Rehabilitative ultrasound imaging of the lower trapezius muscle: technical description and reliability

Reproducibility of subscapularis muscle thickness measurement using ultrasound imaging. -Relationship between subscapularis muscle thickness and internal rotation torque of the shoulder joint

BACKGROUND

Few studies have reported on the morphometry of the subscapularis muscle using ultrasound imaging (USI); and their reproducibility has not been verified.

OBJECTIVES

This study aimed to clarify the relative and absolute reproducibility of USI measurements of subscapularis muscle thickness at rest and during isometric contraction as well as the degree of change in muscle thickness caused by the amount of internal rotational torque in the shoulder joint.

DESIGN

Two-group repeated-measures study.

METHODS

The subjects were the inferior fibers of the subscapularis muscle of 40 healthy adult males. Muscle thickness was measured at rest and at 10%-30% of the maximum isometric internal rotation torque. Intraclass correlation coefficients (ICC) and Brand Altman analysis were used for reproducibility measurement. The degree of change in muscle thickness at each torque was also calculated.

RESULTS

Intra- and inter-rater ICCs (ranged from 0.69 to 0.91) were good. A proportional error was observed in intra-rater measurements. Both minimal detectable change 95 (ranged from 2.33 to 6.47) were high. The subscapularis muscle thickness was significantly increased at 10% torque (25.49 ± 3.80 mm), 20% torque (26.07 ± 3.90 mm), and 30% torque (25.96 ± 3.82 mm) as compared to that in resting conditions (24.53 ± 4.46 mm) (p < 0.05).

CONCLUSION

The reproducibility and error of the subscapularis muscle thickness measurement using USI used in this study were clarified when repeated measurements were made in the same limb position and under the same probe installation conditions, suggesting that the contraction of the subscapularis muscle can be estimated by muscle thickness measurement.

Ultrasound measures of muscle morphology in people with multiple sclerosis are associated with muscle performance and functional mobility

BACKGROUND

Neurologically-based muscle weakness is a common symptom in people with multiple sclerosis MS (MS), who may also exhibit muscle morphology changes and intrinsic muscle dysfunction. Diagnostic ultrasound (sonography) is a non-invasive, inexpensive, and clinically feasible method to measure muscle morphology. The purpose of this study was to investigate possible asymmetries in lower limb muscle morphology and performance in people with MS, and to assess the relationships of muscle morphology measures with individual patient characteristics, muscle performance, and functional mobility.

METHODS

This cross-sectional study was conducted at the Washington, DC Veterans Affairs Medical Center. The study participants were 29 Veterans with MS (52% female, 79% African-American, 48.6 ± 11.2 years old, Mean Expanded Disability Status Scale: 3.6 ± 1.4) who completed seated knee extension isokinetic strength and power tests, functional assessments (Timed 25-Foot Walk - T25FW, 5-Times Sit-to-Stand - 5STS), and quantitative B-mode ultrasound image acquisition of the rectus femoris muscle to derive morphology measures (thickness and echogenicity). The limb with weaker knee extension strength was identified as the more-involved limb. Differences between the more and less-involved limb were quantified using a t-test for all muscle morphology and muscle performance measures. Relationships between muscle morphology and patient characteristics, muscle performance, and functional mobility were evaluated using bivariate and multivariate analyses.

RESULTS

The rectus femoris thickness from the more-involved limb was lower (p<0.001) than that of the less-involved limb, whereas echogenicity was not different between the two limbs (p=0.147). Rectus femoris thickness of the more-involved limb was directly related to age (r=-0.63, p<0.001), muscle strength (r=0.53, p=0.003) and power (r=0.53, p=0.003), and gait speed (r=0.42, p=0.024); whereas its echogenicity was positively associated only with muscle strength (r=-0.46, p=0.013) and power (r=-0.50, p=0.006). Together rectus femoris thickness and echogenicity of the more involved limb explained 44% and 48% of the variance in muscle strength and power, respectively (p<0.001).

CONCLUSION

This study supports the ability of sonography to measure muscle morphology in people with MS, identify asymmetries, and quantify associations with important clinical correlates. Compared with more invasive and costly alternatives, sonography is a clinically feasible, relatively low-cost tool that can be used to assess muscle morphology in people with MS. Further research is warranted to determine the potential clinical utility of sonographic measures of muscle morphology in evaluating changes due to disease progression or therapeutic interventions in this population.

Validation of the Measuring Protocol for the Infraspinatus Muscle with M-Mode Ultrasound in Asymptomatic Subjects. Intra- and Inter-examiner Reliability Study

M-mode ultrasound is a reliable and valid instrument for assessing muscle activity. However, it has not been studied in any of the muscles belonging to the shoulder joint complex, particularly in the infraspinatus muscle. The aim of this study is the validation of the infraspinatus muscle activity measurement protocol with the M-mode ultrasound in asymptomatic subjects. Sixty asymptomatic volunteers were evaluated by two physiotherapists who were blinded; each of them carried out three measurements with the M-mode ultrasound in infraspinatus muscle and analysed the muscle thickness at rest and contraction, velocity of muscle activation and relaxation and Maximum Voluntary Isometric Contraction (MVIC). Intra-observer reliability was significant in both observers, showing good thickness at rest (ICC = 0.833-0.889), thickness in contraction (ICC = 0.861-0.933) and MVIC (ICC = 0.875-0.813); moderate in the activation velocity (ICC = 0.499-0.547) and relaxation velocity (ICC = 0.457-0.606). The inter-observer reliability also had good thickness at rest (ICC = 0.797), thickness in contraction (ICC = 0.89) and MVIC (ICC = 0.84); poor in relaxation time variable (ICC = 0.474) and not significant at the activation velocity (ICC = 0). The muscle activity measurement protocol of the infraspinatus muscle measured with M-mode ultrasound has been found to be reliable in asymptomatic subjects, for both the intra-examiner and inter-examiner.

Lower trapezius muscle function in people with and without shoulder and neck pain: a systematic review

CONTEXT

Shoulder and neck pain are leading causes of disability worldwide. Rotator cuff pathology has strong associations with such pain and is extensively targeted by healthcare practitioners. A dysfunctional lower trapezius muscle has also been shown to contribute to neck and shoulder pain, yet it is often overlooked.

OBJECTIVES

This systematic review analyzes those with a history of, or who are currently managing, shoulder or neck pain to indicate differences in measures of lower trapezius function when compared to subjects without that pain.

