Reproducibility and Accuracy of the Radiofrequency Echographic Multi-Spectrometry for Femoral Mineral Density Estimation and Discriminative Power of the Femoral Fragility Score in Patients with Primary and Disuse-Related Osteoporosis.

We aimed to investigate the reproducibility and accuracy of Radiofrequency Echographic Multi-Spectrometry (REMS) for femoral BMD estimation and the reproducibility and discriminative power of the REMS-derived femoral fragility score. 175 patients with primary and disuse-related osteoporosis were recruited: one femoral Dual-energy X-ray Absorptiometry (DXA) scan and two femoral REMS scans were acquired. No significant test-retest differences were observed for all REMS-derived variables. The diagnostic concordance between DXA and REMS was 63% (Cohen's kappa = 0.31) in patients with primary osteoporosis and 13% (Cohen's kappa: -0.04) in patients with disuse-related osteoporosis. No significant difference was observed between REMS and DXA for either femoral neck BMD (mean difference between REMS and DXA: -0.015 g/cm2) or total femur BMD (mean difference: -0.004 g/cm2) in patients with primary osteoporosis. Significant differences between the two techniques were observed in patients with disuse-related osteoporosis (femoral neck BMD difference: 0.136 g/cm2; total femur BMD difference: 0.236 g/cm2). Statistically significant differences in the fragility score were obtained between the fractured and non-fractured patients for both populations. In conclusion, REMS showed excellent test-retest reproducibility, but the diagnostic concordance between DXA and REMS was between minimal and poor. Further studies are required to improve the REMS-derived estimation of femoral BMD.

Digital Anthropometry for Body Circumference Measurements: European Phenotypic Variations throughout the Decades.

This review summarizes body circumference-based anthropometrics that are in common use for research and in some cases clinical application. These include waist and hip circumference-based central body indices to predict cardiometabolic risk: waist circumference, waist-to-hip ratio, waist-to-height ratio, waist-to-thigh ratio, body adiposity index, a body shape index (ABSI), hip index (HI), and body roundness index (BRI). Limb circumference measurements are most often used to assess sarcopenia and include: thigh circumference, calf circumference, and mid-arm circumference. Additionally, this review presents fascinating recent developments in optic-based imaging technologies that have elucidated changes over the last decades in average body size and shape in European populations. The classical apple and pear shape concepts of body shape difference remain useful, but novel and exciting 3-D optical "e-taper" measurements provide a potentially powerful new future vista in anthropometrics.

DXA-Based Detection of Low Muscle Mass Using the Total Body Muscularity Assessment Index (TB-MAXI): A New Index with Cutoff Values from the NHANES 1999-2004.

The aims of this study were to investigate age-related changes in total body skeletal muscle mass (TBSMM) and the between-limb asymmetry in lean mass in a large sample of adults. Demographic, anthropometric, and DXA-derived data of National Health and Nutrition Examination Survey participants were considered. The sample included 10,014 participants of two ethnic groups (Caucasians and African Americans). The age-related decline of TBSMM absolute values was between 5% and 6% per decade in males and between 4.5% and 5.0% per decade in females. The adjustment of TBSMM for body surface area (TB-MAXI) showed that muscle mass peaked in the second decade and decreased progressively during the subsequent decades. The following thresholds were identified to distinguish between low and normal TB-MAXI: (i) 10.0 kg/m2 and 11.0 kg/m2 in Caucasian and African American females; and (ii) 12.5 kg/m2 and 14.5 kg/m2 in Caucasian and African American males. The lean asymmetry indices were higher for the lower limbs compared with the upper limbs and were higher for males compared with females. In conclusion, the present study proposes the TB-MAXI and lean asymmetry index, which can be used (and included in DXA reports) as clinically relevant markers for muscle amount and lean distribution.

Quantitative assessment of volumetric muscle loss: Dual-energy X-ray absorptiometry and ultrasonography.

