Neck Extensor Muscle Endurance Research Articles

Normative values of neck extensor endurance test in young adults

BackgroundNeck extensor muscles frequently exhibit poor performance in individuals with neck pain. The Deep Neck Extensor Endurance Test (NEET) is commonly used to assess the isometric holding time of the neck extensor muscles. Establishing normative values for this test may assist clinicians in the development of rehabilitation programs. ObjectivesTo identify the average holding time of the NEET in healthy young adults without neck pain. DesignNormative research. Methods440 young adults (172 males and 268 females; age: 18–28 yrs) satisfied eligibility criteria were recruited for participation in this study. The average of hold-time scores for 2 attempts was recorded and used for data analysis. ResultsThe data were not normally distributed; therefore, descriptive data were expressed in terms of median and interquartile range. Demographic data including age, gender, height, weight, Body Mass Index, International Physical Activity Questionnaire expressed as the mean with 95% confidence interval (CI) and range. The average holding time of healthy young adults for NEET was 43.1 (95% CI 38.8 to 46.6), men produced an average hold time of 47.1 (95% CI 46.1 to 51.9) and women produced 40.7 (95% CI 39.9 to 44.0). ConclusionThe holding time of NEET for healthy young adults was 43 seconds. Forty-seven seconds was average hold time for males and for females, it was 40 seconds.

The Effects of Deep Neck Muscle Exercises on Chronic Non-Specific Neck Pain

Introduction: The study aimed to investigate the effects of deep neck flexor (DNF) and deep neck extensor (DNE) muscle exercises on pain, passive range of motion (PROM), craniovertebral angle (CVA), neck flexor endurance (NFE), neck extensor endurance (NEE), and the number of weekly painkiller usage (NWPKU) in chronic non-specific neck pain (CNNP) patients. Materials and Methods: A total of 27 CNNP patients, incuding intervention group (n=15) and control group (n=12), were recruited for this study. Patients in the intervention group participated in 6 weeks of DNF and DNE exercises plus traditional physiotherapy. After 10 sessions (3 weeks), the exercise protocol was followed for 3 weeks of the home-based exercise form. Control group patients received traditional physiotherapy alone. The numeric pain rating scale (NPRS), PROM, CVA, NFE, NEE, and NWPKU were examined and compared between groups, at the baseline and after six weeks. Results: Numeric pain rating scale, PROM, CVA, NFE, NEE, and NWPKU improved significantly in both groups after treatment (P<0.001). The NPRS, passive flexion, passive extension, passive right-side bending, passive left rotation, CVA, NFE, NEE, and NWPKU differences were significant (P<0.05). Conclusion: The study supports the positive effects of combination therapy (DNF and DNE exercises plus traditional physiotherapy) on pain, passive neck range of motion, neck lordosis posture, and neck muscle endurance in CNNP patients.

Effects of exercise therapy using elastic bands on strength and pain in women with non-specific neck pain: A randomised controlled trial

BackgroundCervical pain has a high incidence and worldwide socio-economic effect. Its incidence is lower in men than in women. Conservative and non-pharmacological therapeutic options include strength training. Elastic bands are commonly used in physiotherapy clinics for strength work in patients. Consequently, the objective of this research was to analyse the efficacy of an exercise therapy programme using elastic bands on decreasing pain and increasing strength of the neck flexor musculature, cervical extensor, and scapular stabilizing musculature in women suffering from non-specific cervical pain. MethodsA randomised clinical trial was carried out with 35 subjects with non-specific neck pain (age = 51.7 ± 9.5 and baseline intensity of pain in Visual Analogue Scale = 52.4 ± 9.6). The experimental group (n = 18) performed the exercise programme with elastic bands, consisting of a total of 16 sessions that lasted 45 min. The control group, consisting of 27 participants, reported that they maintained their usual lifestyle throughout the study. The evaluation tools used in this research included the Visual Analogue Scale, Neck Flexor Endurance Test, Neck Extensor Muscle Endurance Test, and Scapular Muscle Endurance Test. ResultsThe experimental group obtained significant improvements in the measurements taken using the Visual Analogue Scale (p < 0.001, d = 4.2), the Neck Flexor Endurance Test (p < 0.001, d = 3.4), the Neck Extensor Endurance Test (p < 0.001, d = 6.3), in the Scapular Muscle Endurance Test (p = 0.016, d = 0.9). ConclusionsThe assessed exercise therapy program utilizing elastic bands demonstrated favorable outcomes in managing non-specific neck discomfort. This intervention resulted in pain reduction and enhanced endurance of the cervical flexor and extensor muscles, along with improved endurance of the scapular stabilizing muscles.Protocol registration in ClinicalTrials.gov: NCT05433649 (registered prospectively, date of registration: June 27, 2022).