METHODS

Studies with no age restrictions were included in the study. Studies could determine lower trapezius muscle function with any quantifiable measurement tool or clinical assessment. If the study included a control group (no pain) and a comparator group (pain), and if lower trapezius muscle function was assessed in both, the study was typically included. The significance of the lower trapezius muscle function change was summarized in these pain patients. From a final total of 18 studies identified, level of muscle activity, muscle activation, time to onset, muscle strength, and muscle thickness were reported.

RESULTS

The 18 included articles involved 485 participants with shoulder and/or neck pain and 455 without. Half of the shoulder pain studies (6/12), and all of the neck pain studies (6/6), demonstrated that the lower trapezius had a noticeable impact. The lower trapezius muscle in participants with shoulder and neck pain tended to show decreased muscle strength, and decreased time to onset/latency.

CONCLUSIONS

The findings from this systematic review should be taken into consideration when assessing and treating patients with shoulder and neck pain. Future studies that define the type and duration of shoulder and neck pain, as well as prospectively assessing lower trapezius muscle function in those with and without that pain, are needed.

Chronic Effects of Pitching on Muscle Thickness and Strength of the Scapular Stabilizers in Professional Baseball Players

BACKGROUND

The posterior scapular muscles eccentrically contract to disperse the high forces observed in the deceleration phase of pitching. Muscular adaptations often occur following chronic eccentric loading, however, no study has evaluated the adaptations of the posterior scapular muscles with regard to throwing and their relationship with humeral retroversion (HR) in professional pitchers.

HYPOTHESIS

Significant chronic adaptations in muscle thickness (MT) and strength of the trapezius and rhomboids would be observed in healthy professional baseball pitchers, and there would be a significant relationship between humeral adaptations (ie, HR) and posterior scapular muscle adaptations (ie, strength and MT).

STUDY DESIGN

Cross-sectional; Level 3.

METHODS

A total of 28 healthy male professional baseball pitchers (age, 22 ± 2 years; mass, 95 ± 17 kg; height, 190 ± 7 cm) were included in the study. Bilateral isometric muscle strength of the upper trapezius (UT), middle trapezius, lower trapezius (LT), and rhomboids was measured during a maximum voluntary isometric contraction. Diagnostic ultrasound images of the UT, middle trapezius, LT, rhomboid major, and rhomboid minor muscles were collected bilaterally to measure MT. HR was also quantified bilaterally with ultrasound. Paired sample t tests were used to compare dominant and nondominant strength and MT. Pearson correlation coefficients were used to assess the relationship between HR, isometric strength, and MT.

RESULTS

A significantly increased MT of the LT was found on the dominant arm compared with the nondominant arm (5.4 ± 1.1 mm vs 4.4 ± 1.5 mm; P = 0.00). The Pearson correlation coefficient demonstrated a significant weak negative relationship between HR and rhomboid major MT (P = 0.03; R = -0.36), and a significant weak negative correlation between HR and middle trapezius isometric strength (P = 0.03; R = -0.37).

CONCLUSION

LT thickness was greater in the throwing arm compared with the nonthrowing arm of pitchers, suggesting a positive adaptation of the LT. Interestingly, there was a weak negative relationship between HR and both rhomboid major MT and middle trapezius isometric strength. This negative relationship suggests that since increased HR leads to decreased internal rotation range of motion during deceleration, the scapula may be forced into anterior tilt and protraction, which can place excessive eccentric load on the rhomboid major and middle trapezius.

Rehabilitative ultrasound imaging of the levator scapula muscle at rest and during contraction: Technical description and reliability

BACKGROUND

Altered scapular muscle activity is associated with abnormal scapular motions and shoulder pain. Hence, quantification of these activities is a challenging issue.

OBJECTIVES

The purposes of this study were to establish the reliability of measuring levator scapula muscle thickness and to examine how thickness of this muscle changes with contraction.

METHODS

Twenty-one asymptomatic individuals (mean age 22.29 ± 2.17 years) participated in this study. Three separate ultrasound images of the levator scapula muscle were captured at the neck-shoulder junction at rest and during a loaded isometric contraction. The procedures were repeated twice, four to seven days apart to establish intra-rater test-retest reliability. Interclass correlation coefficients (ICC) and standard error of measurement (SEM) were used to determine the reliability, and a paired t-test was performed to examine the difference in muscle thickness between two conditions.

RESULTS

The results demonstrated that intra-examiner reliability was good at rest (ICC = 0.88, SEM = 1.16 mm) and excellent during loaded isometric contraction (ICC = 0.95, SEM = 0.91 mm). Furthermore, the thickness of levator scapula muscle significantly increased from rest to the loaded isometric contraction (Effect size = 1.99, P < 0.001).

CONCLUSION

This study demonstrates that the thickness of the levator scapula muscle can be measured reliably at the neck-shoulder junction. Furthermore, ultrasound measures can reliably detect changes in muscle thickness from rest to a contracted state. Therefore, if the need exists to evaluate muscle morphology before and after any treatment strategy, thickness measurement of levator scapula can be determined reliably using ultrasound.

Elastofibroma presented as shoulder pain in an amateur swimmer: screening for referral in physiotherapy. A case report

Elastofibroma is a benign and rare fibroblast/myofibroblast tumor usually located near the periosteum of the ribs. Patients with elastofibroma can remain asymptomatic or can experience a clicking sensation during shoulder movements, shoulder stiffness, scapular and shoulder pain and dysfunction. Importantly, the symptoms can mimic a musculoskeletal condition being mistaken for orthopedic shoulder joint disease. A 54 years-old amateur swimmer self-referred to physiotherapy for left subscapular and shoulder pain. Concerns from the patient's history that caused suspicion of a medical condition included an insidious onset of nagging deep pain that increased with upper limb exertion and an audible thoracic clunk at arm end range flexion. Deep palpatory examination revealed a mass below the latissimus dorsi and rhomboids further screened by the physiotherapist with Rehabilitative Ultrasound Imaging. The physiotherapist referred the patient to a thoracic surgeon who removed the mass. After an exercise-based physiotherapy management program, the patient returned to previous activities including swimming after 5 months. The challenge for clinicians is to screen patients in whom shoulder pain may be related to non-musculoskeletal conditions. Prompt referral of patients presenting with the suspicion of elastofibroma to an appropriate physician may lead to a timely diagnosis and could avoid expensive and unnecessary rehabilitation procedures.

Neuromuscular ultrasound of the scapular stabilisers in healthy subjects

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HRUS can be used to visualise the muscles stabilizing the scapula and their corresponding nerves.