The generalized skeletal muscle disorder that involves (in elderly subjects) the progressive loss of muscle mass and function has been defined sarcopenia, whereas the rapid-onset (traumatic or surgical) and focal (unilateral) loss of skeletal muscle with resultant functional impairment has been defined volumetric muscle loss. Different tools and approaches are commonly used in the clinical settings to quantify the loss of muscle or lean mass and to assess the consequent motor impairment. This review describes the technical principles and provides a summary of the main parameters that can be obtained to assess lean mass (and its distribution) or muscle size (and its structure) through the two imaging techniques most easily accessible and therefore frequently adopted in the clinical practice: dual-energy X-ray absorptiometry and muscle ultrasonography.

Characterization of the stimulation output of four devices for focal muscle vibration.

Different devices for mechano-acoustic muscle vibration became available on the market in the last ten years. Although the use of these vibrators is increasing in research and clinical settings, the features of their stimulation output were never described in literature. In this study we aimed to quantify and compare the stimulation output of the four most widespread pneumatic devices for focal muscle vibration available on the market. A piezoelectric pressure sensor was used to measure the pressure profile generated by the four selected devices in the following experimental conditions: i) measurement of the output changes associated with variations of the stimulation amplitude for three stimulation frequencies (100 Hz, 200 Hz, and 300 Hz); ii) measurement of the output changes during a 20-min long stimulation at constant frequency (300 Hz) and amplitude; iii) measurement of the output changes associated with the progressive activation of all stimulation channels at constant frequency (200 Hz) for different amplitudes. The maximum peak-to-peak amplitudes of the pressure waves were in the range 102 mbar - 369 mbar (below the maximum values declared by the different manufacturers). The shape of the pressure waves generated by the four devices was quasi-sinusoidal and asymmetric with respect to the atmospheric pressure. All output features had a remarkable intra- and inter-device variability. Further studies are required to support the technological improvement of the currently available devices and to focus the issues of vibration effectiveness, limitations, proper protocols, modalities of its application and assessment in neuromuscular training and rehabilitation.

Effectiveness of a home-based telerehabilitation system in patients after total hip arthroplasty: study protocol of a randomized controlled trial.

BACKGROUND: The demand for total hip arthroplasty (THA) is quickly rising given the escalating global incidence of hip osteoarthritis, and it is widely accepted that the post-surgery rehabilitation is key to optimize outcomes. The overall objective of this study is to evaluate the effectiveness of a new telerehabilitation solution, ReHub, for the physical function and clinical outcome improvement following THA. The specific aims of this manuscript are to describe the study design, protocol, content of interventions, and primary and secondary outcomes and to discuss the clinical rehabilitation impact of the expected experimental results. METHODS/DESIGN: This prospective, randomized, controlled, parallel-group trial will include 56 patients who had undergone primary THA. Patients are randomized to a control group (standard rehabilitation during the 2-week stay in the rehabilitation clinic followed by 3 weeks of unsupervised home-based rehabilitation) or an experimental group (standard rehabilitation during the 2-week stay in the rehabilitation clinic followed by 3 weeks of home-based ReHub-assisted telerehabilitation). The primary outcome is physical performance assessed through the Timed Up-and-Go (TUG) test. Secondary outcomes include independence level, pain intensity, hip disability, hip range of motion, muscle strength, and patient's perception of clinical improvement. DISCUSSION: Proving the clinical and cost-effectiveness of a home-based telerehabilitation program for physical and muscle function following THA could support its systematic incorporation in post-surgical rehabilitation protocols, which should be tailored to the individual and collective needs. TRIAL REGISTRATION: ClinicalTrial.gov NCT04176315 . Registered on 22 November 2019.

Algo-Functional Indexes and Spatiotemporal Parameters of Gait after Sacroiliac Joint Arthrodesis.

