Trapezius Muscle Stiffness Research Articles

The effect of a 5-week therapeutic massage on erector spinae and upper trapezius muscle stiffness as determined by shear-wave elastography: a randomized controlled trial.

Massage is an effective treatment for reducing pain, swelling, stiffness, and improving muscle mobility. Although self-reported benefits on muscle stiffness and pain are well-known, studies measuring muscle stiffness objectively are scarce. A randomized controlled trial involving 30 recreationally active young women (22.3 ± 0.4 years) was conducted. The participants were randomly assigned to either the control group or the intervention group which received a series of five 30-min whole back therapeutic massage sessions over 5 weeks. Shear wave elastography was used to assess muscle stiffness (erector spinae (ESp) and upper trapezius (UT) muscles) before and after the intervention and at 3-week follow-up. For ESp, there was no statistically significant time × group interaction (F = 2.908; p = 0.063). However, there was a statistically significant and large time × group interaction for UT (F = 13.533; p = 0.006; η 2 = 0.19). Post-hoc testing for time indicated that the shear modulus in the intervention group was reduced at follow-up (p = 0.005; d = 1.02), while the difference between baseline and post-intervention measurements were not statistically significant (p = 0.053; d = 0.75). In conclusion, massage significantly reduced proximal UT stiffness both 3 days and 3 weeks after the intervention. However, it had no significant effect on the distal part of UT or the ESp muscle.

Ultrasound imaging and guidance in the management of myofascial pain syndrome: a narrative review.

Myofascial pain syndrome (MPS) is a common musculoskeletal disorder characterized by muscle pain, tenderness, and trigger points. Ultrasonography has emerged as a key tool for diagnosing and treating MPS owing to its ability to provide precise, minimally invasive guidance. This review discusses the use of ultrasonography in various approaches to evaluate and manage MPS. Studies have shown that shear-wave sonoelastography can effectively assess muscle elasticity and offer insights into trapezius stiffness in patients with MPS. Ultrasound-guided interfascial hydrodissection, especially with visual feedback, has demonstrated effectiveness in treating trapezius MPS. Similarly, ultrasound-guided rhomboid interfascial plane blocks and perimysium dissection for posterior shoulder MPS have significantly reduced pain and improved quality of life. The combination of extracorporeal shockwave therapy with ultrasound-guided lidocaine injections has been particularly successful in reducing pain and stiffness in trapezius MPS. Research regarding various guided injections, including dry needling, interfascial plane blocks, and fascial hydrodissection, emphasizes the importance of ultrasonography for accuracy and safety. Additionally, ultrasound-guided delivery of local anesthetics and steroids to the quadratus lumborum muscle has shown lasting pain relief over a 6-month period. Overall, these findings highlight the pivotal role of ultrasonography in the assessment and treatment of MPS.

Scapular muscle dynamic stiffness of asymptomatic subjects and subjects with chronic shoulder pain, at rest and isometric contraction conditions.

Muscle stiffness had a crucial role in joint stability, particularly, at the shoulder complex. Although changes in upper trapezius muscle stiffness have been described for shoulder pain, contradictory findings have been obtained. Also, existing data regarding scapular muscles are, majorly, about trapezius. Myotonometry is a method used to assess stiffness; however, the reliability values of scapular muscle stiffness through this method have not been assessed in shoulder pain conditions. The present study aims to compare scapular muscles' stiffness (trapezius, serratus anterior, and levator scapulae) between subjects with and without chronic shoulder pain and to evaluate the related test-retest reliability. Twenty-two symptomatic and twenty-two asymptomatic subjects participated in a cross-sectional study. The dynamic muscular stiffness of scapular muscles, at rest and during an isometric contraction, was measured bilaterally with myotonometry, in two moments. The differences in bilateral averaged values between symptomatic and asymptomatic subjects and the effect of the group (group presenting pain in the dominant or non-dominant side, and asymptomatic group) and of the limb (unilateral painful or asymptomatic limb, and bilateral asymptomatic limbs) were investigated. Test-retest intra-rater reliability was determined. An effect of the group was observed at rest, for middle trapezius stiffness, and during contraction, for middle and lower trapezius stiffness. For middle trapezius, increased values were observed in the group presenting pain in non-dominant side comparing to both groups or to group presenting pain in dominant side. The intraclass correlation coefficient, majorly, ranged between 0.775 and 0.989. Participants with pain in the non-dominant side presented an increased middle trapezius' stiffness. Globally, high reliability was observed for scapular muscles dynamic stiffness.

