Upper Limb Neurodynamic Test 1 Research Articles

Effect of cervical contralateral lateral flexion on the median nerve and fascia at the wrist – Cadaveric study

BackgroundNeurodynamic tests are an essential aspect of the physical examination of the patient when suspicion of neural involvement exists. A manoeuvre that is hypothesised to move nerves differentially relative to other structures (structural differentiation) has been proposed as a necessary part of neurodynamic testing for differential diagnosis. However, although the specificity of structural differentiation for peripheral nerve over muscle has been demonstrated in some body regions, no study has tested specificity of nerve movement relative to fascia. ObjectivesThe aim of this study was to measure the effect of the cervical contralateral lateral flexion (CCLF) as an structural differentiation manoeuvre for the median nerve compared to fascia (superficial and deep) at the wrist during the upper limb neurodynamic test 1 (ULNT1). DesignA cross-sectional study was performed in 5 fresh frozen cadavers. MethodsExcursion and strain in the fascia (superficial and deep) and the median nerve were measured at the wrist with structural differentiation during the ULNT1. KINOVEA software was used to measure kinematic parameters. ResultsCCLF resulted in significant proximal excursion in the median nerve (p < 0.001*) but not in the strain. CCLF neither produced changes in strain nor excursion in the superficial and deep fascia (p > 0.05). ConclusionThis study showed that CCLF produced significant differential excursion in the median nerve at the wrist compared to the local superficial and deep fascia during the ULNT1. The data support CCLF in mechanical differentiation between nerve and fascia in this area in diagnosis of local sources of wrist pain.

Effectiveness of Deep Cervical Fascial Manipulation® and Sequential Yoga Poses on Pain and Function in Individuals with Mechanical Neck Pain: A Randomised Controlled Trial.

This study aimed to investigate the effect of fascial manipulation (FM) of the deep cervical fascia (DCF) and sequential yoga poses (SYP) on pain and function in individuals with mechanical neck pain (MNP). Following the predefined criteria, ninety-nine individuals with MNP were recruited, randomised, and assigned to either the intervention group (IG) (n = 51) or the control group (CG) (n = 48). Individuals in the IG received FM (4 sessions in 4 weeks) and the home-based SYP (4 weeks). The CG participants received their usual care (cervical mobilisation and thoracic manipulation (4 sessions in 4 weeks) along with unsupervised therapeutic exercises (4 weeks). The participants underwent baseline and weekly follow-up measurements of pain using a numerical pain rating scale (NPRS) and elbow extension range of motion (EEROM) during the upper limb neurodynamic test 1 (ULNT1). The baseline and the fourth session follow-up measurements of the patient-specific functional scale (PSFS) and fear-avoidance behavior Questionnaire (FABQ) were also taken. A repeated-measures ANOVA was performed. There were statistically significant differences between the IG and CG on the NPRS third and fourth sessions, with mean differences (MD) of -1.009 (p < 0.05) and -1.701 (p < 0.001), respectively. Regarding EEROM, there was a 20.120° difference (p < 0.001) in the fourth session between the groups. The MD in FABQ was -5.036 (p < 0.001), but there were no significant differences in PSFS between the groups during the follow-up. FM and SYP can aid in reducing pain and fear-avoidance behaviour and improve the function and extensibility of the upper quarter region.

Quantifying the Elasticity Properties of the Median Nerve during the Upper Limb Neurodynamic Test 1.

