Comparison of longitudinal sciatic nerve movement with different mobilization exercises: an in vivo study utilizing ultrasound imaging

Comparing the immediate effects of different neural mobilization exercises on hamstring flexibility in recreational soccer players

Background

Hamstring strain injuries remain a challenge for both athletes and clinicians given the high incidence rate, slow healing, and persistent symptoms. Increased tension in the neural structures is a known causative factor for hamstring tightness for which neural mobilization has emerged as a significant adjunct to routine stretching techniques.

Objective

To compare the short-term effects of neural sliding and neural tensioning on hamstring length in male recreational soccer players with hamstring tightness.

Methods

Sixty-two participants between ages 18 and 30 years were randomly assigned to one of the two groups viz. neural sliding or neural tensioning. Participants in either group performed the given stretching protocol in three sets. The Active Knee Extension Test (AKET) and Sit and Reach Test (SRT) were recorded before intervention, immediately after intervention, and after 60 min. between- and within group-analysis was done using analysis of variance.

Results

Between-group analysis showed that neural tensioning was more effective than neural sliding in improving hamstring length on both measures, however this difference was negligible. Within-group analysis demonstrated that the mean post-test scores on the AKET test and SRT were significantly greater than the pre-test scores in both groups (p < 0 . 05 ). A reduction in the post-test scores was observed after 60 min, irrespective of the type of stretching (p < 0 . 05 ).

Conclusion

There was no difference in short-term effects of neural sliding or neural tensioning on hamstring flexibility in male recreational soccer players. Both groups showed improved flexibility immediately after the intervention with reduction in the effect after 60 min.

Effectiveness of neural mobilisation for the treatment of nerve-related cervicobrachial pain: a systematic review with subgroup meta-analysis

ABSTRACT

Neural mobilisations (NM) have been advocated for the treatment of nerve-related cervicobrachial pain; however, it is unclear what types of patients with nerve-related cervicobrachial pain (if any) may benefit. Medline, Web of Science, Scopus, PeDro, Cinahl, and Cochrane databases were searched from inception until December 2022. Randomised controlled trials were included if they assessed the effectiveness of NM in nerve-related cervicobrachial pain, and outcome measures were pain intensity and/or disability. Studies were classified according to their inclusion/exclusion criteria as radiculopathy , Wainner cluster , Hall , and Elvey cluster or other . Meta-analyses with subgroup analyses were performed. Risk of bias was assessed using Cochrane Rob2 tool. Twenty-seven studies were included. For pain and disability reduction, NM was found to be more effective than no treatment (pooled pain mean difference [MD] = -2.81, 95% confidence interval [CI] = -3.81 to -1.81; pooled disability standardized mean difference = -1.55, 95% CI = -2.72 to -0.37), increased the effectiveness of standard physiotherapy as an adjuvant when compared with standard physiotherapy alone (pooled pain MD = -1.44, 95% CI = -1.98 to -0.89; pooled disability MD = -11.07, 95% CI = -16.38 to -5.75) but was no more effective than cervical traction (pooled pain MD = -0.33, 95% CI = -1.35 to 0.68; pooled disability MD = -10.09, 95% CI = -21.89 to 1.81). For disability reduction, NM was found to be more effective than exercise (pooled MD = -18.27, 95% CI = -20.29 to -17.44). In most comparisons, there were significant differences in the effectiveness of NM between the subgroups. Neural mobilisations was consistently more effective than all alternative interventions (no treatment, traction, exercise, and standard physiotherapy alone) in 13 studies classified as Wainner cluster . PROSPERO registration: CRD42022376087.

Impact of the Order of Movement on the Median Nerve Root Function: A Neurophysiological Study with Implications for Neurodynamic Exercise Sequencing

Background: Neurodynamic exercise is a common clinical practice used to restore neural dynamic balance. The order in which movements are performed during these exercises is believed to play a crucial role in their effectiveness. This study aimed to investigate the impact of different sequences of neurodynamic exercise on nerve root function, with a specific focus on the median nerve. Methods: Participants were assigned randomly to three experimental groups, each undergoing a different test sequence: standard, proximal-to-distal, and distal-to-proximal. Dermatomal somatosensory evoked potentials (DSSEPs) were recorded at key levels (C6, C7, C8, and T1). Results: The findings revealed a significant influence of the movement sequence on DSSEP amplitudes. The execution of neurodynamic exercise in the proximal-to-distal sequence was associated with a notable reduction in amplitudes (p < 0.05). Conversely, the distal-to-proximal sequence resulted in increased amplitudes compared to the standard sequence (p < 0.05). Conclusions: This study underscores the importance of carefully considering the order of movements during neurodynamic exercising, particularly when evaluating nerve roots that lack the protective perineurium. The choice of sequence appears to have a substantial impact on nerve function, with implications for optimizing clinical neurodynamic exercise techniques.

Longitudinal Movements and Stiffness of Lower Extremity Nerves Measured by Ultrasonography and Ultrasound Elastography in Symptomatic and Asymptomatic Populations: A Systematic Review With Meta-analysis

This study was aimed at analyzing the effectiveness of ultrasonography (US) and ultrasound elastography (UE) in evaluating longitudinal sliding and stiffness of nerves. In line with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement, we analyzed 1112 publications (range: 2010-2021) extracted from MEDLINE, Scopus and Web of Science focusing on specific outcomes, including shear wave velocity (m/s), shear modulus (kPa), strain ratio (SR) and excursion (mm). Thirty-three papers were included and evaluated for overall quality and risk of bias. From the analysis of data concerning 1435 participants, mean shear wave velocity (SWV) in the sciatic nerve was 6.70 ± 1.26 m/s in controls and 7.51 ± 1.73 m/s in participants presenting with leg pain; in the tibial nerve, mean SWV was 3.83 ± 0.33 m/s in controls and 3.42 ± 3.53 m/s in participants presenting with diabetic peripheral neuropathy (DPN). The mean shear modulus (SM) was 20.9 ± 9.33 kPa for sciatic nerve, whereas it was an average of 23.3 ± 7.20 kPa for the tibial nerve. Considering 146 subjects (78 experimental, 68 controls) no significant difference was observed in SWV when comparing participants with DPN with controls (standard mean difference [SMD]: 1.26, 95% confidence interval [CI]: 0.54, 1.97), whereas a significant difference was observed in the SM (SMD: 1.78, 95% CI: 1.32, 2.25); furthermore, we found significant differences between left and right extremity nerves (SMD:1.14. 95% CI: 0.45, 1.83) among 458 participants (270 with DPN and 188 controls). No descriptive statistics are available for excursion because of the variability in participants and limb positions, whereas SR is considered only a semiquantitative outcome and therefore not comparable among different studies. Despite the presence of some limitations in study designs and methodological biases, on the basis of our findings, we can conclude that US and UE are effective methods in assessing longitudinal sliding and stiffness of lower extremity nerves in both symptomatic and asymptomatic subjects.