Relationships between cervical sagittal posture, muscle endurance, joint position sense, range of motion and level of smartphone addiction

BackgroundFrequent smartphone use in a pathological way forces the user to adopt a compromised posture. This gradually results in changes to both the postural and musculoskeletal systems. This study’s objectives were evaluation of head posture, muscle endurance, neck range of motion (ROM) and joint position sense in two separate smartphone user groups, one ‘Addicted’, the other ‘Non-Addicted’.MethodsA sample of convenience (n = 60) was recruited from medical students (age 24.57 ± 4.38, 53.3% male) with a history of smartphones use > 2 h/day for 1-year. Based on the cut-off values of the smartphone addiction scale-short version (SAS-SV), participants were entered into each group (cut-off for male ≥ 31, female ≥ 33). Neck muscle endurance time, joint position error and cervical ROM, along with forward head posture parameters of craniovertebral angle (CVA), shoulder angle (SA), sagittal head angle (SHA) and forward head distance (FHD)) were evaluated. A Mann–Whitney test and Spearman correlation coefficient were used to determine the difference between groups and the correlations between variables.ResultsThe difference between ‘Addicted’ and ‘Non-Addicted’ groups was confirmed by the values for SAS-SV scores (25.23 ± 5.5 versus 43.9 ± 6.61) (p < 0.001). There were statistically significant differences between groups for the CVA and FHD parameters (p < 0.001). Further, the neck extensor muscle endurance (97 ± 3.79 versus 74.86 ± 2.23 s), was significantly different between groups (p = 0.010) but not after Bonferroni correction. There was no notable difference in the neck flexor muscle endurance, joint position error, SA, and SHA parameters between groups (p > 0.05).ConclusionsThere is a positive correlation between smartphone addiction and both decreased extensor muscle endurance and changes in neck postural alignment.

Evaluation of dynamic spinal alignment changes and compensation using three-dimensional gait motion analysis for dropped head syndrome