Background The upper limb neurodynamic test 1 (ULNT1) consists of a series of movements that are thought to detect an increase in neuromechanical sensitivity. In vivo, no trail was made to quantify the association between the nerve elasticity and different limb postures during ULNT1. Objectives (1) To investigate the relationship between nerve elasticity and limb postures during ULNT1 and (2) to investigate the intra- and interoperator reliabilities of shear wave elastography (SWE) in quantifying the elasticity of median nerve. Methods Twenty healthy subjects (mean age: 19.9 ± 1.4 years old) participated in this study. The median nerve was imaged during elbow extension in the following postures: (1) with neutral posture, (2) with wrist extension (WE), (3) with contralateral cervical flexion (CCF), and (4) with both WE and CCF. The intra- and interoperator reliabilities measured by two operators at NP and CCF+WE and intraclass correlation coefficients (ICCs) were calculated. Results The intraoperator (ICC = 0.72–0.75) and interoperator (ICC = 0.89–0.94) reliabilities for measuring the elasticity of the median nerve ranged from good to excellent. The mean shear modulus of the median nerve increased by 53.68% from NP to WE+CCF. Conclusion SWE is a reliable tool to quantify the elasticity of the median nerve. There was acute modulation in the elasticity of the median nerve during the ULNT1 when healthy participants reported substantial discomfort. Further studies need to focus on the elasticity properties of the median nerve in patients with peripheral neuropathic pain.

Neurodynamic Functions and Their Correlations with Postural Parameters in Adolescents with Idiopathic Scoliosis.

Knowledge about neurodynamic functions of the nervous system (NS) in patients with idiopathic scoliosis (IS) is limited. This study aimed to assess the mechanosensitivity of the NS structures (MNS) in adolescents with IS. The study included 69 adolescents with IS and 57 healthy peers aged 10–15 years. The Upper Limb Neurodynamic Test 1 (ULNT1), straight leg raise (SLR) test, and slump test (SLUMP) were used to assess MNS. The spinal curvatures in the sagittal plane and selected ranges of motion were measured. The data were analysed using the Mann–Whitney U test and Spearman’s rank correlation. Increased MNS assessed by ULNT1 and SLUMP tests was observed in participants with IS. Values of the neurodynamic tests correlated significantly with the sagittal profile of the spine and the mobility of the spine and lower limbs in both groups. In conclusion, increased MNS occurs in adolescents with IS. Therefore, the examination of adolescents with IS should include an assessment of MNS with the neurodynamic tests. Future studies should investigate this issue to better understand the mechanisms that coexist with IS.

Median Nerve Neural Mobilization Adds No Additional Benefit When Combined with Cervical Lateral Glide in the Treatment of Neck Pain: A Randomized Clinical Trial.

Background: This study aimed to compare the effectiveness of cervical lateral glide (CLG) added to median nerve neural mobilization (MNNM) in patients with neck pain (NP). Methods: A single-blinded randomized controlled clinical trial was carried out in a Pain Management Unit from a Hospital. A total sample of 72 patients with NP was recruited from a hospital. Patients were randomized to receive isolated CLG (n = 36) or CLG + MNNM (n = 36). Bilateral elbow extension range of motion (ROM) on upper limb neurodynamic test 1 (ULNT1), bilateral pressure pain thresholds (PPT) on the median nerve at elbow joint, C6 zygapophyseal joint and tibialis anterior, Visual analogue scale (VAS), body chart distribution of pain, active cervical ROM (CROM), Neck Disability Index (NDI), and Tampa Scale of Kinesiophobia (TSK-11) were measured at baseline as well as immediately, 15 days, and 1 month after treatment. Results: There were no statistically significant interactions (p > 0.05) between treatment and time for median nerve mechanosensitivity outcomes, pain intensity, symptom distribution, and PPT of the widespread pain assessment, as well as cervical function, and kinesiophobia. Conclusions: MNNM gave no additional benefit to CLG in patients with NP regarding pain intensity, symptom distribution, mechanosensitivity, functionality, and kinesiophobia. Only two treatment sessions and the short follow-up are important issues, therefore, justifying further studies to answer the research question with better methodology.

