Mechanosensitivity of the Lower Extremity Nervous System During Straight-Leg Raise Neurodynamic Testing in Healthy Individuals

Abstract

respond to the mechanical stresses imposed upon them during movement. 27 Neurodynamic tests are used to assess the nervous system's mechanosensitivity through monitoring the response to movements that are known to alter the mechanical stresses acting on the nervous system. The most common lower quarter neurodynamic test is the passive straight-leg raise (SLR) test. 13,31 The basic SLR test consists of the tester performing passive hip flexion, with the patient in a supine position and the knee held in full extension. 9A recent systematic review of SLR testing indicated a lack of standardization, including the use of various criteria for determining the test end point. 31 The authors of this review reintroduced standardized methodology proposed by Breig and Troup 8 in 1979, including the use of the first onset of pain as the end point during the SLR test.31 Despite these recommendations, alternative end points, such as maximally tolerated symptom, are still utilized.17 Because SLR testing is performed in both symptomatic and C linical neurological examinations are an integral part of clinical decision making for determining neural involvement in individuals with altered physical function and activity participation. One aspect of a standard neurological examination involves assessing the sensitivity of peripheral nerves to limb movement, termed mechanosensitivity. Mechanosensitivity is thought to be a normal protective mechanism that allows the nerves to t STudy deSiGn: Cross-sectional, observational study.t objecTiveS: To explore how ankle position affects lower extremity neurodynamic testing. t backGround: Upper extremity limb movements that increase neural loading create a protective muscle action of the upper trapezius, resulting in shoulder girdle elevation during neurodynamic testing. A similar mechanism has been suggested in the lower extremities.t meThodS: Twenty healthy subjects without low back pain participated in this study. Hip flexion angle and surface electromyographic measures were taken and compared at the onset of symptoms (P1) and at the point of maximally tolerated symptoms (P2) during straight-leg raise tests performed with ankle dorsiflexion (DF-SLR) and plantar flexion (PF-SLR).t reSuLTS: Hip flexion was reduced during DF-SLR by a mean  SD of 5.5°  6.6° at P1 (P = .001) and 10.1°  9.7° at P2 (P.001), compared to PF-SLR. DF-SLR induced distal muscle activation and broader proximal muscle contractions at P1 compared to PF-SLR. t concLuSion: These findings support the hypothesis that addition of ankle dorsiflexion during straight-leg raise testing induces earlier distal muscle activation and reduces hip flexion motion. The straight-leg test, performed to the onset of symptoms (P1) and with sensitizing maneuvers, allows for identification of meaningful differences in test outcomes and is an appropriate end point for lower extremity neurodynamic testing.

Manual therapy and neurodynamic mobilization in a patient with peroneal nerve paralysis: a case report

“…11,[21][22][23] According to Nee and Butler (2006), cited in Boyd et al, 24 the criteria for interpretation of neurodynamic testing include whether the test (a) reproduces the symptoms, (b) identifies a significant deviation from normal, or (c) produces alterations in the symptoms by adding in a distal joint movement, also called sensitizing movements. 24 For example, muscle EMG activity, location of symptoms, and hip motions are altered when performing 2 sensitizing versions of the straight leg raise maneuver, assisting clinicians to Fig 3. A, Proximal slider, a straight leg raise and application of plantar-flexion without producing symptoms. B, Distal slider; during the phase in which the leg is flexed, the foot is dorsiflexed.…”

“…detect meaningful clinical differences in relation to tension in the neural structures. 24,25 It has been postulated that NM may produce its effects by increasing axoplasmic flow, improving intraneural swelling, and reducing pressure and inflammation in neural tissue. 26,27 In addition, previous studies have demonstrated that neural provocation tests produce statistically significant increases of muscle activity compared to resting levels in the upper and lower limb.…”

“…26,27 In addition, previous studies have demonstrated that neural provocation tests produce statistically significant increases of muscle activity compared to resting levels in the upper and lower limb. 24,28 Neural mobilization is currently being used to reduce spasticity in individuals suffering from neurological disorders 29 ; for example, NM can reduce EMG activity in the biceps brachii muscle in patients with stroke. 30 The results of this case also align with previous studies showing improvement in motor effects via EMG activity and reduction in pain produced by neural mobilization in the upper limb.…”

Neurodynamic Responses to the Femoral Slump Test in Patients With Anterior Knee Pain Syndrome

“…Because of the possible links between anterior knee pain and deficits in lower extremity muscle strength and flexibility, and the potential impact of muscle activation and flexibility problems on the results of neurodynamic testing, 1,4,13,15,16 a series of physical examinations for lower extremity flexibility, strength, and alignment, as well as functional testing and the general ligamentous laxity test, were conducted. This ensured that lower extremity flexibility or strength did not interfere with the results of the FST.…”

“…2,13 To determine whether neurodynamic responses contribute to the occurrence of clinical symptoms, a structure differential maneuver, such as neck flexion/extension, could be added to further change the stress on the neural tissues in question, while minimizing the movement of the musculoskeletal tissues in the target region. 1,[2][3][4]10,15 In patients, the T T STUDY DESIGN: Matched-control, crosssectional study.…”