Assessment of the stiffness of the upper trapezius muscle in a group of asymptomatic people with cervical spine rotation asymmetry.

This study investigated the relationship between the stiffness of the upper trapezius muscle and the range of rotational movement of the cervical spine. A total of 60 right-handed asymptomatic students participated in the study. Participants (N = 22) characterised by asymmetry in rotational movements were selected for the experimental group. A difference of ≥10° between right and left rotation of the cervical spine was considered asymmetrical. The control group (N = 38) included participants whose rotation difference was < 10°. Belonging to the experimental or control group did not significantly differentiate trapezius muscle stiffness. The rotation side differentiated the stiffness of the right and left trapezius muscles only in the group of people with rotational movement asymmetry. There were high correlation coefficients between right cervical rotation and the stiffness of the muscle on the right side, and between rotation to the left and the stiffness of the muscle on the left side. There is a relationship between the stiffness of the right and left upper trapezius muscles and the range of right and left rotational motion of the cervical spine. Stiffness of the upper trapezius correlates more strongly with rotation to the side on which the muscle lies than to the opposite side. Increased stiffness of the upper trapezius muscle on the side of limited cervical spine rotation is likely to be determined by the muscle fibre stretching mechanism.

Differential Effects of Classical vs. Sports Massage on Erector Spinae and Upper Trapezius Muscle Stiffness: A Shear-Wave Elastography Study in Young Women.

Classical and sports massages are commonly used interventions, but their comparative effects on muscle stiffness remain unclear. Classical massage is more general and uses light to moderate pressure, and its main purpose is relaxation. Sports massage, on the other hand, is more specialized and targets the unique needs of massaged individuals using moderate to firm pressure. This study aimed to evaluate the impacts of classical and sports massages on the stiffness of the erector spinae (ES) and upper trapezius (UT) muscles. Fifteen recreationally active young women, aged 22.9 ± 1.2 years, underwent a randomized cross-over study (with three conditions). Participants received either a five-minute classical or sports massage or a passive rest as a control on distinct days. Muscle stiffness was assessed using shear-wave elastography. The ES shear modulus displayed a significant time effect (p < 0.001; η2 = 0.515) without noticeable differences between the conditions, and the time × massage-type interactions approached statistical significance (F = 2.014; p = 0.073). There was also a large and statistically significant effect of the time on the UT (F = 11.127; p < 0.001; η2 = 0.443). We could not prove that classical and sports massages reduced muscle stiffness. The absence of significant differences might be attributed to the specific intervention parameters (massage duration of 5 min) and the small, only young women sample size. Given some tendencies towards significant effects, larger sample sizes are needed to further investigate this research question.

Akıllı Telefon Bağımlılığına Bağlı Boyun Ağrısında Kı̇nesyolojik Bandın Ağrı ve Trapez Kasının Mekanı̇k Özellı̇klerı̇ Üzerı̇ne Akut Etkı̇sı̇