Acute effects of a single neurodynamic mobilization session on range of motion and H-reflex in asymptomatic young subjects: A controlled study

Neurodynamic techniques have yielded good clinical results in the treatment of various pathologies. The objective of this study is to examine the short-term effects of neurodynamic techniques of the sciatic nerve on hip ROM (range of motion) and on the amplitude and latency of the soleus H-reflex and M-waves, in young asymptomatic subjects. In a double-blind controlled trial design, 60 young asymptomatic participants were randomly assigned into six groups with different levels of manipulation of the sciatic nerve. The passive straight leg raise test was used to evaluate the hip ROM amplitude. All evaluations were performed before, 1 min after, and 30 min after intervention. For each time-point, spinal and muscle excitability were also tested. ROM increased in all groups, but none of the treatment groups had superior effects than the group with no treatment. This means that ROM testing maneuvers increased ROM amplitude, with no add-on effect of the proposed neurodynamic techniques. Neurophysiological responses changed similarly in all groups, showing that the aftereffects were not intervention-specific. We observed a significant negative association between the change in limb temperature and the change in latencies of all potentials. ROM-testing procedures performed repeatedly increase ROM amplitude. This observation should be considered when evaluating the aftereffects of therapeutic interventions on ROM amplitude. None of the explored neurodynamic techniques produced acute aftereffects on hip ROM amplitude, spinal or muscle excitability different to the induced by the ROM testing maneuver.

Effects of Neural Mobilization on Pain Intensity, Disability, and Mechanosensitivity: An Umbrella Review With Meta-Meta-Analysis

OBJECTIVE

The purpose of this study was to assess the current evidence for the effects of neural mobilization (NM) treatments.

METHODS

Three umbrella reviews with meta-meta-analyses were conducted to determine the effects of NM on pain intensity and disability in people with musculoskeletal disorders and on mechanosensitivity in participants who were asymptomatic. The study used the grading criteria proposed by the Physical Activity Guidelines Advisory Committee to assess the quality of evidence.

RESULTS

One meta-meta-analysis revealed a statistically significant moderate effect on pain intensity (standardized mean difference [SMD] = -0.75, 95% CI = -1.12 to -0.38) but with evidence of heterogeneity (Q = 14.13; I2 = 65%). The study found a significantly large effect of NM on disability (SMD = -1.22, 95% CI = -2.19 to -0.26), again with evidence of heterogeneity (Q = 31.57; I2 = 87%). The third meta-meta-analysis showed a statistically significant moderate effect of NM on mechanosensitivity (SMD = 0.96, 95% CI = 0.35 to 1.57), with no evidence of heterogeneity (Q = 2.73; I2 = 63%). For all examined outcomes, the quality of evidence was limited.

CONCLUSION

Overall, the results indicated that although NM treatment had a moderate to large beneficial clinical effect on pain intensity and disability in people with musculoskeletal disorders and on mechanosensitivity in individuals who were asymptomatic, the quality of evidence was limited.

IMPACT

Neural mobilization treatments showed positive results on the pain intensity and disability in individuals with musculoskeletal conditions. Neural mobilization could be integrated into the physical therapy management, although more research is needed.

Sciatic nerve movement in the deep gluteal space during hip rotations maneuvers

We hypothesize that the sciatic nerve in the subgluteal space has a specific behavior during internal and external coxofemoral rotation and during isometric contraction of the internal and external rotator muscles of the hip. In 58 healthy volunteers, sciatic nerve behavior was studied by ultrasound during passive internal and external hip rotation movements and during isometric contraction of internal and external rotators. Using MATLAB software, changes in nerve curvature at the beginning and end of each exercise were evaluated for longitudinal catches and axial movement for transverse catches. In the long axis, it was observed that during the passive internal rotation and during the isometric contraction of external rotators, the shape of the curve increased significantly while during the passive external rotation and the isometric contraction of the internal rotators the curvature flattened out. During passive movements in internal rotation, on the short axis, the nerve tended to move laterally and forward, while during external rotation the tendency of the nerve was to move toward a medial and backward position. During the isometric exercises, this displacement was less in the passive movements. Passive movements of hip rotation and isometric contraction of the muscles affect the sciatic nerve in the subgluteal space. Retrotrochanteric pain may be related to both the shear effect of the subgluteus muscles and the endoneural and mechanosensitive aggression to which the sciatic nerve is subjected.

Neurodynamics: is tension contentious?

Tensioning techniqueswere the first neurodynamic techniques used therapeutically in the management of people with neuropathies. This article aims to provide a balanced evidence-informed view on the effects of optimal tensile loading on peripheral nerves and the use of tensioning techniques. Whilst the early use of neurodynamics was centered within a mechanical paradigm, research into the working mechanisms of tensioning techniques revealed neuroimmune, neurophysiological, and neurochemical effects. In-vitro and ex-vivo research confirms that tensile loading is required for mechanical adaptation of healthy and healing neurons and nerves. Moreover, elimination of tensile load can have detrimental effects on the nervous system. Beneficial effects of tensile loading and tensioning techniques, contributing to restored homeostasis at the entrapment site, dorsal root ganglia and spinal cord, include neuronal cell differentiation, neurite outgrowth and orientation, increased endogenous opioid receptors, reduced fibrosis and intraneural scar formation, improved nerve regeneration and remyelination, increased muscle power and locomotion, less mechanical and thermal hyperalgesia and allodynia, and improved conditioned pain modulation. However, animal and cellular models also show that ‘excessive’ tensile forces have negative effects on the nervous system. Although robust and designed to withstand mechanical load, the nervous system is equally a delicate system. Mechanical loads that can be easily handled by a healthy nervous system, may be sufficient to aggravate clinical symptoms in patients. This paper aims to contribute to a more balanced view regarding the use of neurodynamics and more specifically tensioning techniques.

Assessing Sciatic Nerve Excursion and Strain with Ultrasound Imaging during Forward Bending

Entrapment neuropathies affecting the sciatic nerve tract may adversely affect neural biomechanical features such as excursion and strain. There is a paucity of in vivo evidence examining the effects of forward bending upon sciatic nerve excursion and strain. The purpose of this study was to assess the reliability of ultrasound imaging in measuring sciatic nerve excursion and strain during forward bending movements. Secondary aims were to quantify sciatic nerve excursion and strain during forward bending movements and to assess the relationship between sciatic nerve excursion and movements of the hip and lumbar spine. The reliability of measuring sciatic nerve excursion was high to excellent whilst measurement of sciatic nerve strain was moderate. The amount of hip flexion, during forward bending, was a strong predictor of sciatic nerve excursion. These findings will support clinicians in the assessment and treatment of entrapment neuropathies, in addition to providing a foundation for future research.

Sciatic nerve excursion during neural mobilization with ankle movement using dynamic ultrasound imaging: a cross-sectional study

PURPOSE

Ankle movement is used as a sensitizing maneuver for sciatica during neurodynamic techniques. In vivo studies on the sciatic nerve biomechanics associated with ankle movement during different positions of neighboring joints are scarce. The aim of this study was to investigate sciatic nerve excursion during ankle dorsiflexion in different positions in a healthy population.