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We found acceptable intra- and inter-examiner agreements.

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We present HRUS normative data using regression-based prediction formulas.

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To our knowledge, we present the first-time normative data of diameter of the dorsal scapular nerve.

Objectives

To obtain normative high-resolution ultrasound (HRUS) data for thickness of the serratus anterior, the trapezius and the rhomboid major muscles and diameter of their corresponding nerves, the long thoracic, the spinal accessory and the dorsal scapular nerve. Moreover, we aimed to examine intra- and inter-examiner agreement of the HRUS measurements.

Methods

We included 41 healthy subjects. Muscle thickness and nerve diameter were measured bilaterally, resulting in 82 ultrasound measurements for each structure. Normative data were calculated using regression equations for the lower limit of muscle thickness and upper limit of nerve diameter, taking into account various variables. For intra- and inter-examiner agreement, ten subjects underwent two extra ultrasound examinations and Bland-Altman plots were calculated.

Results

This normative data set showed significant correlations between decreasing muscle thickness with increasing age and height and increasing muscle thickness with increasing weight and with male sex. Muscle thickness was larger on the dominant side compared to the non-dominant side for the trapezius and rhomboid muscles, whereas the opposite was found for the serratus anterior muscle. For all nerves, significant correlations were found between decreasing nerve diameter with increasing age and height. Intra-examiner agreement was acceptable in all sites. Inter-examiner agreement was acceptable for all sites but one site for the serratus anterior muscle and long thoracic nerve, and not acceptable for five out of six sites for the trapezius muscle.

Conclusion

This study provides HRUS normative data and intra- and inter-examiner agreement data for muscle thickness and nerve diameter for the muscles stabilizing the scapulae and their corresponding nerves.

Significance

The normative HRUS data reported may be useful in future studies investigating neuromuscular disorders.

M-Mode Ultrasound Examination of Soleus Muscle in Healthy Subjects: Intra- and Inter-Rater Reliability Study

Objective: M-mode ultrasound imaging (US) reflects the motion of connective tissue within muscles. The objectives of this study were to evaluate inter-rater and intra-rater reliability of soleus muscle measurements between examiners with different levels of US experience in asymptomatic subjects and to investigate the level of soleus muscle isometric activity in two positions (knee extended and knee flexed at 30°). Methods: Thirty volunteers without a history of ankle pain were evaluated with US examinations of the soleus muscle. Each muscle was scanned independently by two evaluators. Muscle at rest thickness, maximal isometric contraction thickness, time and velocity measures were detailed and blinded to the other examiner. Results: Intra- and inter-rater reliability at rest, in maximal isometric contraction thickness, contraction time and contraction velocity measures for both positions (extended and flexed knee) were reported from good to excellent for all outcome measurements. The position with the knee extended reported a statistically significant increase in thickness after motion showing 1.33 ± 0.27 mm for measurements at rest thickness with knee extended versus 1.50 ± 0.29 mm for measurements at end thickness with the knee in flexed position (p = 0.001), as well as 1.31 ± 0.23 mm for rest thickness with the knee in flexed position measurements with respect to 1.34 ± 0.24 mm for maximal isometric contraction thickness with extended knee measurements (p = 0.058). Conclusions: This study found that intra- and inter-examiner reliability of M-mode ultrasound imaging of the soleus muscle was excellent in asymptomatic subjects and the soleus muscle activity was different between the position with the knee extended and the position with the knee flexed.

Interrater and Intrarater Reliability and Minimum Detectable Change of Ultrasound for Active Myofascial Trigger Points in Upper Trapezius Muscle in Individuals With Shoulder Pain

OBJECTIVE

We sought to investigate the interrater and intrarater reliability of ultrasound and the minimum detectable change (MDC) for the trigger points (TrPs) active in the upper trapezius (UT) muscle in individuals with shoulder pain.

METHODS

Forty individuals with shoulder pain were investigated for the presence of active TrPs in the UT muscle by means of ultrasound for the parameters of gray scale, muscle thickness of UT muscle at rest, and contraction and area of TrPs. The intrarater reliability was performed on 2 days, and interrater reliability on the same day. For the gray scale, the reliability was evaluated using the kappa coefficient (κ), while the other parameters were measured by the intraclass correlation coefficient (ICC), standard error of measurement (SEM), and MDC.

RESULTS

For the gray scale, the intrarater agreement was almost perfect (κ = 1.00) and the interrater agreement was substantial (κ = 0.75). The intrarater and interrater reliability were excellent for most of the parameters, except for the area of TrPs (intrarater: ICC = 0.71, substantial; interrater: ICC = 0.52, substantial). The MDC for intrarater reliability varied between 0.04 and 0.05 (SEM% between 2.4% and 38.87%), and that for interrater reliability ranged from 0.05 to 0.07 (SEM% between 3.18% and 55.10%), with a higher value for area.

CONCLUSION

Parameters such as gray scale, resting muscle thickness, and muscle contraction of the UT muscle, obtained through ultrasound, showed excellent intrarater and interrater reliability with low SEM%. The intrarater and interrater reliability for the area deserves a caveat regarding their use.

Enhancing Trigger Point Dry Needling Safety by Ultrasound Skin-to-Rib Measurement: An inter-Rater Reliability Study

Dry needling (DN) is a minimally invasive treatment technique widely used by physical therapists to treat myofascial trigger points (MTrP). Even if its safety has been commonly declared and the majority of adverse events are considered mild, serious adverse events cannot be excluded and DN treatments of several trunk muscles can potentially result in pneumothorax. Ultrasound imaging (US) skin-to-rib measurement could ensure the safety of this treatment procedure. Therefore, the aim of this study was to determine the inter-rater reliability of depth measurement of different trunk muscles (i.e., rhomboid, lower trapezius, iliocostalis, and pectoralis major) between an expert and two novice physiotherapists. Skin-to-rib distance of 26 asymptomatic and normal weights subjects was consecutively, independently, and randomly measured for each muscle by the three examiners (1 expert and 2 novice physical therapists) with a handheld US wireless probe. Intraclass correlation coefficient (ICC_3,k) and standard error of measurement (SEM) were used to assess inter-rater reliability. Inter-rater reliability of skin-to-rib measurements between the three examiners was good to excellent or excellent for every muscle, with an ICC_3,k ranging from 0.92 and 0.98 (95% CI 0.86–0.99). The SEM never exceeded 10% of the skin-to-rib distance. In conclusion, skin-to-rib US measurements of the trunk muscles can be reliably performed by novice physical therapists using a handheld US device. These measures could be used as an innovative and reliable technique to improve the safety of some potential dangerous DN treatments.