PND3 Patient-Reported Outcomes Following Neuromanual Therapy For Carpal Tunnel Syndrome- Comparison Of Four Patient & Healthcare Outcome Measures In A Randomized Clinical Trial

To investigate the prognostic utility of four patient-reported outcome measures in evaluating therapeutic effectiveness following Neuromanual therapy (NMT) for adults with Carpal tunnel syndrome (CTS). 42 working age adults (29 male, 13 female) with mean age 41.26 12.18 years, participated in an observer-blinded randomized clinical trial with concealed treatment allocation. The participants were randomly assigned to receive control intervention in group-1: standard care physical therapy- therapeutic ultrasound, carpal bone mobilization and hand exercises, or experimental intervention in group-2: NMT comprising of median nerve massage and slider techniques. Treatments were given for 45 mins duration, thrice weekly for three weeks. The four questionnaires: Carpal Tunnel Syndrome Questionnaire (CTSQ), Quick- Disabilities of Arm, Shoulder and Hand (DASH), Patient-Rated Wrist Evaluation (PRWE), and Boston Carpal Tunnel Questionnaire (BCTQ) were correlated with pain-free grip strength (by Jamar hand dynamometer), pain intensity on 10cm Visual analogue scale and clinical test for median nerve mobility (by Upper limb neurodynamic test-1: ULNT-1) measured in range of motion (ROM) using a goniometer. Within-group and between-group comparisons of outcome measures were performed using students' t-test at 95% confidence interval using SPSS version 22 for Windows software. Statistically significant (p<.05) improvements were detected by CTSQ for disease-specific outcomes (pre-post difference 26.14± 8.2) which correlated (r=.76) with ULNT-1 ROM confirming the criterion-related validity. CTSQ was an useful prognostic outcome measure for CTS following NMT interventions in the adults as found in this study.

Immediate effects of acupuncture on the mechanosensitivity of the median nerve: an exploratory randomised trial.

Acupuncture appears to reduce the mechanosensitivity of peripheral nerves in animal models; yet, this possibility has not been demonstrated in humans. The main objective of this exploratory trial was to evaluate the immediate effects of acupuncture on the mechanosensitivity of the median nerve, measured by the elbow extension range-of-motion (EE-ROM) at pain onset and maximum tolerance during the upper limb neurodynamic test 1 (ULNT1). Additional objectives were to test the effects of two different points in ULNT1 responses and critically appraise pre-/post-intervention changes for conducting future research. Thirty-one asymptomatic individuals, randomly assigned to the PC group (n=14) or the LU group (n=17) by the coin flip procedure, underwent acupuncture (leopard spot needling) at PC5 or LU5'', respectively. Two-way mixed-model analysis of variance (ANOVA) with time (pre-intervention vs post-intervention) as the within-subject factor and group (PC vs LU) as the between-subject factor, plus time×group interaction, were used to determine the effects of acupuncture therapy on EE-ROM at pain onset and maximum tolerance during ULNT1. At baseline there were no differences between groups (p>0.05). After acupuncture, mean EE-ROM increased 3.1° at pain onset (p=0.029, η2p=0.154) and 5.6° at maximum tolerance (p=0.002, η2p=0.277) with no differences between groups (p>0.05, η2p<0.01). Immediately after acupuncture, the mechanosensitivity of the median nerve appears to be reduced as observed by an increase in EE-ROM during the ULNT1. Further studies are needed to confirm these preliminary findings. NCT02150915; Post-results.

Comparison of Median Nerve Mechanosensitivity and Pressure Pain Threshold in Patients With Nonspecific Neck Pain and Asymptomatic Individuals