BACKGROUND CONTEXTDynamic kinematic evaluation of spino-pelvic alignment during gait using three-dimensional (3D) motion analysis has been proposed for adult spinal thoracolumbar deformity. That is because conventional full-spine radiographs cannot be used to evaluate dynamic factors. However, dynamic changes in spino-pelvic alignment during gait for dropped head syndrome (DHS) have not been studied using this approach. PURPOSE: This study aimed to assess the dynamic changes in spinal-pelvic alignment during gait in patients with DHS using 3D motion analysis. STUDY DESIGNRetrospective review of collected radiographic and kinematic data. PATIENT SAMPLENineteen DHS patients with neck pain and/or anterior gaze disturbance. OUTCOME MEASURESStatic spino-pelvic radiological alignment, dynamic spino-pelvic kinematic parameters and electromyogram (EMG) data. METHODSCenter of gravity of the head - C7 sagittal vertical axis (CGH-C7 SVA), C2-C7 SVA, T1 slope; cervical lordosis (CL), C7SVA, thoracic kyphosis (TK), lumbar lordosis (LL), pelvic tilt (PT) and pelvic incidence (PI) were assessed using full-spine radiographs in a standing position to assess static spino-pelvic alignment. The 3D gait motion analysis was conducted during gait. Dynamic kinematic parameters were divided into spinal segments: cervical (C-), thoracic (T-), lumbar (L-) and pelvis (P-). Each spinal segment coronal angle to the pelvic angle, each spinal segment sagittal angle to the pelvic angle and pelvic sagittal angle to the horizontal axis were assessed as dynamic spino-pelvic kinematic parameters. Trunk and lower limb muscle activity during gait were assessed using wireless surface EMG analysis. Dynamic spino-pelvic kinematic variables and muscle activity were compared between the first walking lap and the final lap during gait analysis. The change in dynamic kinematic parameters was correlated with static radiological alignment and electromyographic muscular activity change. RESULTSCervical and thoracic anterior tilt increased significantly after an extended period of walking, indicating that dropped head worsened during gait. An increase of cervical anterior tilt during walking was significantly associated with decreased muscle activity in the cervical paraspinal muscles (r=-0.463, P<.05) and latissimus dorsi (r=-0.763, p<.01). Furthermore, significant correlations were found between a change in thoracic sagittal angle to pelvic angle and C7SVA (r=0.683, p<.01) and LL (r=-0.475, p<.05). This means that a larger C7SVA and smaller LL were associated with increased thoracic anterior tilt during gait. CONCLUSIONSThe 3D motion analysis for DHS showed that cervical and thoracic anterior tilt significantly increased after extended walking, resulting in worsening of dropped head. Decreased muscle activity of the neck extensor muscles during gait suggests insufficient neck extensor muscle endurance, which was associated with increased cervical anterior tilt. A greater increase in the thoracic anterior tilt during gait was found in DHS patients with a larger C7SVA and smaller LL due to insufficient thoracolumbar compensation for the dropped head. Correction of the cervical spine alone would not be sufficient to improve dropped head in cases with increased thoracic anterior tilt during gait. The results suggest that C7SVA and LL are crucial parameters in the surgical strategy for DHS.

Acute Pain, Neck Extensor Endurance, and Kinematic Changes Resulting from Sustained Neck Flexion during Smartphone Use

OCCUPATIONAL APPLICATIONS The National Occupational Research Agenda for Musculoskeletal Health in the United States identified that with the changing nature of the traditional office environment, mobile devices are now frequently used for longer durations, warranting research on the impacts of mobile computing on musculoskeletal health. A recent study of office workers showed that those with “smartphone overuse” were six times more likely to report neck pain. Working in pain may also result in withdrawal and less proactive extra-role behaviors at work (such as making recommendations at work and willing to help colleagues). We found that 30-minutes of mobile device use resulted in pain reporting in the neck and upper back when the device was used with neck flexion. This musculoskeletal pain could lead to acute concerns during the workday and long-term problems over time.

Effect of Smartphone Usage on Neck Muscle Endurance, Hand Grip and Pinch Strength among Healthy College Students: A Cross-Sectional Study.

In recent years, there has been a significant increase in global smartphone usage driven by different purposes. This study aimed to explore the effect of smartphone usage on neck muscle (flexors and extensors) endurance, hand grip, and pinch strength among young, healthy college students. In total, 40 male students were recruited for this study; 20 of them belonged to the smartphone-addicted group, while the other 20 were in the non-addicted group based on their smartphone addiction scale—short version (SAS-SV) scores (the threshold for determining smartphone addiction: 31/60). Neck flexor endurance time, the ability to perform a neck extensor muscle endurance test, and hand and pinch grip strength were assessed. Multivariate analysis of variance (MANOVA) was used to assess between-group differences in the mean values of neck flexor endurance time, hand grip, and pinch grip. A significant group effect (Wilks’ lambda = 0.51, F (5,34) = 6.34, p = 0.001, partial eta squared = 0.48) was found. A decrease in neck flexor endurance time was observed in the smartphone-addicted group compared with that of the non-addicted group (p < 0.001). However, there was no notable difference in the neck extensor muscle endurance test or in hand grip and pinch grip strength of both hands between groups (p > 0.05). Using a smartphone for a prolonged time might affect neck flexor muscle endurance; however, more research is needed to explore the long-term effects of using smartphones on neck muscle endurance and hand/pinch grip strength and the risk of developing upper limb neuromusculoskeletal dysfunction.