METHODS

This is a cross-sectional study. High-resolution dynamic ultrasound imaging was used to measure longitudinal excursion of the sciatic nerve in the posterior thigh of 27 healthy participants during ankle dorsiflexion in six positions of the neck, hip, and knee. Both the long and short distance of the nerve excursion were measured. Wilcoxon signed-rank tests were used for data analysis, and Eta squared (r) was used to quantify the effect size.

RESULTS

Ankle dorsiflexion resulted in distal sciatic nerve excursion that was significantly higher in positions in which the knee was extended (median 0.7-1.6 mm) than in positions in which the knee was flexed (median 0.5-1.4 mm) (P ≤ 0.049, r ≥ 0.379). There were no significant differences in nerve excursion between positions where the neck was neutral compared with positions where the neck was flexed (P ≥ 0.710, r ≤ 0.072) or between positions where the hip was neutral compared with positions where the hip was flexed (P ≥ 0.456, r ≤ 0.143).

CONCLUSION

The positions of adjacent joints, particularly the knee, had an impact on the excursion of the sciatic nerve in the thigh during ankle movement.

The effect of different neural mobilization exercises on hamstring flexibility and functional flexibility in wrestlers

This study aimed to compare the short-term effects of sciatic nerve neural sliding and neural stretching exercises on hamstring muscle length and functional flexibility in wrestlers. The study participants included 74 wrestlers. The athletes were randomly divided into two groups: neural sliding and neural stretching groups. The hamstring flexibility and the functional flexibility were assessed using the active knee extension limitation (AKEL) angle and the sit and reach (SR) test one day before and immediately after the neural mobilization exercises, respectively. A three-way repeated measures analysis of variance was conducted that examined the effect of mobilization type, time, and gender on interest in AKEL right leg, AKEL left leg, and SR test. There is not a significant difference between the effect of two different mobilizations on AKEL right and left leg, and SR test (P>0.05). It was determined there is statistically significant differences between premobilization and post-mobilization outcome measures for AKEL right leg (F=59.886, P=0.001), AKEL left leg (F=31.896, P=0.001), and SR test (F=22.630, P=0.001). There is not a statistically significant difference between males and females by these three measures neural sliding and neural stretching exercises to the sciatic nerve in wrestlers were effective in increasing hamstring flexibility and functional flexibility and not superior to each other.

The immediate effect of neurodynamic techniques on jumping performance: A randomised double-blind study

BACKGROUND AND OBJECTIVES

Neurodynamic techniques are used to restore neural functions. However, there are few studies about the effects on performance. The aim of this study was to investigate the immediate effects on vertical jumping (VJ) and horizontal jumping (HJ) of 2 different tension loading techniques applied to young adults.

MATERIAL AND METHOD

In this randomised double-blind study, a total of 68 participants with a mean age of 21.31 ± 1.21 years were separated into 2 groups using the closed envelope system: the femoral nerve mobilization (FNM) group and the sciatic nerve mobilization (SNM) group. The FNM and SNM techniques were applied as 2 seconds stretching with 2 seconds resting for 10 repetitions. The VJ and HJ performance of the participants was evaluated before and after the interventions by a researcher blinded to the groups.

RESULTS

The mean VJ performance before and after interventions was measured as 34.56 ± 7.80 cm and 35.89 ± 8.15 cm in the FNM group (p< 0.05) and 31.74 ± 8.31 cm and 32.76 ± 8.45 cm in the SNM group (p< 0.05). The effects of the techniques on HJ performance were not statistically significant (p> 0.05). There was no superiority between the techniques (p> 0.05).

CONCLUSION

The neurodynamic techniques were found to provide an immediate increase in VJ performance. Neurodynamic techniques are generally used in patient populations to improve treatment outcomes. According to these study results, neurodynamic techniques can be safely used to provide an immediate increase in performances of individuals with no lower extremity problems.

Inadequacies of the Lasègue test, and how the Slump and Bowstring tests are useful for the diagnosis of sciatica

Diagnosis of sciatica mainly relies on pain reproduction by stretching of the lumbar roots since neurological examination and medical history are usually not sufficient to guarantee diagnosis. The Lasègue test is the most popular method, which starts with the straight leg-raising test (SLR). However it is not perfect, and is not always well performed or interpreted. Passive ankle dorsiflexion at the end of the SLR (Bragard test) is more sensitive, but can also remain normal in some cases of sciatica. Other stretching tests can help to recognise lumbar root damage in patients with poorly defined pain in a lower extremity: firstly, the Christodoulides test, i.e. reproduction of L5 sciatic pain by a femoral stretch test; secondly, the Slump test, performed on a patient in a sitting position, by slowly extending their painful leg then passively bending their neck (or the opposite); and thirdly, the Bowstring test, which requires, at the end of the Lasègue test, once the knee has been slightly flexed, pressing on the course of the peroneal and/or tibial nerves in the popliteal fossea to try and reproduce the exact pain felt by the patient. The combination of all these tests takes less than 2minutes, and could improve both the sensitivity and specificity of the physical examination for the diagnosis of sciatica. This article is a review of the limitations of the Lasègue/SLR tests and of the efficacy of these other tests for stretching the lumbar roots.

Neurodynamic sliders promote flexibility in tight hamstring syndrome

ABSTRACT Hamstring injury prevention puts emphasis on optimizing the muscle's strength-length relationship. To assure appropriate muscle length, flexibility training is imperative. As neurodynamics play an important role herein, the goal of this study was to explore the intervention effect of home-based neurodynamic slider program on hamstring flexibility. Fifty physically active male subjects were randomly assigned to either performing a neurodynamic sliding technique (3 × 20 reps) or a static stretching protocol (3 × 30″) on a daily basis for a 6-week period. Hamstring flexibility was assessed by means of the Straight Leg Raise at baseline, immediately after the intervention and after 4 weeks follow up. There was no between group baseline difference in hamstring flexibility. The repeated measure ANOVA showed a significant interaction effect for group × time (p < 0.001). Independent sample t-test showed a significantly higher increase in flexibility gain in the neurodynamic group immediately after the intervention (p < 0.001), as well as at 4 weeks retention analysis (p = 0.001) compared to the static stretch group. In conclusion, neurodynamic sliders might be more efficient than regular static stretching in affecting hamstring flexibility in the long run.

Acute effects of foam rolling on passive stiffness, stretch sensation and fascial sliding: A randomized controlled trial

PURPOSE

Foam Rolling (FR), aims to mimic the effects of manual therapy and tackle dysfunctions of the skeletal muscle and connective tissue. It has been shown to induce improvements in flexibility, but the underlying mechanisms are poorly understood. The aim of the present study was to further elucidate the acute, systemic and tissue-specific responses evoked by FR.