This study aimed to assess the short-term effects of inhibitory kinesiologic tape (KT) and sham tape on neck pain and muscle tone in individuals with smartphone addiction. Forty-two healthy participants were randomized to receive either KT or sham tape application to their upper trapezius muscle (UTM). Smartphone addiction was assessed using the Smartphone Addiction Scale (SAS), and pain severity was measured using the Visual Analogue Scale (VAS). Muscle tone and stiffness were evaluated using a myotonometer. No significant differences were found in pain or muscle mechanical properties between the groups after treatment. However, KT recipients had significantly higher tone and stiffness in their left trapezius muscle compared to their right trapezius muscle (p &lt; 0.05). Additionally, right trapezius stiffness was significantly higher in participants with SAS scores of 100 points or more compared to those with SAS scores below 100 points (p &lt; 0.05). Finally, left trapezius elasticity increased significantly in participants with SAS scores of 100 points or more (p &lt; 0.05). Overall, the study findings suggest that short-term application of KT to the UTM may reduce neck pain in individuals with smartphone addiction.

Which muscles exhibit increased stiffness in people with chronic neck pain? A systematic review with meta-analysis.

Chronic neck pain (CNP) substantially impacts quality of life, posing both personal challenges and economic strains. This systematic review sought to discern muscle-specific stiffness differences between CNP patients and individuals without CNP. We searched the PubMed, Scopus, and PEDro databases for studies using ultrasound elastography or myotonometry to compare muscle stiffness between CNP patients and asymptomatic controls. Using a meta-analysis with a random-effects model, we derived the pooled effect as standardized mean difference (SMD). Out of the six studies selected, the adjusted Newcastle-Ottawa rating scale for cross-sectional studies denoted three as moderate-quality and three as high-quality. Our findings indicate that the upper trapezius (UT) stiffness was elevated in CNP patients compared to their counterparts without CNP (SMD = 0.39, 95% CI = 0.05 to 0.74; p = 0.03; small effect size). The data for other muscles remained inconclusive. Given the case-control design of all reviewed studies, a direct causative link between UT stiffness and CNP is yet to be confirmed. As such, recommending a reduction in trapezius muscle stiffness as a primary rehabilitation strategy for CNP patients is still inconclusive and further research is needed.

Stiffness and thickness of the upper trapezius muscle increase after repeated climbing bouts in male climbers.

Indoor climbing involves overloading the shoulder girdle, including the rotator cuff and upper trapezius muscles. This on the field study aimed to investigate the effects of repeated climbing bouts on morphological and mechanical measures of the upper trapezius muscle. Fifteen experienced male climbers participated in the study. Rate of perceived exertion (RPE), blood lactate concentration ([La-]b), and stiffness and thickness over four points of the upper trapezius were assessed before and after a repeated climbing exercise. The procedure for the climbing exercise consisted of five climbs for a total time of 5-minutes per climb, followed by a 5-minute rest. The analysis showed an increase from baseline to after the 3rd climb (p≤0.01) for RPE and after the 5th climb for [La-]b (p≤0.001). Muscle stiffness and thickness increased at all points (1-2-3-4) after the 5th climb (p≤0.01). We found spatial heterogeneity in muscle stiffness and thickness; muscle stiffness was the highest at Point 4 (p≤0.01), while muscle thickness reached the highest values at points 1-2 (both p≤0.01). Moreover, the analysis between the dominant and non-dominant shoulder showed greater stiffness after the 1st climb at Point 1 (p=0.004) and after the 5th climb at Point 4 (p≤0.001). For muscle thickness, the analysis showed significant changes in time and location between the dominant and the non-dominant shoulder. Bilateral increases in upper trapezius muscle stiffness and thickness, with simultaneous increases in RPE and blood lactate in response to consecutive climbs eliciting fatigue.

Effect of Myofascial Induction Therapy in Pterygoid Muscles of Woodwinds and String Musicians on Muscular Stiffness of the Upper Trapezius.