Comparison and Association of Neck Extensor Muscles’ Endurance and Postural Function in Subjects with and without Chronic Neck Pain – A Cross-Sectional Study

Abstract Purpose Neck extensor endurance (NEE) and position sense are vital for maintaining cervical spine function and defects in these processes may be associated with impaired postural control in chronic neck pain (CNP) subjects. The study’s objectives are 1) to compare the cervical extensor endurance capability and postural control of CNP subjects with those of asymptomatic controls; 2) to investigate the association between NEE and postural control. Materials and Methods Sixty-four participants (38 asymptomatic, 38 with CNP) participated in this cross-sectional study. NEE was assessed using a clinical extensor endurance test. Under open and closed eyes conditions, postural control measures were tested with the Good Balance system. The postural control parameters were AP-velocity (mm/s), ML-velocity (mm/s) and Velocity moment (mm2). NEE capacity and postural control parameters were compared and correlated between asymptomatic and CNP subjects. Results and Discussion CNP subjects showed lower NEE capacity (p&lt;0.001) and significantly larger AP-velocity (p&lt;0.001), ML-velocity (p&lt;0.001) and Velocity moment (p&lt;0.001) than asymptomatic participants. NEE negatively correlated with AP-velocity (r=−0.51, p=0.001), ML-velocity (r=0.46, p=0.003) and velocity moment (r=0.38, p=0.020) in asymptomatic subjects in eyes open condition and no correlations in subjects with CNP. CNP subjects showed increased postural sway velocities and lowered extensor endurance capacity compared to asymptomatic participants. No correlations existed between NEE and postural control parameters in CNP subjects.

Comparison of neck extensor muscle endurance and cervical proprioception between asymptomatic individuals and patients with chronic neck pain

IntroductionNeck extensor endurance (NEE) and cervical proprioception are vital for maintaining cervical spine function and defects in these processes have been associated with chronic neck pain (CNP). The objectives of the study are 1) To investigate the association between NEE and cervical joint position error (JPE) in subjects with CNP; 2) to compare the cervical extensor endurance and cervical JPE of CNP subjects with those of asymptomatic controls; and 3) to determine the relationship between Pain Catastrophizing Scale (PCS) scores, NEE, and cervical JPE in subjects with CNP. MethodSixty-four participants (32 asymptomatic, 32 with CNP) participated in this comparative cross-sectional study. Cervical proprioception was assessed by measuring the absolute JPE in the sagittal and transverse directions. NEE was assessed using a clinical extensor endurance test. NEE capacity and JPE were compared and correlated between asymptomatic and CNP subjects. Pain catastrophic behavior was assessed using the Pain Catastrophizing Scale (PCS) in CNP subjects. ResultsCNP subjects showed lower NEE capacity (p < 0.001) and significantly larger JPEs (p < 0.001) than asymptomatic participants. NEE negatively correlated with JPEs in all directions (p < 0.001) in asymptomatic subjects and only neck extension errors showed a correlation in CNP subjects (r = −0.45, p = 0.009). PCS scores were negatively correlated with endurance capacity (r = −0.42, p = 0.017) and positively correlated with JPE (flexion: r = 0.57, p = 0.001). ConclusionCNP subjects showed impaired proprioception and lower endurance capacity compared to asymptomatic participants. Neck extension errors alone correlated with JPE in CNP subjects. PCS scores negatively correlated with NEE in subjects with CNP.

Intra and Inter-Rater Reliability for Deep Neck Flexor and Neck Extensor Muscle Endurance Tests in Subjects with and without Subclinical Neck Pain

Abstract Purpose Deep neck flexor (DNF) and neck extensor (NE) muscle endurance tests are a part of standard assessment procedure in routine physical therapy practice and these tests needs to be reliable. Materials and Methods Intra-rater (between-day) and inter-rater (within-day) reliability was assessed for 2 neck muscle endurance tests in 26 subclinical neck pain and 31 normal subjects by 2 blinded assessors. The tests conducted included 1) DNF endurance test performed in supine and 2) NE muscle endurance test performed in prone position. Results and discussion The Intra-rater and inter-rater reliability was determined by means of Intra Class Correlation (ICC), with 95% confidence intervals. The intra rater reliability testing showed good agreement for both DNF (ICC=0.76 and 0.78) and NE muscle endurance (ICC=0.75 and 0.76) tests. Meanwhile, the inter-rater reliability showed moderate to good agreement for both DNF (ICC – 0.58 and 0.61) and NE muscle endurance tests (ICC – 0.57 and 0.74) in subjects with subclinical neck pain. Subclinical neck pain subjects had a significantly lower endurance holding times compared to normal (p&lt;0.001). Conclusion The intra and inter rater reliability ranged from moderate to good agreement. Neck flexor and extensor muscle endurance can be measured reliably in a clinical setup in subjects with subclinical neck pain.