METHODS

In a crossover study, 16 (34 ± 6y, 6f) participants received all of the following interventions in a random order: a) 2 × 60 seconds of FR at the anterior thigh, b) 2 × 60 seconds of passive static stretching of the anterior thigh (SS), and c) no intervention (CON). Maximal active and passive knee flexion range of motion (ROM), passive stiffness, sliding of fascial layers, as well as knee flexion angle of first subjectively perceived stretch sensation (FSS) were evaluated before and directly after each intervention.

RESULTS

Flexibility increased only after, FR (active (+1.8 ± 1.9%) and passive ROM (+3.4 ± 2.7%), p = .006, respectively) and SS (passive ROM (+3.2 ± 3.5%), p = .002). Angle of FSS was altered following FR (+4.3° (95% CI: 1.4°-7.2°)) and SS (+6.7° (3.7°-9.6°)), while tissue stiffness remained unchanged after any intervention compared to baseline. Movement of the deepest layer (-5.7 mm (-11.3 mm to -0.1 mm)) as well as intrafascial sliding between deep and superficial layer (-4.9 mm (-9.mm to -0.7 mm)) decreased only after FR.

CONCLUSION

FR improved knee flexion ROM without altering passive stiffness, but modified the perception of stretch as well as the mobility of the deep layer of the fascia lata. The mechanisms leading to altered fascial sliding merit further investigation.

Mobilization of the contralateral limb in Slump position: effects on knee extension in healthy adult subjects

BACKGROUND AND AIM

In the acute phase of neuropathic pain due to nerve root disorders, the neurodynamic approach proposes the mobilization of the contralateral limb to decrease the pain and increase the range of motion in the affected limb. The aim of this study was to evaluate the effect of the contralateral knee mobilization on the ipsilateral knee extension range of motion in Slump position in healthy adult subjects.

METHODS

Thirty-eight healthy subjects underwent a placebo, control and experimental manoeuvres that included a passive contralateral knee mobilization into extension. The knee, hip and cervical angles and distance between glabella and femoral condyle achieved in Slump test position were measured with an optoelectronic motion analysis system before and after each manoeuvre.

RESULTS

Experimental manoeuvre produced a statistically significant increase of the knee extension ROM when compared to the control (p=.017) and placebo (p=.007) manoeuvres. A significant increase of the hip angle and distance between glabella and femoral condyle was detected after the experimental manoeuvres (p<.001), but not after the placebo and control manoeuvres.

CONCLUSIONS

The contralateral mobilization in Slump position increases the ipsilateral knee extension ROM. Further research is required to confirm that the knee increment ROM was due to the neural component.

Significance of epimuscular myofascial force transmission under passive muscle conditions

In the past 20 yr, force transmission via connective tissue linkages at the muscle belly surface, called epimuscular myofascial force transmission, has been studied extensively. In this article, the effects of epimuscular linkages under passive muscle conditions are reviewed. Several animal studies that included direct (invasive) measurements of force transmission have shown that different connective tissue structures serve as an epimuscular pathway and that these tissues have sufficient stiffness, especially at supraphysiological muscle lengths and relative positions, to transmit substantial passive forces (up to 15% of active optimal force). Exact values of lumped tissue stiffness for different connective tissue structures have not yet been estimated. Experiments using various imaging techniques (ultrasound, MRI, shear wave elastography) have yielded some, but weak, evidence of epimuscular myofascial force transmission for passive muscles in humans. At this point, the functional consequences of epimuscular pathways for muscle and joint mechanics in the intact body are still unknown. Potentially, however, these pathways may affect sensory feedback and, thereby, neuromuscular control. In addition, altered epimuscular force transmission in pathological conditions may also contribute to changes in passive range of joint motion.

The Variation of Cross-Sectional Area of the Sciatic Nerve in Flexion-Distraction Technique: A Cross-Sectional Study

OBJECTIVE

The purpose of this study was to compare the cross-sectional area of the sciatic nerve in different positions of spinal manipulation using flexion-distraction technique.

METHODS

Thirty healthy participants were assessed in 6 different flexion-distraction technique positions of varying lumbar, knee, and ankle positions. Participants stood in the following 3 positions with the lumbar in the neutral position: (A) with knee extended, (B) with knee flexed, and (C) with the knee extended and ankle dorsiflexion. Participants then stood in the following 3 positions with the lumbar flexed: (D) with the knee extended, (E) with the knee flexed, and (F) with knee extended and ankle dorsiflexion. The cross-sectional area (CSA) of the sciatic nerve was measured with ultrasound imaging in transverse sections in the posterior medial region of the left thigh. The CSA values measured at each position were compared.

RESULTS

We analyzed 180 ultrasound images. The cross-sectional area of the sciatic nerve (in mm²) in position B (mean; standard deviation) (59.71-17.41) presented a higher mean cross-sectional area value compared with position D (51.18-13.81; P =.005), position F (48.71-15.16; P = .004), and position C (48.37-16.35; P = .009).

CONCLUSION

The combination of knee extension and ankle dorsiflexion reduced the CSA of the sciatic nerve, and flexing the knee and keeping the ankle in the neutral position increased it.

Ultrasound Elastographic Measurement of Sciatic Nerve Displacement and Shear Strain During Active and Passive Knee Extension

There is current need for objective measures of sciatic nerve mobility in patients with sciatic-type pain. The objective of the study was to assess the feasibility and reliability of ultrasound elastography to quantify sciatic nerve displacement and shear strain at the sciatic nerve-hamstring muscle interface during active and passive knee extension-flexion exercises performed while sitting in healthy people. Ultrasound elastography showed excellent intrarater within-session reliability for assessing sciatic nerve displacement and sciatic nerve-hamstring muscle interface shear strain during active knee extension-flexion exercises. These findings will inform similar future work conducted in patients with sciatic-type pain.

Gemelli-obturator complex in the deep gluteal space: an anatomic and dynamic study

OBJECTIVE

To investigate the behavior of the sciatic nerve during hip rotation at subgluteal space.

MATERIALS AND METHODS

Sonographic examination (high-resolution ultrasound machine at 5.0-14 MHZ) of the gemelli-obturator internus complex following two approaches: (1) a study on cadavers and (2) a study on healthy volunteers. The cadavers were examined in pronation, pelvis-fixed position by forcing internal and external rotations of the hip with the knee in 90° flexion. Healthy volunteers were examined during passive internal and external hip rotation (prone position; lumbar and pelvic regions fixed). Subjects with a history of major trauma, surgery or pathologies affecting the examined regions were excluded.

RESULTS

The analysis included eight hemipelvis from six fresh cadavers and 31 healthy volunteers. The anatomical study revealed the presence of connective tissue attaching the sciatic nerve to the structures of the gemellus-obturator system at deep subgluteal space. The amplitude of the nerve curvature during rotating position was significantly greater than during resting position. During passive internal rotation, the sciatic nerve of both cadavers and healthy volunteers transformed from a straight structure to a curved structure tethered at two points as the tendon of the obturator internus contracted downwards. Conversely, external hip rotation caused the nerve to relax.