Considering the fascial continuity and its biomechanical characteristics, the purpose of this study was to assess the change in muscular stiffness (Dm) of the upper trapezius muscles after the application of myofascial induction therapy (MIT) to the masticatory muscles of musicians. This was a pre-posttest design involving one treatment. The total sample was 33 subjects (n = 33). The experimental group comprised 18 violin, viola, and woodwind players, and the control group was comprised of 15 non-musicians. The outcome measures included pre-posttest measurements with tensiomyography of the upper trapezius (muscle stiffness, Dm), and baseline neck disability (Neck Disability Index), and pain (SF-36 questionnaire). The experimental group received MIT for 5 minutes on each side of the lateral pterygoid muscle. The control group assumed a supine position for 10 minutes. After the intervention, there was a significant difference in Time per Group (F = 2.896, p = 0.034, ƞ2p = 0.367, and w = 0.755). There were statistically significant differences in pre-post and side-by-side analyses for the Dm of the upper trapezius in the experimental group as well as between the two groups. MIT of the lateral pterygoids is effective in decreasing upper trapezius stiffness as measured by an increase in the Dm measured by tensiomyography. The greatest change occurred in musicians with a lower percentage of Neck Disability Index at baseline.

Lack of Objective Measurement in the Initial Screening and Follow-Up of Patients Who Report Whiplash Injury—Is Elastography of the Trapezius Muscle an Answer?

Background: Painfully decreased cervical range of motion accompanied by muscle spasm is a common presentation of whiplash injury of the neck. Stiffness of the cervical muscles can be assessed by ultrasound shear wave elastography (SWE), expressed in kilopascals (kPa). The hypothesis: SWE of the trapezius muscle is an objective measurement suitable for the initial screening and follow-up of patients who report whiplash injury. Methods and results: A total of 99 patients after whiplash injury were compared to 75 control participants. Mean trapezius stiffness was 82.24 ± 21.11 vs. 57.47 ± 13.82 for whiplash patients and controls, respectively. The cut-off value of SWE of 75.8 kPa showed 77% accuracy in correctly assigning patients to the whiplash or control group. To evaluate whether SWE can be used as a follow-up method of recovery after a whiplash injury, initial and endpoint SWE (after six months, n = 24) was carried out. Patients reporting no recovery showed similar SWE values as completely recovered patients. This finding refutes the second part of our hypothesis. Conclusions: SWE is a method that can be used for the initial screening of patients with whiplash injury, but we are still searching for an objective measurement that can be used in the follow-up of recovery.

Neck Disability Index Is Better in Classification of Recovery after Whiplash Injury in Comparison with Ultrasound Shear Wave Elastography of Trapezius Muscle.

A prospective observational study comparing shear wave elastography (SWE) of trapezius muscle with Neck Disability Index (NDI) in a prediction model of health status six months after a whiplash injury. Both SWE values, measured by two radiologists, and NDI scores were obtained at baseline and after physical therapy (PT) (6-month period). Those values were compared with a 3-point Likert scale (no, partial or full recovery). Twenty-two subjects completed the study. A decrease in trapezius stiffness was detected by both radiologists, statistically significant for one (Δ10.1 kPa; p = 0.04) but not for the second radiologist (Δ8.63 kPa; p = 0.07). The measurements showed excellent intra-observer (ICC 0.75–0.94) and inter-observer (ICC 0.78–0.88) reliability. After six months, fully recovered patients showed lower NDI scores than partially recovered patients (Δ22.98; p < 0.001). SWE values did not differ with the recovery status (55.6 ± 9.7 vs. 57 ± 15.8, Δ1.45; p = 0.82). The single most accurate variable in classifying health status six months after whiplash injury was the relative change of NDI, and it showed the highest accuracy (73.9%) and low Akaike information criterion (AIC = 39.2). Overall, the most accurate classification was obtained when combining NDI and SWE after physical therapy with an accuracy of 77.3% and a decrease in AIC (32.8).

Neck pain in rounded shoulder posture: Clinico-radiologic correlation by shear wave elastography.