ObjectiveThe purpose of this study was to investigate the presence of median nerve mechanosensitivity by comparing median nerve neurodynamic test results of patients with nonspecific neck pain (NNP) and asymptomatic individuals. MethodsA total of 40 patients (30 women, 10 men) with NNP between the ages of 21 and 62 years (39.53 ± 10.18 years) and 38 asymptomatic individuals (23 women, 15 men) between the ages of 18 and 60 years (37.13 ± 9.64 years) participated in the study. Pressure pain threshold was assessed with digital pressure algometer, cervical joint range of motion was assessed with a universal goniometer, and median nerve mechanosensitivity was assessed with Upper Limb Neurodynamic Test 1 (ULNT1). The test step where the first sensory response was given, the location and character of the sensory response, and the final elbow extension angle were recorded during ULNT1. ResultsPatients with NNP had significantly decreased pressure pain threshold (P < .001), decreased range of motion of cervical flexion (P < .001), and decreased cervical lateral flexion (P = .001) compared with asymptomatic individuals, whereas no change was identified in range of motion of rotation (P = .100). In ULNT1, 45% of patients with NNP reported pain and 40% of them reported stretch. A total of 65% of asymptomatic individuals reported stretch, and 13% of them reported pain. It was identified in ULNT1 that final elbow extension angle was lower in the NNP group compared with asymptomatic individuals (P = .008). ConclusionMedian nerve mechanosensitivity increased, pressure pain threshold decreased, and active neck motion was limited in individuals with NNP compared with asymptomatic individuals.

Intrarater Agreement of Elbow Extension Range of Motion in the Upper Limb Neurodynamic Test 1 Using a Smartphone Application

ObjectiveTo estimate the intrarater agreement of the Compass application of a smartphone in the assessment of elbow extension range of motion (EE-ROM) at pain onset and maximum tolerable point during the Upper Limb Neurodynamic Test 1 (ULNT1). DesignWithin-day intrarater agreement study. SettingPrivate and university clinical settings. ParticipantsVolunteers (N=41; 21 men; age, 31.34±13.27y; height, 1.67±0.07m; body mass, 70.53±12.37kg) recruited from the community, with no symptoms or musculoskeletal abnormalities in their upper body quadrant and no regional or systemic nerve dysfunction. InterventionsNot applicable. Main Outcome MeasuresNinety-five percent limits of agreement (LOA), standard error of the measurement, and minimal detectable change at the 95% confidence level (MDC95) of EE-ROM at pain onset and maximum tolerable point during the ULNT1. ResultsStandard error of the measurement and MDC95 were relatively high on both sides when considering the onset of pain (standard error of the measurement, 6.6°–6.8°; MDC95, 18.4°–18.8°). Better results were found for the maximum tolerable point (standard error of the measurement, 4.2°–4.8°; MDC95, 11.7°–13.2°). The 95% LOA showed a similar trend. ConclusionsSmartphone measurements showed relatively wide agreement parameters of elbow extension during the ULNT1. These results are, nevertheless, comparable with previous studies using goniometric assessment when considering maximal pain tolerance. Further research is needed before the possible widespread use of the smartphone in neurodynamic assessment.

Upper Limb Neurodynamic Test 1 on Healthy Individuals: Intra- and Intersession Reliability of the Angle between Pain Onset and Submaximal Pain.

Assessment of nerve trunk mechanosensitivity using the upper limb neurodynamic test 1 (ULNT1) often includes measurement of the angle of occurrence in the range of pain onset (PO) and submaximal pain (SP). A measurement that better fits the idea of mechanosensitivity could be the angle between PO and SP (AbOS). This study investigated the intra- and intersession reliability of AbOS, PO, and SP during the ULNT1. Forty-four healthy volunteers underwent three ULNT1 to the point of PO and SP, twice in the first session and once in the second. AbOS, PO, and SP angles of occurrence reliability were examined using the Intraclass Correlation Coefficient (ICC 3,1) and Bland-Altman plots. The intra- and intersession ICC values for AbOS were 0.71 (95% CI: 0.47; 0.85) and 0.79 (95% CI: 0.60; 0.89), respectively. The intra- and intersession mean difference and 95% limits of agreement (±1.96 SD) in the Bland-Altman plots were 2.3° (−18.3°; 23.1°) and 2.8° (−14.7°; 20.4°), respectively. The intra- and intersession reliability of the AbOS during the ULNT1 in healthy individuals is high and higher than the reliability of PO and SP angles of occurrence. The AbOS could be a preferable variable in the assessment of neural mechanosensitivity.