Aims of the study were to evaluate the reliability and validity of the Italian version of the Majeed and Iowa questionnaires and to investigate the long-term surgical outcomes following sacroiliac joint arthrodesis. Twenty one patients who underwent a sacroiliac joint arthrodesis and 21 healthy subjects were evaluated. The experimental procedure consisted of gait analysis and a physical activity assessment (in both groups) and of administration of outcome questionnaires and pain assessment (in the patient group). The Majeed and Iowa questionnaires showed excellent reliability, excellent (for the Majeed questionnaire) and good (for the Iowa questionnaire) construct validity, and poor convergent validity (for both questionnaires) relative to walking speed. Most of the patients reported no pain and minimum pain-related disability and their physical activity profile was comparable to healthy controls. Patients showed an impaired walking performance (i.e., they walked slower and using shorter steps) compared with healthy controls. Long-term walking pattern abnormalities following sacroiliac joint arthrodesis may occur despite excellent clinical results. Given their excellent reliability and construct validity, the Majeed and Iowa questionnaires can be used in combination with the assessment of spatiotemporal gait parameters for the prognostic assessment and/or follow-up of surgical patients.

Rectus Femoris Characteristics in Post Stroke Spasticity: Clinical Implications from Ultrasonographic Evaluation.

In stroke survivors, rectus femoris (RF) spasticity is often implicated in gait pattern alterations such as stiff knee gait (SKG). Botulinum toxin type A (BoNT-A) is considered the gold standard for focal spasticity treatment. However-even if the accuracy of injection is crucial for BoNT-A efficacy-instrumented guidance for BoNT-A injection is not routinely applied in clinical settings. In order to investigate the possible implications of an inadequate BoNT-A injection on patients' clinical outcome, we evaluated the ultrasound-derived RF characteristics (muscle depth, muscle thickness, cross-sectional area and mean echo intensity) in 47 stroke survivors. In our sample, we observed wide variability of RF depth in both hemiparetic and unaffected side of included patients (0.44 and 3.54 cm and between 0.25 and 3.16 cm, respectively). Moreover, our analysis did not show significant differences between treated and non-treated RF in stroke survivors. These results suggest that considering the inter-individual variability in RF muscle depth and thickness, injection guidance should be considered for BoNT-A treatment in order to optimize the clinical outcome of treated patients. In particular, ultrasound guidance may help the clinicians in the long-term follow-up of muscle quality.

Common Musculoskeletal Disorders in the Elderly: The Star Triad.

Musculoskeletal disorders are debilitating conditions that significantly impair the state of health, especially in elderly subjects. A pathological triad of inter-related disorders that are highly prevalent in the elderly consists of the following main "components": sarcopenia, tendinopathies, and arthritis. The aim of this review is to critically appraise the literature relative to the different disorders of this triad, in order to highlight the pathophysiological common denominator and propose strategies for personalized clinical management of patients presenting with this combination of musculoskeletal disorders. Their pathophysiological common denominator is represented by progressive loss of (focal or generalized) neuromuscular performance with a risk of adverse outcomes such as pain, mobility disorders, increased risk of falls and fractures, and impaired ability or disability to perform activities of daily living. The precise management of these disorders requires not only the use of available tools and recently proposed operational definitions, but also the development of new tools and approaches for prediction, diagnosis, monitoring, and prognosis of the three disorders and their combination.

Long-term effects of intra-articular oxygen-ozone therapy versus hyaluronic acid in older people affected by knee osteoarthritis: A randomized single-blind extension study.

BACKGROUND: There is little evidence on intra-articular (IA) treatment in knee osteoarthritis (KOA) and there is a lack of long-term follow-up studies. OBJECTIVE: To assess the long-term effectiveness and safety of IA oxygen-ozone (O2O3) and hyaluronic acid (HA) in terms of functioning in KOA patients over a 31-week period. METHODS: Patients aged ⩾ 60 years with KOA were randomly allocated to receive 4 IA knee injections (1/week) of O2O3 or HA (T0-T3) and a follow-up visit 4 weeks after the fourth injection (T4). In this extension study we assessed VAS and safety in patients with Visual Analogue Scale (VAS) ⩾ 4 at the at 6-month follow-up visit (T5), undergoing a second treatment cycle (T5-T8) and 1-month follow-up visit (T9). RESULTS: Forty-two patients (aged 70.5 ± 5.8 years) were randomly allocated to O2O3 (n= 22) or HA group (n= 20). Twenty-three underwent another IA cycle: 12 (54.6%) in the O2O3 group and 11 (55.0%) in the HA group. Both groups showed significant reduction in VAS (p< 0.013) compared to baseline during both cycles. At follow-up visits (T4 and T9), VAS was significantly lower in the HA group (p< 0.013). There were no differences in adverse events occurrence between groups. CONCLUSIONS: IA O2O3 might be comparable to HA in terms of effectiveness and safety in reducing pain in KOA patients, although at both follow-up visits (T4 and T9) VAS was significantly lower in the HA group.