The frequency of neck pain increases in adolescents and young adults. Using smart phones and computers for a long time causes posture disorders such as rounded shoulder (RSP) and forward head postures, and these posture disorders cause neck pain. The aim of the study is to analyse the correlation between shoulder and neck angles and the stiffness of the upper trapezius and pectoralis minor muscles in patients with RSP. Patients with neck pain examined by shear wave elastography were screened retrospectively. Patients with RSP were determined. Of these patients, whose had evaluated for shoulder and neck angles with a smart phone-based photogrammetric method were assigned. Patients with a history of operation/trauma, connective tissue or neurological disease were excluded. A total of 39 female patients were included in the study. Age, height, weight, elastography measurements, cervical and shoulder angles were noted. Obtained data were statistically analysed with SPSS 22.0 program. Cervical and shoulder angles of the patients were 52.2±3.8 and 57.91±9.4, respectively. The stiffness of the right and left upper trapezius muscles and right and left pectoralis minor muscles were 42.5±14.1, 47.1±17.1, 20.5±8.0 and 17.9±8.4, respectively. In multiple regression analysis, it was observed that the stiffness of the left upper trapezius muscle was positively correlated with the shoulder angle. The upper trapezius muscle stiffness increased in RSP. It can reveal the relationship between RSP and neck pain.

Is early diagnosis of myofascial pain syndrome possible with the detection of latent trigger points by shear wave elastography?

PurposeThe aim of the study was to investigate the contribution of shear wave elastography to the diagnosis of myo-fascial pain syndrome (MPS) of the upper part of the trapezius.Material and methodsEthical committee approval was obtained for the study. Thirty volunteer women with trigger points in the upper part of the trapezius muscle and 30 healthy women with a similar age distribution were included in the study. The patient group performed a self-stretching exercise program for 4 weeks. No intervention was applied to the control group. Muscle stiffness values of both groups were evaluated with shear wave elastography (SWE), and pain levels of all volunteers were evaluated by the Visual Analogue Scale at the beginning and the end of the study. The statistical analyses were performed using SPSS version 18.0.ResultsThere was a significant decrease after the treatment in terms of upper trapezius muscle stiffness and the pain levels in the patient group (p < 0.001 and p < 0.001). In the patient group, there was a moderate correlation between the decrease in the pain level and the reductions in muscle stiffness (r = 0.595). In control group, there was no significant difference in terms of both muscle stiffness and pain levels before and after treatment (p > 0.05).ConclusionsSWE is a reliable method for detecting latent trigger points in MPS, and it can be used for evaluating the response to treatment.

Eccentric Exercise Reduces Upper Trapezius Muscle Stiffness Assessed by Shear Wave Elastography and Myotonometry.

In this study, we tested the hypotheses that unaccustomed eccentric exercise (ECC) would reduce the elastic modulus and dynamic stiffness of the upper trapezius muscle and that these changes would correlate with increases in muscle thickness, reflecting muscle edema. Shear wave elastography was used to measure elastic modulus, dynamic stiffness was assessed using myotonometry, and muscle thickness was measured using ultrasonography. All measurements were performed at four locations over the upper trapezius before and 24 h after a single bout of ECC. Fourteen healthy participants (11 males and 3 females; 23.2 ± 3.0 years; height 175.1 ± 10.4 cm; body mass 73.8 ± 11.3 kg) took part in the study. Overall, ECC resulted in decreased elastic modulus (from 45.8 ± 1.6 to 39.4 ± 1.2 kPa, p < 0.01) and dynamic muscle stiffness (from 369.0 ± 7.3 to 302.6 ± 6.0 N/m, p < 0.01). Additionally, ECC resulted in increased muscle thickness (from 6.9 ± 0.4 to 7.3 ± 0.4 mm, p < 0.01). Spatial changes (across the four locations) were found for elastic modulus, stiffness and thickness. No significant correlations were found between changes in measures of muscle stiffness, or between changes in stiffness and changes in thickness. In conclusion, the present pilot study showed that ECC altered biomechanical muscle properties, reflected by decreased elastic modulus and dynamic muscle stiffness 24 h after ECC.

Shear-wave elastography for assessment of trapezius muscle stiffness: Reliability and association with low-level muscle activity.