CONCLUSION

Anatomically, the sciatic nerve is closely related to the gemelli-obturator internus complex. This relationship results in a reproducible dynamic behavior of the sciatic nerve during passive hip rotation, which may contribute to explain the pathological mechanisms of the obturator internal gemellus syndrome.

Sciatic nerve stiffness is not changed immediately after a slump neurodynamics technique

Background

Neurodynamics techniques aim to assess and improve neural mechanosensitivity. However, there is no in vivo evidence regarding the mechanical effects of these techniques in the nerve stiffness. This study examined the immediate effects of a slump neurodynamics technique in the sciatic nerve shear wave velocity (SWV. i.e. an index of stiffness) using ultrasound-based elastography.

Methods

Fourteen healthy participants were included in this experiment. Sciatic SWV and ankle passive torque were measured during a passive ankle dorsiflexion motion (2°/s), before and immediately after 3 minutes of slump neurodynamics technique, randomly applied to one lower limb. The contralateral limb served as control.

Results

The slump intervention did not change the sciatic SWV (P=0.78), nor the dorsiflexion passive torque (P=0.14), throughout the ankle dorsiflexion motion. Excellent values of intra-rater repeatability (ICC=0.88, 0.68-0.96), and low values of standard error of measurement (0.59 m/s, 0.35-1.15m/s), were observed for the SWV measurements.

Conclusions

The sciatic nerve stiffness of healthy participants did not change immediately after a slump neurodynamics technique, suggesting a compliance of the neural tissue to tensile loads. However, these results ought to be confirmed using other neurodynamics techniques and in other populations (e.g. peripheral neuropathies).

Level of evidence

III.

Mechanical Coupling Between Muscle-Tendon Units Reduces Peak Stresses

The presence of mechanical linkages between synergistic muscles and their common tendons may distribute forces among the involved structures. We review studies, using humans and other animals, examining muscle and tendon interactions and discuss the hypothesis that connections between muscle bellies and within tendons may serve as a mechanism to distribute forces and mitigate peak stresses.

Assessing the Reliability of Ultrasound Imaging to Examine Peripheral Nerve Excursion: A Systematic Literature Review

Ultrasound imaging (USI) is gaining popularity as a tool for assessing nerve excursion and is becoming an important tool for the assessment and management of entrapment neuropathies. This systematic review aimed to identify current methods and report on the reliability of using USI to examine nerve excursion and identify the level of evidence supporting the reliability of this technique. A systematic search of five electronic databases identified studies assessing the reliability of using USI to examine nerve excursion. Two independent reviewers critically appraised and assessed the methodological quality of the identified articles. Eighteen studies met the eligibility criteria. The majority of studies were of "moderate" or "high" methodological quality. The overall analysis indicated a "strong" level of evidence of moderate to high reliability of using USI to assess nerve excursion. Further reliability studies with consistency of reporting are required to further strengthen the level of evidence.

In vivo effects of limb movement on nerve stretch, strain, and tension: A systematic review

BACKROUND

The mechanical behavior of the peripheral nervous system under elongation and tension has not been adequately established in vivo.

OBJECTIVE

The purpose of this review is to investigate the mechanical behavior of the peripheral nervous system in vivo.

METHODS

In vivo studies which evaluated the effects of limb movement and neurodynamic tests on peripheral nerve biomechanics were systematically searched in PubMed (Medline), the Cochrane Database, CINAHL, PEDro, Embase and Web of Science. Studies fulfilling the search criteria were assessed for methodological quality with a modified version of the Down & Blacks scale by two reviewers.

RESULTS

This review includes the results of 22 studies, of which 15 examined limb movement influencing the median nerve, four the sciatic nerve, two the tibial nerve; and one each the ulnar and peroneal nerves respectively. Substantial nerve longitudinal and transverse excursion and changes in diameter were reported. Despite this, increased nerve strain was not a major finding.

CONCLUSION

The heterogeneity of included studies, including wide variety of nerves tested, measurement location and joint position prevented comparisons between studies and also amalgamation of data. Limb movement induces complex biomechanical effects of which nerve elongation plays only a minor role.

The Effectiveness of Neural Mobilization for Neuromusculoskeletal Conditions: A Systematic Review and Meta-analysis

Study Design Systematic review with meta-analysis. Objectives To determine the efficacy of neural mobilization (NM) for musculoskeletal conditions with a neuropathic component. Background Neural mobilization, or neurodynamics, is a movement-based intervention aimed at restoring the homeostasis in and around the nervous system. The current level of evidence for NM is largely unknown. Methods A database search for randomized trials investigating the effect of NM on neuromusculoskeletal conditions was conducted, using standard methods for article identification, selection, and quality appraisal. Where possible, studies were pooled for meta-analysis, with pain, disability, and function as the primary outcomes. Results Forty studies were included in this review, of which 17 had a low risk of bias. Meta-analyses could only be performed on self-reported outcomes. For chronic low back pain, disability (Oswestry Disability Questionnaire [0-50]: mean difference, -9.26; 95% confidence interval [CI]: -14.50, -4.01; P<.001) and pain (intensity [0-10]: mean difference, -1.78; 95% CI: -2.55, -1.01; P<.001) improved following NM. For chronic neck-arm pain, pain improved (intensity: mean difference, -1.89; 95% CI: -3.14, -0.64; P<.001) following NM. For most of the clinical outcomes in individuals with carpal tunnel syndrome, NM was not effective (P>.11) but showed some positive neurophysiological effects (eg, reduced intraneural edema). Due to a scarcity of studies or conflicting results, the effect of NM remains uncertain for various conditions, such as postoperative low back pain, cubital tunnel syndrome, and lateral epicondylalgia. Conclusion This review reveals benefits of NM for back and neck pain, but the effect of NM on other conditions remains unclear. Due to the limited evidence and varying methodological quality, conclusions may change over time. Level of Evidence Therapy, level 1a. J Orthop Sports Phys Ther 2017;47(9):593-615. Epub 13 Jul 2017. doi:10.2519/jospt.2017.7117.

Acute effects of foam rolling on passive tissue stiffness and fascial sliding: study protocol for a randomized controlled trial

Background

Self-myofascial release (SMR) aims to mimic the effects of manual therapy and tackle dysfunctions of the skeletal muscle and connective tissue. It has been shown to induce improvements in flexibility, but the underlying mechanisms are still poorly understood. In addition to neuronal mechanisms, improved flexibility may be driven by acute morphological adaptations, such as a reduction in passive tissue stiffness or improved movement between fascial layers. The aim of the intended study is to evaluate the acute effects of SMR on the passive tissue stiffness of the anterior thigh muscles and the sliding properties of the associated fasciae.

Methods

In a crossover study design, 16 participants will receive all of the following interventions in a permutated random order: (1) one session of 2 × 60 s of SMR at the anterior thigh, (2) one session of 2 × 60 s of passive static stretching of the anterior thigh and (3) no intervention. Passive tissue stiffness, connective tissue sliding, angle of first stretch sensation, as well as maximal active and passive knee flexion angle, will be evaluated before and directly after each intervention.