Validity of the Upper Limb Neurodynamic Test 1 for the diagnosis of Carpal Tunnel Syndrome. The role of structural differentiation

BackgroundSeveral studies have analysed the use of the Upper Limb Neurodynamic Test 1 (ULNT1) for diagnosing Carpal Tunnel Syndrome (CTS) obtaining weak diagnostic accuracy, which could be related to the lack of consensus in the selected diagnostic criteria of ULNT1. ObjectiveTo determine the concurrent validity of ULNT1 in comparison to Nerve Conduction Studies (NCS) for the diagnosis of CTS, considering the structural differentiation (SD) as an essential part of the diagnosis. DesignProspective diagnostic test study. MethodsIndividuals with suspected CTS referred for NCS were invited to voluntarily participate in the study. Each participant was tested with NCS and ULNT1. ULNT1 result was considered positive when the patient's clinical symptoms were reproduced during the test and symptoms changed during contralateral neck side bending (SD). Results58 Participants (17 men, 44 women) with suspected CTS and a total of 95 limbs were examined using the NCS and ULNT1. Sensitivity of the ULNT1 was 57.9%, specificity was 84.2%, and the positive and negative likelihood ratios were 3.67 and 0.50 respectively. ConclusionResults obtained in the study may indicate the ability of the ULNT1 to generate small shifts from pre-test to post-test probability. However, imprecision in the CIs limits interpretation from the data. Level of evidence1b.

Mechanosensitivity of the median nerve in patients with chronic carpal tunnel syndrome

The aim was to investigate the relationship between the effects of median nerve strain during the elbow extension component of the upper limb neurodynamic test 1 (ULNT1) and the evoked musculoskeletal changes. 11 patients with chronic carpal tunnel syndrome (CTS) and 11 matched asymptomatic controls participated in the study. In all subjects, elbow extension was carried out in both ULNT1 and neutral positions of the shoulder and arm. From these two starting positions a KIN-COM(®) dynamometer carried out passive elbow extension while EMG activity of 10 arm and shoulder muscles, elbow-flexor resistive torque and elbow extension ROM were measured concurrently. The result showed that, in the ULNT1 position, increased EMG activity of the involved muscles, increased elbow extension resistive torque and pain responses occurred much earlier in the range of elbow extension in the CTS group compared to healthy controls. These findings demonstrated increased mechanosensitivity of the median nerve in CTS patients compared to healthy controls.

Relationship Between Interpretation and Accuracy of the Upper Limb Neurodynamic Test 1 in Carpal Tunnel Syndrome

Objective This prospective diagnostic test study evaluated the relationship between interpretation criteria and accuracy of the Upper Limb Neurodynamic Test 1 (ULNT1) in the diagnosis of carpal tunnel syndrome. Methods A blind comparison with a reference criterion of typical clinical presentation and abnormal median nerve conduction was used. All subjects were first tested with nerve conduction studies and then with ULNT1. Each examiner was blinded to the results collected by the other examiners. Results We analyzed 47 subjects and 84 limbs. Considering ULNT1 as positive in the presence of reproduction of symptoms only in the thumb or lateral 2 fingers, we estimated sensitivity to be equal to 40% (95% confidence interval [CI], 0.256-0.564), specificity 79.59% (95% CI, 0.664-0.885), positive predictive value 58.33% (95% CI, 0.388-0.755), negative predictive value 65% (95% CI, 0.524-0.758), positive likelihood ratio 1.96 (95% CI, 1.275-3.012), and negative likelihood ratio 0.7538 (95% CI, 0.490-1.159). Considering the increase of symptoms with contralateral or decrease of symptoms with ipsilateral cervical side bending as mandatory positivity criterion, specificity improved, but sensitivity decreased. Conclusion Our investigation suggests that the reproduction of symptoms in the thumb or lateral 2 fingers of the affected arm during ULNT1 has weak diagnostic accuracy for carpal tunnel syndrome.