PurposeShear-wave elastography has been recognized a useful tool for quantifying muscle stiffness, commonly reported as shear modulus, however the reports on reliability are often limited to test-retest correlations. In this study, we explored the reliability of shear-wave elastography for assessment of the trapezius muscle stiffness and its relationship with low-level muscle activity.MethodsTwenty participants were included in a two-session experiment. Measurements of shear modulus and muscle activity were performed at rest and during low-level activity, induced by shoulder abduction without additional external resistance.ResultsGood to excellent intra-session repeatability (ICC > 0.80) and moderate inter-rater and inter-session reproducibility (ICC = 0.66–0.74) were observed. Typical errors were acceptable (7.6% of the mean value) only for intra-session measurements in resting conditions, but not acceptable for all conditions with low-level muscle activity (10.2–16.6% of the mean value). Inverse relationships between shear modulus and muscle activity at 40° and 60° of shoulder abduction (r = -0.53 and -0.57) were observed on a group level. We also found higher shear modulus in males compared to females, for the parallel probe position compared to the perpendicular position (in relation to muscle fiber orientation), and for the dominant side of the body compared to the non-dominant side.ConclusionsThis study showed an inverse relationship between muscle activity in low-level range and shear modulus on a group level, suggesting inherent passive stiffness could account for a larger portion of the variance (compared to muscle activity) in shear modulus when the muscle activity is low. Our results imply that shear-wave elastography can be used in research exploring muscle stiffness, however, caution is needed since only intra-session examination in resting conditions showed acceptable within-participant typical errors. The secondary analyses of the study showed higher shear modulus for males, for the non-dominant side of the body and for the parallel orientation of the ultrasound probe.

Quantification of Upper Trapezius Muscle Stiffness Using Supersonic Shear Wave Imaging: Efficacy of Workplace-based Exercise Programme to Reduce Neck and Shoulder Disorders in Working Population

Quantification of Upper Trapezius Muscle Stiffness Using Supersonic Shear Wave Imaging: Efficacy of Workplace-based Exercise Programme to Reduce Neck and Shoulder Disorders in Working Population

Modulation in Elastic Properties of Upper Trapezius with Varying Neck Angle

Background Neck and shoulder complaints caused by poor posture may influence upper trapezius stiffness. The relationship between the shear elastic modulus of the upper trapezius and cervical flexion angles is unknown. Therefore, it is essential to assess upper trapezius stiffness during cervical flexion. The objectives of this study were to (1) determine the intra- and interoperator reliabilities of evaluating upper trapezius stiffness and calculate the minimal detectable change (MDC); (2) examine the elastic modulus alterations of the upper trapezius during cervical flexion; and (3) explore the difference of upper trapezius stiffness between the dominant and nondominant sides. Methods Twenty healthy male participants were recruited in this study. The shear modulus of the upper trapezius was evaluated by two independent investigators using shear wave elastography (SWE) during cervical flexion at 0° and 50°. Findings The intraoperator (intraclass correlation coefficient (ICC) = 0.85–0.86) and interoperator (ICC = 0.94–0.98) reliabilities for measuring the shear elastic modulus of the upper trapezius during the cervical flexion ranged from good to excellent. An increase of 35.58% in upper trapezius stiffness was found at 0° to 50° of cervical flexion, and the MDC was 7.04 kPa. In addition, a significant difference was obtained in the elastic modulus of the upper trapezius muscle between the dominant and nondominant sides (P < 0.05). Conclusions Our findings revealed that SWE could quantify the elastic modulus of the upper trapezius and monitor its changes. Therefore, further studies are required to delineate the modulation in upper trapezius muscle stiffness among subjects with neck and shoulder pain.

Changes in Muscle Stiffness of the Trapezius Muscle After Application of Ischemic Compression into Myofascial Trigger Points in Professional Basketball Players.