Discussion

The results of the intended study will allow a better understanding of, and provide further evidence on, the local effects of SMR techniques and the underlying mechanisms for flexibility improvements.

Trial registration

ClinicalTrials.gov, identifier: NCT02919527. Registered on 27 September 2016.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-1866-y) contains supplementary material, which is available to authorized users.

A Randomised, Placebo-Controlled Trial of Neurodynamic Sliders on Hamstring Responses in Footballers with Hamstring Tightness

BACKGROUND

Neurodynamics intervention is known to increase apparent muscle extensibility, but information regarding hamstring responses after a neurodynamic sliders (NS) technique is scarce. The aim of this study was to evaluate the effects of NS on apparent hamstring extensibility and activity in footballers with hamstring tightness.

METHODS

Forty eligible healthy male footballers with hamstring tightness were each randomly allocated to either a 4-week NS technique or a control group (CG) receiving placebo shortwave intervention. Knee extension angles were measured with the passive knee extension test, and maximal voluntary isometric contraction (MVIC) of hamstrings was measured by a surface electromyography at baseline and after intervention sessions.

RESULTS

The results showed that NS produced a statistically and clinically significant increase in knee extension angle compared to CG (P < 0.001); however, there was no difference between the groups receiving MVIC of hamstrings. Within group comparison, NS also provided a significant increase in knee extension angle (P < 0.001), whereas the control group did not. There was no change in hamstring MVIC in either group after intervention.

CONCLUSIONS

The findings of this study reveal that four weeks of NS technique improved apparent hamstring extensibility but did not change the hamstring activity in footballers with hamstring tightness.

Neurodynamic treatment did not improve pain and disability at two weeks in patients with chronic nerve-related leg pain: a randomised trial

QUESTION

In people with nerve-related leg pain, does adding neurodynamic treatment to advice to remain active improve leg pain, disability, low back pain, function, global perceived effect and location of symptoms?

DESIGN

Randomised trial with concealed allocation and intention-to-treat analysis.

PARTICIPANTS

Sixty participants with nerve-related leg pain recruited from the community.

INTERVENTIONS

The experimental group received four sessions of neurodynamic treatment. Both groups received advice to remain active.

OUTCOME MEASURES

Leg pain and low back pain (0, none, to 10, worst), Oswestry Disability Index (0, none, to 100, worst), Patient-Specific Functional Scale (0, unable to perform, to 30, able to perform), global perceived effect (-5 to 5) and location of symptoms were measured at 2 and 4 weeks after randomisation. Continuous outcomes were analysed by linear mixed models. Location of symptoms was assessed by relative risk (95% CI).

RESULTS

At 2 weeks, the experimental group did not have significantly greater improvement than the control group in leg pain (MD -1.1, 95% CI -2.3 to 0.1) or disability (MD -3.3, 95% CI -9.6 to 2.9). At 4 weeks, the experimental group experienced a significantly greater reduction in leg pain (MD -2.4, 95% CI -3.6 to -1.2) and low back pain (MD -1.5, 95% CI -2.8 to -0.2). The experimental group also improved significantly more in function at 2 weeks (MD 5.2, 95% CI 2.2 to 8.2) and 4 weeks (MD 4.7, 95% CI 1.7 to 7.8), as well as global perceived effect at 2 weeks (MD 2.5, 95% CI 1.6 to 3.5) and 4 weeks (MD 2.9, 95% CI 1.9 to 3.9). No significant between-group differences occurred in disability at 4 weeks and location of symptoms.

CONCLUSION

Adding neurodynamic treatment to advice to remain active did not improve leg pain and disability at 2 weeks.

TRIAL REGISTRATION

NCT01954199. [Ferreira G, Stieven F, Araujo F, Wiebusch M, Rosa C, Plentz R, et al. (2016) Neurodynamic treatment did not improve pain and disability at two weeks in patients with chronic nerve-related leg pain: a randomised trial.Journal of Physiotherapy62: 197-202].

Limited mechanical effects of intermuscular myofascial connections within the intact rat anterior crural compartment

Skeletal muscles of the rat anterior crural compartment are mechanically connected by epimuscular myofascial connections, but the relevance for mechanical muscle function within physiological ranges of joint motion is unclear. We evaluated the net effect at the ankle joint of epimuscular myofascial connections between tibialis anterior (TA) and extensor digitorum longus (EDL) muscles in the rat (n=8) and determined which anatomical structures may mediate such epimuscular mechanical interactions. We assessed (1) effects of knee angle (i.e. changes in EDL length and position relative to TA) and interactions of knee angle with fasciotomy and proximal EDL tenotomy on TA ankle moment and (2) the effect of knee angle on TA and EDL ankle moment summation. Knee angle was varied between 60° and 130°. Ankle angle was kept constant (90°). TA and EDL were excited individually and simultaneously (TA&EDL). The mathematical sum of individual TA and EDL moments was compared with the moment exerted by TA&EDL to assess the extent of non-additive ankle moment summation. Magnitude of TA ankle moment was not affected by knee angle, but frontal plane moment direction was. However, dissections indicated that this was not caused by the compartmental fascia or EDL length changes. Moment summation was non-additive in magnitude (+1.1±1.1% mean±s.d.) and frontal plane direction. The latter was affected by knee angle and ranged from +0.2±0.3° at 60° to +1.1±0.6° at 130°. As the net effects found were very limited, we conclude that myofascial connections between muscles in the anterior crural compartment have limited mechanical relevance during normal movement.

Ultrasound assessment of fascial connectivity in the lower limb during maximal cervical flexion: technical aspects and practical application of automatic tracking

Background

The fascia provides and transmits forces for connective tissues, thereby regulating human posture and movement. One way to assess the myofascial interaction is a fascia ultrasound recording. Ultrasound can follow fascial displacement either manually or automatically through two-dimensional (2D) method. One possible method is the iterated Lucas-Kanade Pyramid (LKP) algorithm, which is based on automatic pixel tracking during passive movements in 2D fascial displacement assessments. Until now, the accumulated error over time has not been considered, even though it could be crucial for detecting fascial displacement in low amplitude movements.

The aim of this study was to assess displacement of the medial gastrocnemius fascia during cervical spine flexion in a kyphotic posture with the knees extended and ankles at 90°.

Methods

The ultrasound transducer was placed on the extreme dominant belly of the medial gastrocnemius. Displacement was calculated from nine automatically selected tracking points. To determine cervical flexion, an established 2D marker protocol was implemented. Offline pressure sensors were used to synchronize the 2D kinematic data from cervical flexion and deep fascia displacement of the medial gastrocnemius.

Results

Fifteen participants performed the cervical flexion task. The basal tracking error was 0.0211 mm. In 66 % of the subjects, a proximal fascial tissue displacement of the fascia above the basal error (0.076 mm ± 0.006 mm) was measured. Fascia displacement onset during cervical spine flexion was detected over 70 % of the cycle; however, only when detected for more than 80 % of the cycle was displacement considered statistically significant as compared to the first 10 % of the cycle (ANOVA, p < 0.05).