Effects of Lower Trapezius Strengthening Exercises on Pain, Dysfunction, Posture Alignment, Muscle Thickness and Contraction Rate in Patients with Neck Pain; Randomized Controlled Trial

BACKGROUND Neck pain is reported by many laborers who are at risk of experiencing musculoskeletal disorders due to muscle stiffness and hypokinetics. This study examined the effects of a lower trapezius exercise program on neck pain patients. MATERIAL AND METHODS The design of this study was a randomized controlled trial. A total of 40 neck pain patients participated in this study. Screening tests were performed and assigned to experimental group (n=20) and control group (n=20) using randomization program. Both groups underwent a scapula and thoracic spine stabilization exercise program. In addition, the experimental group implemented the lower trapezius strengthening exercise program. All interventions were applied 3 times per week for 4 weeks. Visual Analogue Scale (VAS), Neck Disability Index (NDI), postural alignment, muscle thickness and contraction rate were compared to evaluate the effect on intervention. RESULTS Both groups showed significant differences in VAS, NDI, and postural alignment before and after intervention (P<0.05). In addition, the experimental group showed more significant difference in the amount of change in NDI and postural alignment values than the control group. The experimental group showed significant improvement in muscle thickness and contraction (P<0.05). CONCLUSIONS A lower trapezius strengthening exercise program is an effective method with clinical significance for reducing the level of neck dysfunction, and improving the postural alignment, muscle thickness, and contraction rate of the lower trapezius muscle.

Validity of Ultrasound Imaging Versus Magnetic Resonance Imaging for Measuring Anterior Thigh Muscle, Subcutaneous Fat, and Fascia Thickness

The aim of the present study was to determine the validity of ultrasound (US) imaging versus magnetic resonance imaging (MRI) for measuring anterior thigh muscle, subcutaneous adipose tissue (SAT), and fascia thickness. Twenty healthy, moderately active participants (aged 49.1 ± 9.74 (36–64) years), underwent imaging of the anterior thigh, using ultrasound and MRI modalities on the same day. Images were analyzed offline to assess the level of agreement between US and MRI measurements. Pearson’s correlation coefficient showed an excellent relationship between US imaging and MRI for measuring muscle (r = 0.99, p < 0.01), SAT (r = 0.99, p < 0.01), and non-contractile tissue (SAT combined with perimuscular fascia) thickness (r = 0.99, p < 0.01). Perimuscular fascia thickness measurement showed a poor correlation between modalities (r = 0.39, p < 0.01). Intra-class correlation coefficients (ICC3,1) also showed excellent correlation of the measurements with ICC = 0.99 for muscle thickness, SAT, and non-contractile tissue, but not for perimuscular fascia, which showed poor agreement ICC = 0.36. Bland and Altman plots demonstrated excellent agreement between US imaging and MRI measurements. Criterion validity was demonstrated for US imaging against MRI, for measuring thickness of muscle and SAT, but not perimuscular fascia alone on the anterior thigh. The US imaging technique is therefore applicable for research and clinical purposes for muscle and SAT.

Ultrasonographic assessment of patellar tendon thickness at 16 clinically relevant measurement sites - A study of intra- and interrater reliability

OBJECTIVES

To determine intra- and interrater reliability of ultrasonographic imaging (USI) measurements of patellar tendon (PT) thickness using 16 measurement sites covering the entire tendon.

DESIGN

Reliability study.

SETTING

Physiotherapy outpatient clinic.

PARTICIPANTS

Twenty healthy and physically active volunteers (9 women). Mean age: 24 years (SD ± 2.73). Mean body mass: 75.8 kg (SD ± 11.8).

MAIN OUTCOME MEASURES

Intraclass correlation coefficient (ICC) and 95% limits of agreement (LOA) in cm and in percentage relative to the mean PT thickness.

RESULTS

Intrarater reliability ranged from 0.59 to 0.87 and 0.59 to 0.93 for examiners I and II, respectively. Interrater reliability ranged from 0.37 to 0.89. Measurement precision for examiner I ranged from 0.05 to 0.09 cm (17.5%-26.7%) while ranging from 0.04 to 0.13 cm (13.3%-38.7%) for examiner II. Interrater measurement precision ranged from 0.07 to 0.15 cm (19.1%-42.5%).

CONCLUSION

In an attempt to replicate daily clinical USI practice, this was the first study extensively assessing reliability throughout the full range of the patellar tendon - revealing a considerable variation in intra- and interrater reliability as well as measurement precision throughout the 16 individual PT sites. In a clinical context, the low interrater reliability and precision found at the proximal tendon insertion site may have implications for USI of the symptomatic PT, as this is the site mainly associated with underlying pathologic changes. Further reliability studies are needed to clarify the region-specific reliability of the full length PT.

Scapular Upward Rotator Morphologic Characteristics in Individuals With and Without Forward Head Posture: A Case-Control Study

OBJECTIVES

There are several reports suggesting that forward head posture contributes to alterations in scapular kinematics and muscle activity, leading to the development of shoulder problems. Currently, it is unknown whether forward head posture alters the thickness of the scapular muscles. The aim of this study was to compare the thickness of the serratus anterior and upper and lower trapezius muscles at rest and during loaded isometric contractions in individuals with and without forward head posture.

METHODS

Twenty individuals with forward head posture and 20 individuals with normal head posture participated in this case-control study. Three separate ultrasound images of the serratus anterior and upper and lower trapezius muscles were captured under 2 randomized conditions: at rest and during a loaded isometric contraction.

RESULTS

The thickness of each muscle significantly increased from rest to the loaded isometric contraction (P < .001). The only difference between the groups was that the thickness of the serratus anterior muscle at rest in the normal-posture group was larger than that in the forward-posture group (P = .01).

CONCLUSIONS

Forward head posture appears to be related to atrophy of the serratus anterior muscle, which may contribute to the development of shoulder problems. Further research is required to identify more about the association of forward head posture with the imbalance of shoulder girdle muscles and the impact of head posture on upper quadrant pain.

