hamstring muscle properties.

Effects of pilates training on lumbo-pelvic stability and flexibility

Purpose

This study was performed to assess and compare the effects of Pilates exercise on flexibility and lumbo-pelvic movement control between the Pilates training and control groups.

Methods

A randomized single-blinded controlled design was utilized in the study. Forty healthy male and female volunteers (mean age 31.65±6.21 years) were randomly divided into Pilates-based training (20 subjects) and the control groups (20 subjects). The Pilates group attended 45-minute training sessions, 2 times per week, for a period of 8 weeks. Flexibility and lumbo-pelvic stability tests were determined as outcome measures using a standard “sit and reach test” and “pressure biofeedback” respectively at 0, 4 and 8 weeks of the study.

Results

The results showed that the Pilates training group improved flexibility significantly (P<0.001) during time intervals. This effect was also significantly greater than the control group for both 4 weeks and 8 weeks of the training period (P<0.001). There were 65% and 85% of the subjects from Pilates group passing the lumbo-pelvic stability test at 4 and 8 weeks of training periods respectively. No subjects from the control group passed the test at any stages.

Conclusions

Pilates can be used as an adjunctive exercise program to improve flexibility, enhance control-mobility of trunk and pelvic segments. It may also prevent and attenuate the predisposition to axial musculoskeletal injury.

Acute effects of hamstring stretching on sagittal spinal curvatures and pelvic tilt

The aim of this study was to determine acute effects of hamstring stretching in thoracic and lumbar spinal curvatures and pelvic tilt. Fifty-five adults (29.24 ± 7.41 years) were recruited for this study. Subjects performed a hamstring stretching protocol consisting of four exercises. The session consisted of 3 sets of each exercise and subjects held the position for 20 seconds with a 30-second rest period between sets and exercises. Thoracic and lumbar spinal angles and pelvic tilt were measured with a SpinalMouse in relaxed standing, sit-and-reach test and Macrae & Wright position. Hamstring extensibility was determined by active straight leg raise test and sit-and-reach score. All measures were performed before and immediately after the hamstring stretching protocol. Active straight leg raise angle and sitand-reach score significantly improved immediately after the stretching protocol (p<0.001). Greater anterior pelvic tilt (p<0.001) and lumbar flexion (p<0.05) and a smaller thoracic kyphosis in the sit-and-reach (p<0.001) were found after the stretching protocol. However, stretching produced no significant change on spinal curvatures or pelvic tilt in standing and maximal trunk flexion with knees flexed. In conclusion, static stretching of the hamstring is associated to an immediate change in the sagittal spinal curvatures and pelvic position when performing trunk flexion with knees extended, so that allowing for greater lumbar flexion and anterior pelvic tilt and lower thoracic kyphosis. Hamstring stretching is recommended prior to sport activities involving trunk flexion with the knees straight.

Differences in end-range lumbar flexion during slumped sitting and forward bending between low back pain subgroups and genders

Patterns of lumbar posture and motion are associated with low back pain (LBP). Research suggests LBP subgroups demonstrate different patterns during common tasks. This study assessed differences in end-range lumbar flexion during two tasks between two LBP subgroups classified according to the Movement System Impairment model. Additionally, the impact of gender differences on subgroup differences was assessed. Kinematic data were collected. Subjects in the Rotation (Rot) and Rotation with Extension (RotExt) LBP subgroups were asked to sit slumped and bend forward from standing. Lumbar end-range flexion was calculated. Subjects reported symptom behaviour during each test. Compared to the RotExt subgroup, the Rot subgroup demonstrated greater end-range lumbar flexion during slumped sitting and a trend towards greater end-range lumbar flexion with forward bending. Compared to females, males demonstrated greater end-range lumbar flexion during slumped sitting and forward bending. A greater proportion of people in the Rot subgroup reported symptoms with each test compared to the RotExt subgroup. Males and females were equally likely to report symptoms with each test. Gender differences were not responsible for LBP subgroup differences. Subgrouping people with LBP provides insight into differences in lumbar motion within the LBP population. Results suggesting potential consistent differences across flexion-related tasks support the presence of stereotypical movement patterns that are related to LBP.