The Effect of Ergonomic Latex Pillow on Head and Neck Posture and Muscle Endurance in Patients With Cervical Spondylosis: A Randomized Controlled Trial

ObjectivesCervical pillows have frequently been reported to attenuate the symptoms of pain and disability. Although the main role of pillows is to optimize head and neck posture and relax the neck muscles, limited studies have examined the effectiveness of pillows from aspects beyond subjective outcome measures, especially their effect on head and neck posture and muscle performance. This study examines the effect of ergonomic latex pillow on the craniovertebral (CV) angle and cervical flexor and extensor muscle endurance in patients with cervical spondylosis. MethodsThis parallel-group, randomized, controlled trial was conducted from January to June 2017. The patients with cervical spondylosis were randomly allocated to the experimental and control groups, who both received identical standard physiotherapy 3 × a week for 4 weeks. The experimental group received an ergonomic latex pillow, but the control group was asked to continue sleeping on their usual pillow. The CV angle and flexor and extensor muscle endurance were measured before and after the intervention. The independent-sample t test was used to compare changes in the CV angle, whereas the Mann-Whitney test was used to compare changes in flexor and extensor muscle endurance between the groups, respectively. ResultsThe experimental group showed significant changes in the CV angle and extensor muscle endurance. A significant increase was observed in extensor muscle endurance in the experimental group compared with the control group. ConclusionThe ergonomic latex pillow may affect neck extensor muscle endurance and CV angle in patients with cervical spondylosis, although further studies are needed before any recommendations.

Pain neuroscience education plus exercise compared with exercise in university students with chronic idiopathic neck pain

Background/Aims Neck pain is a common complaint. Its prevalence is particularly high in university students. This study examined the effects of pain neuroscience education plus exercise when compared with exercise only in university students with chronic idiopathic neck pain. Methods University students with chronic neck pain were randomly allocated to receive pain neuroscience education plus exercise, or exercise only intervention, and assessed at baseline, after the intervention and at 3-month follow-up. Pain intensity (primary outcome), disability, fear of movement, catastrophising, knowledge of pain neurophysiology, pressure pain thresholds and neck and scapular muscle endurance were measured to determine the impact of the interventions. Results It was found that disability (F=17.3, P&lt;0.001; partial eta2=0.48), fear of movement (F=5.3, P=0.009; partial eta2=0.22), catastrophising (F=16.4, P&lt;0.001; partial eta2=0.48) and neck extensor endurance (F=11.0, P=0.002; partial eta2=0.19) changed significantly over time. There was a significant increase in neurophysiology of pain questionnaire score for the group receiving pain neuroscience education plus exercise but not for the group receiving exercise only (group vs time interaction: F=19.8, P&lt;0.001; partial eta2=0.51). No other significant differences were found. Conclusions Pain neuroscience education plus exercise has comparable results to exercise only, with the exception of knowledge about pain neurophysiology. The impact of this difference needs to be explored in future studies.

Comparing neck extensor muscle function in asymptomatic Canadian adults and adults with tension-type headache: a cross-sectional study

AimTo further the understanding of the pathophysiological mechanisms underlying tension-type headache (TTH) by comparing the endurance and strength of neck extensor muscles under acute muscle fatigue in participants with TTH...