Rehabilitative Ultrasound Imaging Evaluation in Physiotherapy: Piloting a Systematic Review

Background: Research of ultrasound use in physiotherapy and daily practice has led to its use as an everyday tool. Methods: The aims were: (1) Checking the proposed systematic review protocol methodology; (2) evaluating the evidence from the last five years; and (3) coordinating the work of the team of reviewers in performing a complete systematic review. Thus, this is a pilot study prior to a full systematic review. The findings in databases related to health sciences with the meta-search engine Discovery EBSCO, Covidence, and Revman were used. Inclusion and exclusion criteria were described for eligibility. Results: Search provided 1029 references regarding the lumbar region on ultrasound scans. Of these, 33 were duplicates. After Covidence, 996 studies were left for screening. A full-text reading brought one randomized clinical trial (RCT). Conclusions: Validity and reliability references were found. The most suitable points were novice versus expert, and ultrasound versus electromyography (EMG) with just one RCT cohort, and observational and case reports. The lines of investigation increasingly endorsed the validity of using ultrasound in physiotherapy. Post-acquisition image analysis could also be a future line of research.

Reliability of the Upper Trapezius Muscle and Fascia Thickness and Strain Ratio Measures by Ultrasonography and Sonoelastography in Participants With Myofascial Pain Syndrome

Objective

The purpose of this study was to assess the intra- and interexaminer reliability of the upper trapezius muscle and fascia thickness measured by ultrasonography imaging and strain ratio by sonoelastography in participants with myofascial pain syndrome.

Methods

Thirty-two upper trapezius muscles were assessed. Two examiners measured the upper trapezius thickness and strain ratio 3 times by ultrasonography and sonoelastography independently in the test session. The retest session was completed 6 to 8 days later.

Results

A total of 87.5% of participants had trigger points on the right side, and 22.5% had trigger points on the left side. For the test session, the average upper trapezius thickness, fascia thickness, and strain ratio measured by first and second examiners were 11.86 mm and 11.56 mm, 1.23 mm and 1.25 mm, and 0.94 and 0.99, respectively. For the retest session, the previously mentioned parameters obtained by first and second examiners were 11.76 mm and 11.39 mm, 1.27 mm and 1.29 mm, and 0.96 and 0.99, respectively. The intraclass correlation coefficients indicated good to excellent reliability for both within-intraexaminer (0.78-0.96) and between-intraexaminer (0.75-0.98) measurements. Also, the intraclass correlation coefficients and standard errors of measurement of interexaminer reliability ranged between 0.88 to 0.93 and 0.05 to 0.44 for both muscle and fascia thickness and 0.70 to 0.75 and 0.04 to 0.20 for strain ratio of upper trapezius, respectively.

Conclusion

Upper trapezius thickness measurements by ultrasonography and strain ratio by sonoelastography are reliable methods in participants with myofascial pain syndrome.

Neuromuscular ultrasound for evaluation of scapular winging

INTRODUCTION

Clinicians who treat nerve and muscle disorders may be asked to evaluate patients who have unilateral or bilateral scapular winging. Traditionally, this evaluation has relied upon a thorough history, physical examination, and electrodiagnostic testing to localize the cause of winging and detect the underlying neuromuscular pathology. Neuromuscular ultrasound has emerged as a non-invasive technique that can be used for structural evaluation of nerve and muscle abnormalities.

METHODS

Previous studies of imaging in scapular winging and experiences from our diagnostic laboratory are reviewed.

RESULTS

Four standard and 4 ancillary ultrasound views are described for evaluation of scapular winging.

CONCLUSION

Ultrasound is a non-invasive, painless, and radiation-free technology that can be used to evaluate scapular winging. Muscle Nerve 56: 7-14, 2017.

The Need for Standardized Assessment of Muscle Quality in Skeletal Muscle Function Deficit and Other Aging-Related Muscle Dysfunctions: A Symposium Report

A growing body of scientific literature suggests that not only changes in skeletal muscle mass, but also other factors underpinning muscle quality, play a role in the decline in skeletal muscle function and impaired mobility associated with aging. A symposium on muscle quality and the need for standardized assessment was held on April 28, 2016 at the International Conference on Frailty and Sarcopenia Research in Philadelphia, Pennsylvania. The purpose of this symposium was to provide a venue for basic science and clinical researchers and expert clinicians to discuss muscle quality in the context of skeletal muscle function deficit and other aging-related muscle dysfunctions. The present article provides an expanded introduction concerning the emerging definitions of muscle quality and a potential framework for scientific inquiry within the field. Changes in muscle tissue composition, based on excessive levels of inter- and intra-muscular adipose tissue and intramyocellular lipids, have been found to adversely impact metabolism and peak force generation. However, methods to easily and rapidly assess muscle tissue composition in multiple clinical settings and with minimal patient burden are needed. Diagnostic ultrasound and other assessment methods continue to be developed for characterizing muscle pathology, and enhanced sonography using sensors to provide user feedback and improve reliability is currently the subject of ongoing investigation and development. In addition, measures of relative muscle force such as specific force or grip strength adjusted for body size have been proposed as methods to assess changes in muscle quality. Furthermore, performance-based assessments of muscle power via timed tests of function and body size estimates, are associated with lower extremity muscle strength may be responsive to age-related changes in muscle quality. Future aims include reaching consensus on the definition and standardized assessments of muscle quality, and providing recommendations to address critical clinical and technology research gaps within the field.

Age-Related Changes in Morphology and Function of Scapular Muscles in Asymptomatic People

BACKGROUND

Aging is a contributing factor to rotator cuff tears. Dysfunction of the scapular muscles can be a potential cause of rotator cuff tears. Although aging can contribute to dysfunction of the scapular muscles and subsequently result in rotator cuff tears, the effects of aging on scapular muscles are unclear.

OBJECTIVE

To determine changes in sizes and electromyographic activities of the scapular muscles with age in asymptomatic subjects.

DESIGN

Cross-sectional study.

PATIENTS

Fifty-four asymptomatic subjects without shoulder pain and dysfunction (18 male and 36 female) were recruited for this study. Subjects consisted of 19 people aged 20-39 years (young adult group, 27.2 ± 5.2 years), 17 people aged 40-59 years (middle age group, 49.9 ± 6.6 years), and 18 people aged 60-79 years (elderly group, 68.0 ± 7.1 years).

METHODS

Using ultrasonography, we measured the muscle thickness of the trapezius (upper and lower portions), serratus anterior, and middle deltoid muscles during rest with the subject in a sitting position. Activities of the same muscles were measured with surface electromyography during shoulder elevation in the scapular plane up to 120°. The electromyographic data were analyzed at ranges 0°-30°, 30°-60°, and 60°-90°. Analysis of variance and Bonferroni multiple comparisons were used for statistical analysis.