The study aimed to assess the effects of compression trigger point therapy on the stiffness of the trapezius muscle in professional basketball players (Part A), and the reliability of the MyotonPRO device in clinical evaluation of athletes (Part B). Twelve professional basketball players participated in Part A of the study (mean age: 19.8 ± 2.4 years, body height 197 ± 8.2 cm, body mass: 91.8 ± 11.8 kg), with unilateral neck or shoulder pain at the dominant side. Part B tested twelve right-handed male athletes (mean ± SD; age: 20.4 ± 1.2 years; body height: 178.6 ± 7.7 cm; body mass: 73.2 ± 12.6 kg). Stiffness measurements were obtained directly before and after a single session trigger point compression therapy. Measurements were performed bilaterally over 5 points covering the trapezius muscle. The effects were evaluated using a full-factorial repeated measure ANOVA and the Bonferroni post-hoc test for equal variance. A p-value < .05 was considered significant. The RM ANOVA revealed a significant decrease in muscle stiffness for the upper trapezius muscle. Specifically, muscle stiffness decreased from 243.7 ± 30.5 to 215.0 ± 48.5 N/m (11.8%), (p = .008) (Part A). The test-retest relative reliability of trapezius muscle stiffness was found to be high (ICC from 0.821 to 0.913 for measurement points). The average SEM was 23.59 N/m and the MDC 65.34 N/m, respectively (Part B). The present study showed that a single session of compression trigger point therapy can be used to significantly decrease the stiffness of the upper trapezius among professional basketball players.

Study on Change of Muscle Tone and Stiffness According to upper trapezius Mild Pain tf young Adults

The purpose of this study was to compare the muscle tone of younger adults with mild pain in upper trapezius muscle The subjects were composed of 90 young college students (M =26, F =64) with mild or no pain in upper trapezius. The degree of mild pain was divided into four groups of 10 point visual analog scale (VAS) 0, 1, 2, and 3 to compare muscle tone and stiffness. The subjects were measured pain (VAS), muscle tone, and stiffness of the trapezius in resting supine position. Statistical analysis was performed using one way ANoVA, correlation, and regression analysis on SPSS 24.0 version. There were statistically significant difference between groups in muscle tone and stiffness of trapezius (p<0.05). In the post hoc analysis, there was a difference between the VAS 3 group and the other groups. Correlation studies showed a correlation between pain, muscle tone and stiffness. The results of the regression analysis showed that the higher the pain and stiffness, the greater the muscle tone. Therefore, the difference in muscle tone due to pain was found in VAS 3 or higher and showed a strong relationship with muscle stiffness. In the future, the relationship between more severe pain and muscle tone will be needed.

Assessing the viscoelastic properties of upper trapezius muscle: Intra- and inter-tester reliability and the effect of shoulder elevation

BackgroundIncreasing stiffness in the upper trapezius muscle may contribute to imbalance of scapular motion, and result in shoulder and neck discomfort during shoulder flexion. Therefore, it is essential to quantify upper trapezius stiffness in various shoulder positions in order to aid in the prevention of these disorders and to optimize rehabilitation. ObjectivesThe objectives of the present study were to examine the intra and inter-tester reliability of MyotonPRO device in measuring upper trapezius stiffness and its ability to determine changes in stiffness during shoulder flexion. MethodsTwenty healthy male subjects (mean age: 28.3±4.8 years) were studied. The stiffness of upper trapezius was quantified using the MyotonPRO device. ResultsThe results revealed excellent intra and inter-tester reliability for measuring upper trapezius stiffness with the shoulder in a neutral position, and also found a 14.2% increase in stiffness upon shoulder flexion between 0° and 60° of flexion. Minimal detectable change (MDC) was 26.3 N/m. ConclusionsOur findings indicate that MyotonPRO device is a feasible tool to quantify upper trapezius stiffness as well as changes in muscle stiffness. Thus, it is important to assess the changes in upper trapezius muscle stiffness due to pathology or treatments for future studies.