Effect of jaw functional status on neck muscle endurance

ObjectiveTo investigate the effect of resting jaw and maximum voluntary clenching on neck flexor and extensor muscle endurance. DesignNeck flexor and extensor endurance was measured in a college health clinic in 85 male college students in two test positions: resting jaw (control) and maximum voluntary clenching. ResultsMean neck flexor muscle endurance values during resting jaw and maximum voluntary clenching were 70.06 SD 28.24, and 60.03 SD 16.5, seconds respectively. Mean neck extensor muscle endurance values during resting jaw and maximum voluntary clenching were 105.54 SD 29.9, and 98.32 SD 24.54, respectively. Both values were significantly lower while maximum voluntary clenching as compared to resting jaw position (p < 0.05). ConclusionModification of jaw position can affect neck muscle endurance. Results of this study further supports sensory-motor relation between jaw and neck region.

Neck Flexor and Extensor Muscle Endurance in Subclinical Neck Pain: Intrarater Reliability, Standard Error of Measurement, Minimal Detectable Change, and Comparison With Asymptomatic Participants in a University Student Population

ObjectiveThe aims of this study were to assess intrarater reliability and to calculate the standard error of measurement (SEM) and minimal detectable change (MDC) for deep neck flexor and neck extensor muscle endurance tests, and compare the results between individuals with and without subclinical neck pain. MethodsParticipants were students of the University of Aveiro reporting subclinical neck pain and asymptomatic participants matched for sex and age to the neck pain group. Data on endurance capacity of the deep neck flexors and neck extensors were collected by a blinded assessor using the deep neck flexor endurance test and the extensor endurance test, respectively. Intraclass correlation coefficients (ICCs), SEM, and MDC were calculated for measurements taken within a session by the same assessor. Differences between groups for endurance capacity were investigated using a Mann-Whitney U test. ResultsThe deep neck flexor endurance test (ICC = 0.71; SEM = 6.91 seconds; MDC = 19.15 seconds) and neck extensor endurance test (ICC = 0.73; SEM = 9.84 minutes; MDC = 2.34 minutes) are reliable. No significant differences were found between participants with and without neck pain for both tests of muscle endurance (P > .05). ConclusionThe endurance capacity of the deep neck flexors and neck extensors can be reliably measured in participants with subclinical neck pain. However, the wide SEM and MDC might limit the sensitivity of these tests.

Neck muscle endurance and head posture: A comparison between adolescents with and without neck pain

ObjectiveThe main aims of this study were to compare the neck flexor and extensor endurance and forward head posture between adolescents with and without neck pain. The secondary aims were to explore potential associations between muscles endurance, head posture and neck pain characteristics and to assess intra-rater reliability of the measurements used. MethodsAdolescents with neck pain (n = 35) and age-matched asymptomatic adolescents (n = 35) had their forward head posture, neck flexor endurance and neck extensor endurance measured using clinical tests. Intra-rater reliability was also assessed. ResultsForward head posture and neck flexor and extensor endurance tests showed moderate to almost perfect intra-rater reliability (ICC between 0.58 and 0.88). Adolescents with neck pain showed significantly less forward head posture (neck pain = 46.62 ± 4.92; asymptomatic = 44.18°± 3.64°, p > 0.05) and less neck flexor (neck pain = 24.50 ± 23.03s; asymptomatic = 35.89 ± 21.53s, p > 0.05) and extensor endurance (neck pain = 12.6.64 ± 77.94s; asymptomatic = 168.66 ± 74.77s, p > 0.05) than asymptomatic adolescents. ConclusionsResults suggest that changes in posture and neck muscle endurance are a feature of adolescents with neck pain.

Isometric Endurance of Neck Muscles and Muscles for Scapular Positioning in Individuals With and Without Postural Neck Pain