RESULTS

Muscle thickness of the lower trapezius in the elderly group was decreased significantly compared with that in the young adult group (95% confidence interval -0.40, 2.24; P < .001) and middle age group (95% confidence interval -0.34, 1.89; P = .012). There were no significant differences in muscle activity and activity ratio between groups.

CONCLUSION

In scapular muscles, muscle thickness of the lower trapezius significantly decreased with aging, although there were no decreases in muscle thicknesses of the other muscles between different age groups. For the functional change, aging may not affect the scapular muscle activities and balance of the activities between the deltoid and scapular muscles.

LEVEL OF EVIDENCE

IV.

Ultrasound imaging in women's arm flexor muscles: intra-rater reliability of muscle thickness and echo intensity

Background

Different ultrasound parameters have been frequently used to assess changes associated with training, aging, immobilization, and neuromuscular diseases. However, an exploratory reliability analysis of the echo intensity (EI) and muscle thickness (MT) of the forearm flexors is scarce, especially in women.

Objective

The purpose of the present study was to determine the intra-rater reliability of MT and EI assessed by ultrasound in young women.

Method

Ultrasonographic MT and EI were acquired in the forearm flexors of 41 young women (22±2 yrs). Reliability was calculated using intraclass correlation coefficient (ICC_2,1), standard error of measurement (SEM), coefficient of variation (CV), smallest detectable change (SDC), and Bland and Altman plot analysis.

Results

ICC values for MT and EI were 0.88 (95% CI: 0.78-0.93). The SEM and CV values were lower than 10%. Bland and Altman analysis revealed that ultrasound mean differences were 0.27 mm (Limits of Agreement - LOA 95%: - 2.6 to 3.2 mm) and -0.09 a.u. (LOA 95%: - 10.9 to 10.7 a.u.).

Conclusion

MT and EI assessed by ultrasonography in young women appear to be reliable and may be used to monitor changes in muscle mass induced by strength training when these changes exceed the precision of ultrasound.

Ultrasonography for the assessment of the upper trapezius properties in healthy females: a reliability study

BACKGROUND

to date, an assessment of morphometric features, muscle stiffness and blood flow in the upper trapezius among healthy females at rest and contraction states has not been conducted. So, in the current research, the intra-rater reliability of ultrasonographic features of upper trapezius in healthy females was examined.

METHOD

in this study stiffness and thickness of the upper trapezius in rest and contraction states were measured by ultrasonography on 12 healthy female subjects (28.33±5.05 years old). Color Doppler imaging was used to assess muscle circulation in the rest state only. Every step and calculation of measurements was repeated 3 times with the same rater. Therefore, in total 36 measurements were done for each variable.

RESULTS

according to the analysis, the value of intra class correlation coefficient (ICC) for total variables showed an excellent level of reliability. Thickness at contraction had maximum reliability (ICC= 0.993) and Minimum Diastolic Velocity had the lowest reliability (ICC=0.771).

CONCLUSIONS

the results of current research demonstrated that real time ultrasonography is a reliable method for measurement of various parameters of upper trapezius, including morphometric features, its stiffness and blood supply in non-symptomatic females. These mentioned variables can likely be used for objective assessment and provide numerical reference value for clinical plans.

Interrater reliability of quantitative ultrasound using force feedback among examiners with varied levels of experience

Background. Quantitative ultrasound measures are influenced by multiple external factors including examiner scanning force. Force feedback may foster the acquisition of reliable morphometry measures under a variety of scanning conditions. The purpose of this study was to determine the reliability of force-feedback image acquisition and morphometry over a range of examiner-generated forces using a muscle tissue-mimicking ultrasound phantom.

Methods. Sixty material thickness measures were acquired from a muscle tissue mimicking phantom using B-mode ultrasound scanning by six examiners with varied experience levels (i.e., experienced, intermediate, and novice). Estimates of interrater reliability and measurement error with force feedback scanning were determined for the examiners. In addition, criterion-based reliability was determined using material deformation values across a range of examiner scanning forces (1–10 Newtons) via automated and manually acquired image capture methods using force feedback.

Results. All examiners demonstrated acceptable interrater reliability (intraclass correlation coefficient, ICC = .98, p < .001) for material thickness measures obtained using force feedback. Individual examiners exhibited acceptable reliability with the criterion-based reference measures (ICC > .90, p < .001), independent of their level of experience. The measurement error among all examiners was 1.5%–2.9% across all applied stress conditions.

Conclusion. Manual image capture with force feedback may aid the reliability of morphometry measures across a range of examiner scanning forces, and allow for consistent performance among examiners with differing levels of experience.

Decreased thickness of the lower trapezius muscle in patients with unilateral neck pain

INTRODUCTION

Thickness of the lower trapezius muscle in patients with neck pain has not been established. We examined the thickness of the lower trapezius muscle in patients with and without unilateral neck pain.

METHODS

Twenty women with unilateral (right) neck pain and 20 matched controls participated in the study. Thickness of the lower trapezius muscles was measured bilaterally at rest (0 ° and 120 ° of shoulder abduction) and during contraction (120 ° of shoulder abduction) using ultrasound imaging.

RESULTS

The neck pain group had smaller thickness of the lower trapezius muscle on the painful side compared with controls both at rest and during contraction (P < 0.05). However, the percentage change in the lower trapezius thickness from rest to contraction (120 ° of shoulder abduction) was not different between groups (P > 0.05).

CONCLUSIONS

Patients with neck pain had smaller thickness of the lower trapezius muscle on the painful side compared with healthy controls. Muscle Nerve 54: 439-443, 2016.

Diagnostic ultrasound estimates of muscle mass and muscle quality discriminate between women with and without sarcopenia

Introduction: Age-related changes in muscle mass and muscle tissue composition contribute to diminished strength in older adults. The objectives of this study are to examine if an assessment method using mobile diagnostic ultrasound augments well-known determinants of lean body mass (LBM) to aid sarcopenia staging, and if a sonographic measure of muscle quality is associated with muscle performance.

Methods: Twenty community-dwelling female subjects participated in the study (age = 43.4 ± 20.9 years; BMI: 23.8, interquartile range: 8.5). Dual energy X-ray absorptiometry (DXA) and diagnostic ultrasound morphometry were used to estimate LBM. Muscle tissue quality was estimated via the echogenicity using grayscale histogram analysis. Peak force was measured with grip dynamometry and scaled for body size. Bivariate and multiple regression analyses were used to determine the association of the predictor variables with appendicular lean mass (aLM/ht²), and examine the relationship between scaled peak force values and muscle echogenicity. The sarcopenia LBM cut point value of 6.75 kg/m² determined participant assignment into the Normal LBM and Low LBM subgroups.