Conclusion

By using an automated tracking method, the present analyses suggest statistically significant displacement of deep fascia. Further studies are needed to corroborate and fully understand the mechanisms associated with these results.

Assessing the Reliability of Ultrasound Imaging to Examine Radial Nerve Excursion

Ultrasound imaging allows cost effective in vivo analysis for quantifying peripheral nerve excursion. This study used ultrasound imaging to quantify longitudinal radial nerve excursion during various active and passive wrist movements in healthy participants. Frame-by-frame cross-correlation software allowed calculation of nerve excursion from video sequences. The reliability of ultrasound measurement of longitudinal radial nerve excursion was moderate to high (intraclass correlation coefficient range = 0.63-0.86, standard error of measurement 0.19-0.48). Radial nerve excursion ranged from 0.41 to 4.03 mm induced by wrist flexion and 0.28 to 2.91 mm induced by wrist ulnar deviation. No significant difference was seen in radial nerve excursion during either wrist movement (p > 0.05). Wrist movements performed in forearm supination produced larger overall nerve excursion (1.41 ± 0.32 mm) compared with those performed in forearm pronation (1.06 ± 0.31 mm) (p < 0.01). Real-time ultrasound is a reliable, cost-effective, in vivo method for analysis of radial nerve excursion.

The effect of spinal position on sciatic nerve excursion during seated neural mobilisation exercises: an in vivo study using ultrasound imaging

Objectives

Research has established that the amount of inherent tension a peripheral nerve tract is exposed to influences nerve excursion and joint range of movement (ROM). The effect that spinal posture has on sciatic nerve excursion during neural mobilisation exercises has yet to be determined. The purpose of this research was to examine the influence of different sitting positions (slump-sitting versus upright-sitting) on the amount of longitudinal sciatic nerve movement during different neural mobilisation exercises commonly used in clinical practice.

Methods

High-resolution ultrasound imaging followed by frame-by-frame cross-correlation analysis was used to assess sciatic nerve excursion. Thirty-four healthy participants each performed three different neural mobilisation exercises in slump-sitting and upright-sitting. Means comparisons were used to examine the influence of sitting position on sciatic nerve excursion for the three mobilisation exercises. Linear regression analysis was used to determine whether any of the demographic data represented predictive variables for longitudinal sciatic nerve excursion.

Results

There was no significant difference in sciatic nerve excursion (across all neural mobilisation exercises) observed between upright-sitting and slump-sitting positions (P = 0.26). Although greater body mass index, greater knee ROM and younger age were associated with higher levels of sciatic nerve excursion, this model of variables offered weak predictability (R² = 0.22).

Discussion

Following this study, there is no evidence that, in healthy people, longitudinal sciatic nerve excursion differs significantly with regards to the spinal posture (slump-sitting and upright-sitting). Furthermore, although some demographic variables are weak predictors, the high variance suggests that there are other unknown variables that may predict sciatic nerve excursion. It can be inferred from this research that clinicians can individualise the design of seated neural mobilisation exercises, using different seated positions, based upon patient comfort and minimisation of neural mechanosensitivity with the knowledge that sciatic nerve excursion will not be significantly influenced.

Non-invasive assessment of sciatic nerve stiffness during human ankle motion using ultrasound shear wave elastography

Peripheral nerves are exposed to mechanical stress during movement. However the in vivo mechanical properties of nerves remain largely unexplored. The primary aim of this study was to characterize the effect of passive dorsiflexion on sciatic nerve shear wave velocity (an index of stiffness) when the knee was in 90° flexion (knee 90°) or extended (knee 180°). The secondary aim was to determine the effect of five repeated dorsiflexions on the nerve shear wave velocity. Nine healthy participants were tested. The repeatability of sciatic nerve shear wave velocity was good for both knee 90° and knee 180° (ICCs ≥ 0.92, CVs ≤ 8.1%). The shear wave velocity of the sciatic nerve significantly increased (p<0.0001) during dorsiflexion when the knee was extended (knee 180°), but no changes were observed when the knee was flexed (90°). The shear wave velocity-angle relationship displayed a hysteresis for knee 180°. Although there was a tendency for the nerve shear wave velocity to decrease throughout the repetition of the five ankle dorsiflexions, the level of significance was not reached (p=0.055). These results demonstrate that the sciatic nerve stiffness can be non-invasively assessed during passive movements. In addition, the results highlight the importance of considering both the knee and the ankle position for clinical and biomechanical assessment of the sciatic nerve. This non-invasive technique offers new perspectives to provide new insights into nerve mechanics in both healthy and clinical populations (e.g., specific peripheral neuropathies).

Effects of epimuscular myofascial force transmission on sarcomere length of passive muscles in the rat hindlimb

Results from imaging studies and finite element models suggest epimuscular myofascial effects on sarcomere lengths in series within muscle fibers. However, experimental evidence is lacking. We evaluated epimuscular myofascial effects on (1) muscle belly, fiber, and mean sarcomere length and (2) sarcomere length distribution within passive fibers of the rat tibialis anterior (TA) and soleus (SO) muscles. Hindlimbs (n = 24) were positioned in predefined knee (55°, 90°, 125°, 160°) and ankle (either 90° or 125°) angles, and fixed in a formaldehyde solution. Varying knee joint angle causes changes in muscle–tendon unit length of SO and TA’s synergists, but not of SO and TA. Whole fibers were taken from SO and TA and photographed along their length. Mean sarcomere length was assessed for the entire fiber and for the proximal, intermediate, and distal thirds (fiber segments) separately. Mean sarcomere length of the fiber was not affected by knee angle, neither for SO (mean: 2.44 ± 0.03 μm and 2.19 ± 0.05 μm for ankle angles of 90° and 125°, respectively) nor for TA (mean: 2.33 ± 0.05 μm and 2.51 ± 0.07 μm for ankle angle set to 90° and 125°, respectively). Only for TA, a significant interaction between knee angle and fiber segment was found, indicating changes in the distribution of lengths of in-series sarcomeres. Thus, while epimuscular myofascial force transmission did not cause mean sarcomere length changes within passive SO and TA, it did alter the length distribution of sarcomeres within passive TA.

Excursion of the Sciatic Nerve During Nerve Mobilization Exercises: An In Vivo Cross-sectional Study Using Dynamic Ultrasound Imaging

STUDY DESIGN

Controlled laboratory cross-sectional study using single-group, within-subject comparisons.

OBJECTIVES

To determine whether different types of neurodynamic techniques result in differences in longitudinal sciatic nerve excursion.

BACKGROUND

Large differences in nerve biomechanics have been demonstrated for different neurodynamic techniques for the upper limb (median nerve), but recent findings for the sciatic nerve have only revealed small differences in nerve excursion that may not be clinically meaningful.