The influence of backrest inclination on buttock pressure

Objective

To assess the effects of backrest inclination of a wheelchair on buttock pressures in spinal cord injured (SCI) patients and normal subjects.

Method

The participants were 22 healthy subjects and 22 SCI patients. Buttock pressures of the participants were measured by a Tekscan® pressure sensing mat and software while they were sitting in a reclining wheelchair. Buttock pressures were recorded for 90°, 100°, 110°, 120° and 130° seat-to-back angles at the ischial tuberosity (IT) and sacrococcygeal (SC) areas. Recordings were made at each angle over four seconds at a sampling rate of 10 Hz.

Results

The side-to-side buttock pressure differences in the IT area for the SCI patients was significantly greater than for the normal subjects. There was no significant difference between the SCI patients and the normal subjects in the buttock pressure change pattern of the IT area. Significant increases in pressure on the SC area were found as backrest inclination angle was changed to 90°, 100° and 110° in the normal subjects, but no significant differences were found in the SCI patients.

Conclusion

Most of the SCI patients have freeform posture in wheelchairs, and this leads to an uneven distribution of buttock pressure. In the SCI patients, the peak pressure in the IT area reduced as the backrest angle was increased, but peak pressure at the SC area remained relatively unchanged. To reduce buttock pressure and prevent pressure ulcers and enhance ulcer healing, it can be helpful for tetraplegic patients, to have wheelchair seat-to-back angles above 120°.

Accuracy and feasibility of video analysis for assessing hamstring flexibility and validity of the sit-and-reach test

The accuracy of video analysis of the passive straight-leg raise test (PSLR) and the validity of the sit-and-reach test (SR) were tested in 60 men and women. Computer software measured static hip-joint flexion accurately. High within-session reliability of the PSLR was demonstrated (R > .97). Test-retest (separate days) reliability for SR was high in men (R = .97) and women R = .98) moderate for PSLR in men (R = .79) and women (R = .89). SR validity (PSLR as criterion) was higher in women (Day 1, r = .69; Day 2, r = .81) than men (Day 1, r = .64; Day 2, r = .66). In conclusion, video analysis is accurate and feasible for assessing static joint angles, PSLR and SR tests are very reliable methods for assessing flexibility, and the SR validity for hamstring flexibility was found to be moderate in women and low in men.

Epidemiology of generalized joint laxity (hypermobility) in fourteen-year-old children from the UK: a population-based evaluation

Objective

Although diagnostic criteria for generalized ligamentous laxity (hypermobility) in children are widely used, their validity may be limited, due to the lack of robust descriptive epidemiologic data on this condition. The present study was undertaken to describe the point prevalence and pattern of hypermobility in 14-year-old children from a population-based cohort.

Methods

We performed a cross-sectional analysis using the Avon Longitudinal Study of Parents and Children, a large population-based birth cohort. Hypermobility among children in the cohort (mean age 13.8 years) was measured using the Beighton scoring system. Objective measures of physical activity were ascertained by accelerometry. Data on other variables, including puberty and socioeconomic status, were collected. Simple prevalence rates were calculated. Chi-square tests and logistic regression analyses were used to assess associations of specific variables with hypermobility.

Results

Among the 6,022 children evaluated, the prevalence of hypermobility (defined as a Beighton score of ≥4 [i.e., ≥4 joints affected]) in girls and boys age 13.8 years was 27.5% and 10.6%, respectively. Forty-five percent of girls and 29% of boys had hypermobile fingers. There was a suggestion of a positive association between hypermobility in girls and variables including physical activity, body mass index, and maternal education. No associations were seen in boys.

Conclusion

We have shown that the prevalence of hypermobility in UK children is high, possibly suggesting that the Beighton score cutoff of ≥4 is too low or that this scoring is not appropriate for use in subjects whose musculoskeletal system is still developing. These results provide a platform to evaluate the relationships between the Beighton criteria and key clinical features (including pain), thereby testing the clinical validity of this scoring system in the pediatric population.