Return to Competition After Surgery for Herniated Lumbar Disc in Professional Football Players.

OBJECTIVE: To investigate the prevalence and outcomes of surgery for lumbar disc herniation in professional football players. DESIGN: Retrospective case series. SETTING: Sports rehabilitation center. PARTICIPANTS: A period of 10 seasons of the Italian Football First League (Serie A) was retrospectively investigated. Thirty-three teams (for a total of 1960 players) took turns in the 10 seasons, and 42 team doctors were requested to provide information about the number of players who underwent surgery for lumbar disc herniation. INTERVENTION: Survey distributed to team doctors. MAIN OUTCOME MEASURES: Prevalence and match incidence of the lumbar discectomy, proportion of players returning to competition after surgery, recovery time and preintervention and postintervention number of appearances in official matches were analyzed. RESULTS: Eleven players underwent the surgical intervention during the considered period. The prevalence of the surgical treatment was 0.6%, whereas the match incidence was 0.09 cases/1000 match hours. All players returned to competitions 6.0 (3.5-7.7) months after surgery, with no significant difference between different roles. The number of appearances in official matches was comparable during the seasons before and after surgery. CONCLUSIONS: The lumbar discectomy must be considered a rare surgical procedure performed in professional football players. All players returned to competitions after surgery. The postintervention number of appearances in official matches was comparable with the preintervention one.

Low back pain related to a sacral insufficiency fracture: role of paravertebral oxygen-ozone therapy in a paradigmatic case of nociplastic pain.

We describe the case of a 68-year-old woman with an acute episode of severe low back pain (LBP) resistant to opioids, who had experienced a sacral insufficiency fracture (SIF) two years earlier. At clinical examination, patient reported constant, dull, non-localizable pain at lumbar and sacral level, exacerbated by paravertebral palpation, particularly at L4-L5 and the sacroiliac joint, with a concomitant and remittent neuropathic component, difficult to localize at lumbar and sacral level. The latest magnetic resonance imaging study revealed disc herniations at L3-L4, L4-L5, and L5-S1 levels. The patient was treated with intramuscularparavertebral injections of oxygen-ozone (O2O3) mixture for 4 weeks (once a week), using a O3 concentration of 20 mcg/mL (5 mL in L4-L5 zone and 5 mL in L5-S1 zone, bilaterally). At 1 week after the first injection, the pain (assessed by Numerical Pain Rating Scale and Brief Pain Inventory) was considerably reduced and the patient's health-related quality of life (assessed by Short Form 12-Item Health Survey and European Quality of Life Index) had improved; these findings were confirmed at follow-up 1 month after the last injection. This paradigmatic case of nociplastic pain successfully treated by paravertebral O2O3 therapy might be a starting point for further studies on the effects of this treatment in terms of decreasing pain and improving HRQoL in patients affected by opioid-resistant LBP.

Transverse Muscle Ultrasound Analysis (TRAMA): Robust and Accurate Segmentation of Muscle Cross-Sectional Area.

Ultrasonography allows non-invasive and real time-measurement of the visible cross-sectional area (CSA) of muscles, which is a clinically relevant descriptor of muscle size. The aim of this study was to develop and validate a fully automatic method called transverse muscle ultrasound analysis (TRAMA) for segmentation of the muscle in B-mode transverse ultrasound images and measurement of muscle CSA. TRAMA was tested on a database of 200 ultrasound images of the rectus femoris, vastus lateralis, tibialis anterior and medial gastrocnemius muscles. The automatic CSA measurements were compared with manual measurements obtained by two operators. There were no statistical differences between the automatic and manual measurements of CSA of the four muscles, and TRAMA performance was comparable to intra-operator variability in terms of the Dice similarity coefficient and Hausdorff distance between the automatic and manual segmentations. Compared with manual segmentation, the Dice similarity coefficient for the proposed method was always higher than 93%; the Hausdorff distance never exceeded 4 mm, and the maximum absolute error was 62 mm2. TRAMA is the first automated algorithm that analyzes and segments ultrasound scans of the muscle in the transverse plane. It can be adopted in future studies for automatic segmentation of muscle regions of interest to enhance and automatize a multitexture analysis of muscle structure.