Results: The selected LBM predictor variables were body mass index (BMI), ultrasound morphometry, and age. Although BMI exhibited a significant positive relationship with aLM/ht² (adj. R² = 0.61, p < 0.001), the strength of association improved with the addition of ultrasound morphometry and age as predictor variables (adj. R² = 0.85, p < 0.001). Scaled peak force was associated with age and echogenicity (adj. R² = 0.53, p < 0.001), but not LBM. The Low LBM subgroup of women (n = 10) had higher scaled peak force, lower BMI, and lower echogenicity values in comparison to the Normal LBM subgroup (n = 10; p < 0.05).

Conclusions: Diagnostic ultrasound morphometry values are associated with LBM, and improve the BMI predictive model for aLM/ht² in women. In addition, ultrasound proxy measures of muscle quality are more strongly associated with strength than muscle mass within the study sample.

Progressive Resistance Exercise with Eccentric Loading for the Management of Knee Osteoarthritis

INTRODUCTION

The patient was a 58-year-old African-American male with radiographic evidence of bilateral knee osteoarthritis (OA). He participated in a standardized 12-week eccentric strengthening program within a Veterans Affairs (VA) medical center.

BACKGROUND

The use of an eccentric training paradigm may prove to be beneficial for older adults with knee OA since eccentric muscle actions are involved in the energy absorption at the knee joint during gait and controlled movement during stair descent. Furthermore, in comparison to standard muscle actions, eccentric muscle actions result in higher torque generation and a lower rate of oxygen consumption at a given level of perceived exertion. Therefore, this mode of progressive resistance exercise may be ideal for older adults.

DISCUSSION

The patient completed an eccentric strengthening regimen for the knee flexors and extensors twice per week without an exacerbation of knee pain. Muscle morphology measures of the rectus femoris were measured using diagnostic ultrasound. Isokinetic measures of muscle peak torque were obtained at 60°/s and 180°/s. Functional performance was assessed using a physical performance battery and stair-step performance was assessed from the linear displacement of the center of gravity trajectories obtained with a force plate. Visual analog scale pain ratings and self-reported global disease status were also documented. Post-exercise assessments revealed improvements in sonographic muscle size and tissue composition estimates, peak knee extensor torque (ranging from 60 to 253%), functional performance, and global disease status.

CONCLUDING REMARKS

The patient exhibited improvements in muscle morphology, muscle strength, functional performance, pain, and global disease status after 12 weeks of an eccentric strengthening regimen. The intervention and outcomes featured in this case were feasible to implement within a VA medical center and merit further investigation.

Scapular muscle performance in individuals with lateral epicondylalgia

STUDY DESIGN

Descriptive, laboratory-based, cross-sectional study.

OBJECTIVES

To describe scapular musculature strength, endurance, and change in thickness in individuals with unilateral lateral epicondylalgia (LE) compared to the uninvolved limb and the corresponding limb of a matched comparison group.

BACKGROUND

Reported poor long-term outcomes for the nonsurgical management of individuals with LE suggest a less-than-optimal rehabilitation process. Knowledge of scapular muscle function in a working population of individuals with LE may help to further refine conservative management of this condition.

METHODS

Twenty-eight patients with symptomatic LE and 28 controls matched by age and sex were recruited to participate in the study. Strength of the middle trapezius (MT), lower trapezius (LT), and serratus anterior (SA) was measured with a handheld dynamometer. A scapular isometric muscle endurance task was performed in prone. Changes in muscle thickness of the SA and LT were measured with ultrasound imaging. Analysis-of-variance models were used to determine within- and between-group differences.

RESULTS

The involved side of the group with LE had significantly lower values for MT strength (P = .031), SA strength (P<.001), LT strength (P = .006), endurance (P = .003), and change in SA thickness (P = .028) when compared to the corresponding limb of the control group. The involved side of the group with LE had significantly lower strength of the LT (P = .023) and SA (P = .016) when compared to the uninvolved limb; however, these differences were small and of potentially limited clinical significance.

CONCLUSION

When compared to a matched comparison group, there were impairments of scapular musculature strength and endurance in patients with LE, suggesting that the scapular musculature should be assessed and potentially treated in this population. Cause and effect cannot be established, as the weakness of the scapular musculature could be a result of LE.

Current rehabilitation applications for shoulder ultrasound imaging

The available body of knowledge on shoulder ultrasound imaging has grown considerably within the past decade, and physical therapists are among the many health care professions currently exploring the potential clinical integration of this imaging technology and the knowledge derived from it. Therefore, the primary purpose of this commentary was to review the recent evidence and emerging uses of ultrasound imaging for the clinical evaluation of shoulder disorders. This includes a detailed description of common measurement techniques along with their known clinimetric properties. Specifically provided are critical appraisals of the existing measures used to estimate soft tissue and bony morphometry, muscle contractile states, and lean muscle density. These appraisals are intended to help clinicians clarify the scope of physical therapy practice for which these measurement techniques are effectively utilized and to highlight areas in need of further development.

Thickness of the lower trapezius and serratus anterior using ultrasound imaging during a repeated arm lifting task

The purposes of this study were to establish the reliability for measuring scapular muscle thickness, and to examine how scapular muscle thickness changes with respect to external loads. Participants were asymptomatic subjects recruited from a sample of convenience. Thickness Measures were taken using rehabilitative ultrasound imaging (RUSI) under 11 conditions, rest and 10 progressive loads, for the Lower Trapezius (LT) and Serratus Anterior (SA). The procedures were repeated 1 week later to determine reliability. Bland and Altman limits of agreement and Interclass correlation coefficients (ICC) were used to determine reliability. Separate repeated measure ANOVAs were performed to determine differences in muscle thickness for both muscles across 3 conditions; rest and the 2 loaded conditions that represented the lowest and highest torque values. Results demonstrate good within and between day reliability for the LT (ICC = .86 to .99) and SA (ICC = .88 to .99). For the LT and SA, there were significant differences between the resting thickness and 2 lifting conditions (p ≤ .01) but not between the two lifting conditions. It was concluded that RUSI is reliable in measuring scapular muscle thickness. RUSI is sensitive enough to detect absolute changes in thickness from resting to a contracted state but unable to detect differences between loads imposed on the shoulder.

Functional exercise after total hip replacement (FEATHER): a randomised control trial

Background

Prolonged physical impairments in range of movement, postural stability and walking speed are commonly reported following total hip replacement (THR). It is unclear from the current body of evidence what kind of exercises should be performed to maximize patient function and quality of life.