Upper limb neurodynamic test 1 and symptoms reproduction in carpal tunnel syndrome. A validity study

The aim of this study was to estimate the validity of the Upper Limb Neurodynamic Test 1 (ULNT1) for the diagnosis of Carpal Tunnel Syndrome (CTS) with blind comparison to a reference criterion of a compatible clinical presentation and abnormal nerve conduction. 47 subjects with suspected CTS were enrolled. All patients were tested with nerve conduction studies and ULNT1. Considering results as positive in the presence of reproduction of symptoms on affected upper limb, or side-to-side differences in elbow extension, or symptoms modified by lateral neck side-bending, we estimated sensitivity as 91.67%, specificity as 15%, positive likelihood ratio as 1.0784, negative likelihood ratio as 0.5556, and post-test probability for negative test as 40%. Using a new criterion, i.e. the reproduction of symptoms only in the first three digits of the affected hand, we estimated sensitivity as 54.17%, specificity as 70%, positive and negative likelihood ratios as 1.8056 and 0.6548, respectively, and post-test probability for positive test as 68%. Our investigation suggests that the reproduction of the typical current CTS symptoms in the affected hand during ULNT1 testing, improves estimation of the probability of the presence of this condition, even if this test alone cannot be used to diagnose CTS.

Normal response to Upper Limb Neurodynamic Test 1 and 2A

The aim of this study was to establish normal range of motion (ROM) and sensory responses to Upper Limb Neurodynamic Test 1 (ULNT1) and ULNT2A, and to investigate gender and arm dominance influences. ULNT1 and ULNT2A without and with structural differentiation were tested on both arms of 90 healthy participants. At end range the elbow angle was measured for ULNT1and the shoulder abduction angle for ULNT2A. Participants reported where they felt a sensory response and the nature of response. Results showed a wide range of ROM response. Structural differentiation (STD) significantly ( p < 0.01) reduced ROM by 7° (ULNT1) and 10° (ULNT2A). Sensory response was felt more proximally during both tests with STD. There was a statistically significant difference of 2° in ROM during ULNT1 ( p = 0.01) between dominant and non-dominant arm but not during ULNT2A ( p > 0.05). Even though this difference is statistically significant, it may not be clinically significant. In the dominant arm less sensory response was felt and in the non-dominant arm the response was more of neurogenic nature. Gender did not significantly ( p > 0.05) influence ROM or sensory response. These results strengthen the evidence base for clinical practice how to evaluate outcomes from ULNTs.

A study to explore the reliability and precision of intra and inter-rater measures of ULNT1 on an asymptomatic population

Upper Limb Neurodynamic Test 1 (ULNT1) is commonly used within clinical practice. However, the existing evidence regarding its reliability is conflicting and raises methodological questions. Therefore, the aim of this study was to investigate how reliable and precise physiotherapists are at recording both intra and inter-rater measurements of ULNT1 on an asymptomatic population. Forty asymptomatic subjects, 29 females and 11 males (18–42 years, mean 23.35), were recruited into this intra (stability) and inter-rater (equivalence) reliability and precision study. ULNT1 was recorded twice using an electrogoniometer by two experienced physiotherapists using a standardised operational description in conditions replicating clinical practice. Reliability was analysed using the Intraclass Correlation Coefficient (ICC 2,1), and precision using Standard Error of Measurement (SEM) and Smallest Detectable Difference (SDD). The findings demonstrated excellent intra-rater (ICC 2,1 0.98 Rater 1; ICC 2,1 0.96 Rater 2) and good inter-rater (ICC 2,1 0.80) reliability. Precision was acceptable for both intra-rater (SEM 2.59° Rater 1; SEM 0.97° Rater 2; SDD 7.16° Rater 1; SDD 2.68° Rater 2), and inter-rater (SEM 3.83°; SDD 10.58°) measurements. These findings demonstrate that physiotherapists can use ULNT1 reliably and with precision for intra and inter-rater measurements of asymptomatic subjects in conditions that replicate clinical practice. The reproduction of this study on a population of symptomatic subjects is now warranted.