METHODS

High-resolution ultrasound imaging was used to quantify longitudinal sciatic nerve movement in the thigh of 15 asymptomatic participants during 6 different mobilization techniques for the sciatic nerve involving the hip and knee. Healthy volunteers were selected to demonstrate normal nerve biomechanics and to eliminate potentially confounding variables associated with dysfunction. Repeated-measures analyses of variance were used to analyze the data.

RESULTS

The techniques resulted in markedly different amounts of nerve movement (P<.001). The tensioning technique was associated with the smallest excursion (mean ± SD, 3.2 ± 2.1 mm; P < or = .004). The sliding technique resulted in the largest excursion (mean ± SD, 17.0 ± 5.2 mm; P<.001), which was approximately 5 times larger than that resulting from the tensioning technique and, on average, twice as large as that resulting from individual hip or knee movements.

CONCLUSION

Consistent with current theories and findings for the median nerve, different neurodynamic exercises for the lower limb resulted in markedly different sciatic nerve excursions. Considering the continuity of the nervous system, the movement and position of adjacent joints have a large impact on nerve biomechanics.

Onset and maximum values of electromyographic amplitude during prone hip extension after neurodynamic technique in patients with lumbosciatic pain: A pilot study

OBJECTIVE

The mechanisms underlying the effects of neurodynamic techniques are still unknown. Therefore, the aim of this study was to provide a starting point for future research on explaining why neurodynamic techniques affect muscular activities in patients with sciatic pain.

METHODS

A double-blind trial was conducted in 12 patients with lumbosciatica. Surface electromyography activity was assessed for different muscles during prone hip extension. Pre- and post-intervention values for muscle activity onset and maximal amplitude signals were determined.

RESULTS

There was a significant reduction in the surface electromyography activity of maximal amplitude in the erector spinae and contralateral erector spinae (p < 0.05). Additionally, gluteus maximus (p < 0.05) activity onset was delayed post-intervention.

CONCLUSIONS

Self-neurodynamic sliding techniques modify muscular activity and onset during prone hip extension, possibly reducing unnecessary adaptations for protecting injured components. Future work will analyze the effects of self-neurodynamic sliding techniques during other physical tasks.

Short term effectiveness of neural sliders and neural tensioners as an adjunct to static stretching of hamstrings on knee extension angle in healthy individuals: A randomized controlled trial

OBJECTIVE

To investigate the added benefit of nerve-biased interventions over static stretching in hamstring flexibility and to compare the effectiveness of two types of nerve-biased interventions over a week.

DESIGN

Three-arm assessor-blinded randomized controlled trial.

SETTING

University Laboratory.

PARTICIPANTS

Sixty healthy individuals (mean age = 22 ± 2.4 years) with reduced hamstring flexibility were randomized to three groups who received static stretching and neurodynamic sliders (NS-SS); static stretching with neurodynamic tensioner (NT-SS) and static stretching (SS) alone.

OUTCOME MEASURE

Knee extension angle (KEA) in degrees.

RESULTS

Baseline characteristics including demographic, anthropomorphic and KEA between groups were comparable. A significant interaction was observed between group (intervention) and time, [F (2,114) = 3.595; p = 0.031]. Post-hoc pairwise comparisons analyses revealed significant differences at post-intervention measurement time point between NS-SS and SS (mean difference: -6.8; 95%CI = -12, -1.5; p = 0.011) and NT-SS and SS (mean difference: -11.6; 95%CI = -16.7, -6.3; p < 0.001). However there was no significant difference between NS-SS and NT-SS groups (mean difference: 4.8; 95%CI = 0.4, 9.9; p = 0.074).

CONCLUSIONS

Neural sliders and tensioners are both effective in increasing hamstring flexibility as an adjunct to static hamstring stretching when compared to static stretching alone. No neural mobilization technique proved to be superior over another.

CLINICAL TRIAL REGISTRATION

This clinical trial is registered in Clinical Trials Registry- India (CTRI) with registration number CTRI/2012/05/002619.

No functionally relevant mechanical effects of epimuscular myofascial connections between rat ankle plantar flexors

Triceps surae muscles are mechanically connected by the shared Achilles tendon and by epimuscular myofascial connections. We aimed to assess effects of proximal lengthening of gastrocnemius (GA) and plantaris muscles, imposed by changes in knee angle, on (i) the magnitude and direction of the 3D ankle moment exerted by the soleus (SO) muscle, and on (ii) mechanical interaction between ankle plantar flexor muscles during co-activation of GA muscle, in the rat (n=9). Ankle angle was kept constant (90°), while knee angle was varied between 60° and 130°. At each knee angle, SO was excited individually as well as simultaneously with GA (SO&GA). The mathematical sum of individual SO and GA ankle moments was compared with the ankle moment exerted by SO&GA to assess nonlinear summation. Knee angle did not affect the magnitude of the SO ankle moment (p=0.695). Moment directions in the transverse (p=0.050) and frontal (p=0.008) planes were affected by knee angle, but dissection indicated that this was not caused by length changes of the two-joint synergistic muscles. Nonlinear summation was found in the magnitude (-1.4±1.9%, mean±s.d., p&lt;0.001) and in the frontal plane vector direction of the ankle moment (0.13±0.23°, p=0.003), however, the extent did not change with knee angle. While SO&GA contraction increased Achilles tendon length compared to rest, this length was not knee angle dependent (p=0.649). Despite that intermuscular force transmission per se cannot be excluded, we conclude that in vivo the mechanical effects of epimuscular myofascial connections between rat ankle plantar flexors are not functionally relevant.

Quantitative in vivo longitudinal nerve excursion and strain in response to joint movement: A systematic literature review

BACKGROUND

Neural system mobilization is widely used in the treatment of several painful conditions. Data on nerve biomechanics is crucial to inform the design of mobilization exercises. Therefore, the aim of this review is to characterize normal nervous system biomechanics in terms of excursion and strain.

METHODS

Studies were sought from Pubmed, Physiotherapy Evidence Database, Cochrane Library, Web of Science and Scielo. Two reviewers' screened titles and abstracts, assessed full reports for potentially eligible studies, extracted information on studies' characteristics and assessed its methodological quality.

FINDINGS

Twelve studies were included in this review that assessed the median nerve (n=8), the ulnar nerve (n=1), the tibial nerve (n=1), the sciatic nerve (n=1) and both the tibial and the sciatic nerves (n=1). All included studies assessed longitudinal nerve excursion and one assessed nerve strain. Absolute values varied between 0.1mm and 12.5mm for median nerve excursion, between 0.1mm and 4.0mm for ulnar nerve excursion, between 0.7 mm and 5.2mm for tibial nerve excursion and between 0.1mm and 3.5mm for sciatic nerve excursion. Maximum reported median nerve strain was 2.0%.

INTERPRETATION

Range of motion for the moving joint, distance from the moving joint to the site of the lesion, position of adjacent joints, number of moving joints and whether joint movement stretches or shortens the nerve bed need to be considered when designing neural mobilization exercises as all of these factors seem to have an impact on nerve excursion.