Methods/design

This will be a single blind multi centre randomized control trial with two arms. Seventy subjects post primary total hip arthroplasty will be randomized into either an experimental group (n=35), or to a control group (n=35). The experimental group will attend a functional exercise class twice weekly for a six week period from week 12 to week 18 post surgery. The functional exercise group will follow a circuit based functional exercise class supervised by a chartered Physiotherapist. The control group will receive usual care. The principal investigator (BM) will perform blinded outcome assessments on all patients using validated measures for pain, stiffness, and function using the Western Ontario and Mc Master Universities Osteoarthritis index (WOMAC). This is the primary outcome measurement tool. Secondary outcome measurements include Quality of life (SF-36), 6 min walk test, Visual Analogue Scale, and the Berg Balance score. The WOMAC score will be collated on day five post surgery and repeated at week twelve and week eighteen. All other measurements will be taken at week 12 and repeated at week eighteen. In addition a blinded radiologist will measure gluteus medius cross sectional area using real time ultrasound for all subjects at week 12 and at week 18 to determine if the functional exercise programme has any effect on muscle size.

Discussion

This randomised controlled trial will add to the body of evidence on the relationship between muscle size, functional ability, balance, quality of life and time post surgery in patients following total hip arthroplasty. The CONSORT guidelines will be followed to throughout. Ethical approval has been gained from the Ethics committee Health Services Executive Dublin North East.

Trial registration

This trial is registered with ClinicalTrials.gov (a service of the United States National Institutes of Health) identifier NCT01683201

Ultrasound imaging and muscle function

There is a growing trend in the physical therapy profession to use conventional grayscale brightness (B-mode) ultrasound imaging (USI) as a tool to assess the morphological (form and structure) and morphometric (measures of form) characteristics of muscle, and to use these findings to draw conclusions regarding muscle function. This trend is reflected in numerous published investigations. As many physical therapists may lack training in the principles and instrumentation underlying USI use, it is critical that therapists gain a clear understanding of the information that USI can, and cannot, provide about muscle function before employing the technique for either research or clinical applications. Failure to do so may result in the propagation of inaccurate terminology and beliefs. This paper aims to clarify the role that USI has in the assessment of muscle function, first, by briefly reviewing how conventional grayscale B-mode ultrasound images and clips are generated, and second, by summarizing the types of information that these images can provide. It also discusses the various factors that need to be considered when interpreting a dynamic USI assessment of muscle specifically as it relates to the assessment of muscle function.

Reliability and responsiveness of musculoskeletal ultrasound in subjects with and without spinal cord injury

Rehabilitation after spinal cord injury (SCI) aims to preserve the integrity of the paralyzed musculoskeletal system. The suitability of ultrasound (US) for delineating training-related muscle/tendon adaptations after SCI is unknown. The purpose of this study was to quantify within- and between-operator reliability for US and to determine its responsiveness to post-training muscle/tendon adaptations in SCI subjects. Two novice operators and one experienced operator obtained sonographic images of the vastus lateralis, patellar tendon, soleus, and Achilles tendon from seven SCI subjects and 16 controls. For control subjects, within-operator concordance (ICC [3,1]) ranged from 0.58 to 0.95 for novice operators and exceeded 0.86 for the experienced operator. Between-operator concordance (ICC [2,1]) ranged from 0.62 to 0.74. Ultrasound detected muscle hypertrophy (p < 0.05) following electrical stimulation training in subjects with SCI (responsiveness) but did not detect differences in tendon thickness. These error estimates support the utility of US in future post-SCI training studies.

Validity of real-time ultrasound imaging to measure anterior hip muscle size: a comparison with magnetic resonance imaging

STUDY DESIGN

Clinical measurement, criterion standard.

OBJECTIVES

To investigate the validity of real-time ultrasound imaging (USI) to measure individual anterior hip muscle cross-sectional area.

BACKGROUND

The hip flexor muscles are important for hip joint function and could be affected by joint pathology or injury. Objectively documenting individual anterior hip muscle size can be useful in identifying muscle size asymmetry and monitoring treatment efficacy for patients with hip problems. USI offers a novel method of measuring individual muscle size in the clinic, but its validity in measuring the anterior hip muscles has not been investigated.

METHODS

Nine healthy participants (5 males, 4 females) underwent imaging of their iliopsoas, sartorius, and rectus femoris muscles with USI and magnetic resonance imaging. Bilateral muscle cross-sectional areas were measured on images from both modalities.

RESULTS

There was no significant difference (P>.05) in mean cross-sectional area measurements from USI and magnetic resonance imaging for each muscle. Agreement between measurements was high for the iliopsoas (left: intraclass correlation coefficient [ICC3,1] = 0.86; 95% confidence interval [CI]: 0.51, 0.97; right: ICC3,1 = 0.88; 95% CI: 0.57, 0.97), sartorius (left: ICC3,1 = 0.82; 95% CI: 0.41, 0.96; right: ICC3,1 = 0.81; 95% CI: 0.39, 0.95), and rectus femoris (left: ICC3,1 = 0.85; 95% CI: 0.49, 0.96; right: ICC3,1 = 0.89; 95% CI: 0.61, 0.97). Reliability of measuring each muscle with USI was high between 2 trials (ICCs3,1 = 0.84 to 0.94).

CONCLUSION

USI is a valid measure of iliopsoas, sartorius, and rectus femoris muscle size in healthy people, as long as a strict measurement protocol is followed.

Thickness of the middle trapezius muscle measured by rehabilitative ultrasound imaging: description of the technique and reliability study

A technique is described for measuring the thickness of the middle trapezius muscle using rehabilitative ultrasound imaging (RUSI). A test-retest study was employed to investigate the reliability of the technique in a convenience sample of 16 asymptomatic participants aged 20-41 (12 women). The middle trapezius muscle was imaged using RUSI with participants in a standardized sitting position. The principal investigator took measurements on two consecutive days to examine intra-rater reliability, and two additional investigators took measurements on the second day to investigate inter-rater reliability of the measurement technique. Reliability was examined using intra-class correlation coefficients (ICC), standard error of measurement (SEM), and Bland and Altman plots. The results demonstrated that inter-rater reliability was good between raters (ICC₂,₃ = 0.81, SEM = 0.94 mm) and was moderate for the same rater between days (ICC₃,₂ = 0.67, SEM = 1.0 mm). This study demonstrates that RUSI can be used reliably to measure muscle thickness of the middle trapezius muscle following the procedure described.