O068 Inertial sensing improves clinical spasticity assessment

To estimate the intrarater agreement of the Compass application of a smartphone in the assessment of elbow extension range of motion (EE-ROM) at pain onset and maximum tolerable point during the Upper Limb Neurodynamic Test 1 (ULNT1).Within-day intrarater agreement study.Private and university clinical settings.Volunteers (N=41; 21 men; age, 31.34±13.27y; height, 1.67±0.07m; body mass, 70.53±12.37kg) recruited from the community, with no symptoms or musculoskeletal abnormalities in their upper body quadrant and no regional or systemic nerve dysfunction.Not applicable.Ninety-five percent limits of agreement (LOA), standard error of the measurement, and minimal detectable change at the 95% confidence level (MDC95) of EE-ROM at pain onset and maximum tolerable point during the ULNT1.Standard error of the measurement and MDC95 were relatively high on both sides when considering the onset of pain (standard error of the measurement, 6.6°–6.8°; MDC95, 18.4°–18.8°). Better results were found for the maximum tolerable point (standard error of the measurement, 4.2°–4.8°; MDC95, 11.7°–13.2°). The 95% LOA showed a similar trend.Smartphone measurements showed relatively wide agreement parameters of elbow extension during the ULNT1. These results are, nevertheless, comparable with previous studies using goniometric assessment when considering maximal pain tolerance. Further research is needed before the possible widespread use of the smartphone in neurodynamic assessment.

Mechanosensitivity of the median nerve and mechanically produced motor responses during Upper Limb Neurodynamic Test 1

Objectives In spite of the widespread use and recognised importance of the Upper Limb Neurodynamic Test 1 (ULNT1) in clinical practice, controversy remains about the neurophysiological basis for sensory and motor responses to the test. The aims of this study were to determine the effects of two limb positions (neutral and ULNT1) on mechanosensitivity of the median nerve, and to investigate the mechanisms underlying muscle stiffness and loss of range during the elbow extension component of the ULNT1. Design In both limb positions, a KIN-COM ® dynamometer controlled passive elbow extension at 3°/second, and recorded both elbow extension range of movement and elbow flexor resistive torque. Setting Electrophysiology laboratory, School of Physiotherapy, University of South Australia. Participants Twenty-six asymptomatic subjects. Main outcome measures Range of elbow extension and elbow flexor resistive torque. Surface electrodes placed over 10 upper limb muscles recorded electromyographic (EMG) activity. Using a hand-held micro-switch, participants indicated occurrence of pain onset and pain that limited further movement. Results The median nerve was more sensitive to mechanical longitudinal stresses during passive elbow extension in the ULNT1 position than in the neutral position, as demonstrated by increased EMG activity and increased mean elbow flexor resistive torque (neutral position, 0.8 Nm, 95% confidence interval 0.7–0.9 Nm; ULNT1 position, 3.9 Nm, 95% confidence interval 3.8–4.0 Nm). Pain onset and pain limit occurred earlier in range in the ULNT1 position (pain onset, 45°, 95% confidence interval 40–50°) than in the neutral position (3°, 95% confidence interval 0–6°). In the ULNT1 position, EMG activity was greater in muscles responsible for an antalgic posture in the upper limb, although some EMG activity was evident prior to pain onset. Conclusions The mechanosensitivity of the median nerve was greater during elbow extension in the ULNT1 position than in the neutral position. The increased EMG activity that occurred primarily in muscles contributing to an antalgic posture with concurrent changes in resistive torque and range of movement may be explained by a flexor withdrawal response to pain that acts to reduce the stretch on the median nerve. Muscle activity prior to pain onset is probably due to mechanoreceptor activation following preferential stretch of the median nerve.