Postural neck pain results from poor posture, arising through the sustained, long term, abnormal physiological loads imposed on the neck with a consequent reduction in neck and scapular muscle strength. The purpose of this study was to compare isometric muscle endurance in the neck and scapulothoracic region in individuals with and without postural neck pain. Methodology: Twenty-five patients between 20 to 50 years old with postural neck pain were chosen from the out-patient departments of Srinivas College of Physiotherapy and Rehabilitation Centre and Government Wenlock Hospital, Mangalore, and 25 healthy age matched individuals from society. The Neck Disability Index (NDI) for patients, isometric Neck Flexor Endurance (NFE), Scapular Muscle Endurance (SME), Neck Extensor Endurance (NEE), and pain using a visual analogue scale (VAS) for subjects in both groups were measured. Results: Highly significant differences in NFE (t = -7.704 and p &lt; 0.001) and SME (t = 6.147 and p = 0.05) while no significant difference in NEE (t = -13.027 and p &gt; 0.05) were found between symptomatic and asymptomatic groups. Furthermore, correlations were found between NFE and VAS (r = 0.521), NEE and NDI (r = -0.709), and NEE and VAS (r = -0.411) while no correlation (p &gt; 0.05) was found between SME and VAS (r = 0.051), NFE and NDI (r = 0.163), and SME and NDI (r = -0.110). Conclusion: It is concluded that there is a significant decrease in isometric endurance of neck muscles and muscles for scapular positioning in neck pain patients. Pain and disability are the significantly affecting factors of isometric endurance of neck muscles and muscles for scapular positioning in postural neck pain patients.

Patients With Temporomandibular Disorders Have Increased Fatigability of the Cervical Extensor Muscles

To determine whether patients with myogenous and mixed temporomandibular disorders (TMD) have greater fatigability of the cervical extensor muscles while performing a neck extensor muscle endurance test (NEMET) when compared with healthy controls. A total of 151 individuals participated in this study. Of these 47 were healthy controls, 57 patients had myogenous TMD, and 47 patients had mixed TMD. All patients performed the NEMET. The patients were instructed to maintain a prone lying position with the neck unsupported as long as possible, stopping at signs of fatigue or any discomfort. Electromyographic activity of the cervical extensor muscles during the NEMET and the holding time were collected for all patients and were compared across groups. A 1-way analysis of variance was used to evaluate the differences in holding time between patients with TMD and healthy controls. A mixed model analysis was used to evaluate the differences in normalized median frequency at different times (fatigue index) for the cervical extensor muscles while performing the NEMET between patients with TMD and controls. There were statistically significant differences (P<0.05) in the slopes of the normalized median frequency between patients with TMD and healthy controls at 10, 30, 40, 50, 60, 70, 80, 90, and 100 seconds of the NEMET. Holding time was significantly reduced in both patients with myogenous TMD and mixed TMD when compared with healthy controls (P<0.05). These results highlight the fact that alterations of endurance capacity of the extensor cervical muscles could be implicated in the neck-shoulder disturbances presented in patients with TMD.

Maximal muscle strength and EMG activity of the shoulder/neck muscles in females with work-related neck muscle pain

Neck extensor endurance (NEE) and cervical proprioception are vital for maintaining cervical spine function and defects in these processes have been associated with chronic neck pain (CNP). The objectives of the study are 1) To investigate the association between NEE and cervical joint position error (JPE) in subjects with CNP; 2) to compare the cervical extensor endurance and cervical JPE of CNP subjects with those of asymptomatic controls; and 3) to determine the relationship between Pain Catastrophizing Scale (PCS) scores, NEE, and cervical JPE in subjects with CNP.Sixty-four participants (32 asymptomatic, 32 with CNP) participated in this comparative cross-sectional study. Cervical proprioception was assessed by measuring the absolute JPE in the sagittal and transverse directions. NEE was assessed using a clinical extensor endurance test. NEE capacity and JPE were compared and correlated between asymptomatic and CNP subjects. Pain catastrophic behavior was assessed using the Pain Catastrophizing Scale (PCS) in CNP subjects.CNP subjects showed lower NEE capacity (p < 0.001) and significantly larger JPEs (p < 0.001) than asymptomatic participants. NEE negatively correlated with JPEs in all directions (p < 0.001) in asymptomatic subjects and only neck extension errors showed a correlation in CNP subjects (r = −0.45, p = 0.009). PCS scores were negatively correlated with endurance capacity (r = −0.42, p = 0.017) and positively correlated with JPE (flexion: r = 0.57, p = 0.001).CNP subjects showed impaired proprioception and lower endurance capacity compared to asymptomatic participants. Neck extension errors alone correlated with JPE in CNP subjects. PCS scores negatively correlated with NEE in subjects with CNP.