Influence of hamstring muscles extensibility on spinal curvatures and pelvic tilt in highly trained cyclists

The purpose of this study was to determine the influence of hamstring muscles extensibility in standing, maximal trunk flexion with knees extended and on the bicycle in lower handlebar-hands position of highly trained cyclists. Ninety-six cyclists were recruited for the study (mean ± SD, age: 30.36 ± 5.98 years). Sagittal spinal curvatures and pelvic tilt were measured in the standing position, maximal trunk flexion with knees extended (sit-and-reach test) and while sitting on a bicycle in lower handlebar-hand position using a Spinal Mouse system. Hamstring muscles extensibility was determined in both legs by passive straight leg raise test (PSLR). The sample was divided into three groups according to PSLR angle: (1) reduced extensibility (PSLR < 80º; n = 30), (2) moderate hamstring extensibility group (PSLR = 80º - 90º; n = 35), and (3) high hamstring extensibility (PSLR = > 90º; n = 31). ANOVA analysis showed significant differences among groups for thoracic (p < 0.001) and pelvic tilt (p < 0.001) angles in the sit-and-reach test. No differences were found between groups for standing and on the bicycle position. Post hoc analysis showed significant differences in all pairwise comparisons for thoracic angle (p < 0.01) and pelvic angle (p < 0.001) in the sit-and-reach test. No differences were found in lumbar angle in any posture. In conclusion, the hamstring muscles extensibility influence the thoracic and pelvic postures when maximal trunk flexion with knees extended is performed, but not when cyclists are seated on their bicycles.

Sagittal spinal and pelvic postures of highly-trained young canoeists

The objective of this study was to determine the sagittal spinal curvatures and pelvic position in standing and kneeling in the canoe in young canoeists. Forty-four young highly-trained canoeists (mean age: 15.11 ± 0.61 years) were recruited. Thoracic and lumbar curvatures and pelvic inclination were evaluated with a Spinal Mouse system in standing position and in the base position (kneeling on one knee in the canoe) and catch phase of the stroke. The mean thoracic kyphosis, lumbar lordosis and pelvic inclination in standing were 44.66 ± 8.80º, −30.34 ± 8.31º, and 14.20 ± 7.32º, respectively. In the canoe, the thoracic, lumbar and pelvic angles were 39.66 ± 9.52º, −24.32 ± 6.79º, and 15.18 ± 4.34º, respectively, for the base position (p<0.001 with respect to standing, except for pelvic inclination), and 28.93 ± 10.45º, −13.45 ± 10.60º, and 37.61 ± 6.27º, respectively, for the catch phase of the stroke (p<0.001 with respect to standing and base position). A higher percentage of hyperkyphotic postures in standing than in the canoe was found, while thoracic hypokyphosis increased in the catch phase of the stroke. In regards to the lumbar curve, the percentage of hypolordosis postures in the base position was higher than when standing. Lumbar kyphotic postures were detected in the catch phase of the stroke. In conclusion, the standing thoracic hyperkyphosis in young canoeists may be related to factors other than the posture and movement in the canoe. The canoeists adopted a lumbar flexed posture at the catch phase of the stroke, although this position may not affect the sagittal configuration of lumbar spine in standing. Postural training should be included in the training program of canoeists to improve the thoracic posture in the standing position.

Effect of stretch positions on hamstring muscle length, lumbar flexion range of motion, and lumbar curvature in healthy adults

Hamstring stretching is a common practice in physical therapy to change not only hamstring muscle length (HML), but also lumbar flexion range of motion (LROM) or lumbar curvature (LC). Yet limited published research compares the effectiveness of two commonly used hamstring stretch positions, sitting and standing. The purposes of this study were to determine the effect of (1) stretch position on HML; and 2) HML on LROM and LC. Thirty-six participants (M=44.8 years, SD=17.1) with short HML (i.e., with shortness for men ≥45° and for women ≥ 24° of active knee flexion with 90° hip flexion) were measured for HML, LROM, and LC; randomly allocated to one of three groups: (1) hamstring stretching in sitting (SI); (2) standing (ST); or (3) no stretching (control); and remeasured after 4 weeks. Participants in the stretching groups performed two 30-second static stretches 4 days per week for 4 weeks. Multivariate analysis of covariance (MANCOVA) showed significance between the stretching groups and nonstretching group for HML only. Nonsignificance was shown for HML between the stretch positions (i.e., SI-active knee extension (AKE) and ST-AKE), indicating that both were equally effective for increasing HML. However, there was no change in LROM or in LC even though HML increased.