Diagnostic evaluation in steroid-induced myopathy: case report suggesting clinical utility of quantitative muscle ultrasonography.

PURPOSE: We present a patient with adrenal Cushing's syndrome causing steroid myopathy. The purpose of the case report is to illustrate the clinical usefulness of quantitative muscle ultrasonography for the assessment of glucocorticoid-induced changes in muscle mass (MM) and structure. METHODS: Assessments of physical performance, muscle strength, MM (i.e., total body skeletal MM, appendicular skeletal MM, and thickness of lower limb muscles), and muscle structure (i.e., echo intensity of lower limb muscles) were performed in the patient both in the active phase of the disease (preoperatively) and 6 months after surgical intervention (postoperatively). RESULTS: Muscle strength, physical performance, and MM were low both preoperatively and postoperatively. We also found preoperatively an increased echo intensity that normalized postoperatively. CONCLUSIONS: Clinical implications of these findings are double-fold. First, although the muscle structure can recover quickly in steroid myopathy patients, the recovery of MM may take months to years. Second, we show that muscle echo intensity can be useful to track the progression of steroid myopathy overtime and may help to indicate early response to therapeutic interventions. Further prospective studies are needed to confirm the value of muscle echo intensity in patients with endogenous or exogenous Cushing's syndrome presenting with steroid myopathy.

A systematic literature review of reviews on techniques for physical activity measurement in adults: a DEDIPAC study.

The links between increased participation in Physical Activity (PA) and improvements in health are well established. As this body of evidence has grown, so too has the search for measures of PA with high levels of methodological effectiveness (i.e. validity, reliability and responsiveness to change). The aim of this "review of reviews" was to provide a comprehensive overview of the methodological effectiveness of currently employed measures of PA, to aid researchers in their selection of an appropriate tool. A total of 63 review articles were included in this review, and the original articles cited by these reviews were included in order to extract detailed information on methodological effectiveness.Self-report measures of PA have been most frequently examined for methodological effectiveness, with highly variable findings identified across a broad range of behaviours. The evidence-base for the methodological effectiveness of objective monitors, particularly accelerometers/activity monitors, is increasing, with lower levels of variability observed for validity and reliability when compared to subjective measures. Unfortunately, responsiveness to change across all measures and behaviours remains under-researched, with limited information available.Other criteria beyond methodological effectiveness often influence tool selection, including cost and feasibility. However, researchers must be aware of the methodological effectiveness of any measure selected for use when examining PA. Although no "perfect" tool for the examination of PA in adults exists, it is suggested that researchers aim to incorporate appropriate objective measures, specific to the behaviours of interests, when examining PA in free-living environments.

Effects of vitamin D on insulin resistance and myosteatosis in diet-induced obese mice.

Epidemiological studies pointed out to a strong association between vitamin D deficiency and type 2 diabetes prevalence. However, the role of vitamin D supplementation in the skeletal muscle, a tissue that play a crucial role in the maintenance of glucose homeostasis, has been scarcely investigated so far. On this basis, this study aimed to evaluate the effect of vitamin D supplementation in a murine model of diet-induced insulin resistance with particular attention to the effects evoked on the skeletal muscle. Male C57BL/6J mice (n = 40) were fed with a control or a High Fat-High Sugar (HFHS) diet for 4 months. Subsets of animals were treated for 2 months with vitamin D (7 µg·kg-1, i.p. three times/week). HFHS diet induced body weight increase, hyperglycemia and impaired glucose tolerance. HFHS animals showed an impaired insulin signaling and a marked fat accumulation in the skeletal muscle. Vitamin D reduced body weight and improved systemic glucose tolerance. In addition, vitamin D restored the impaired muscle insulin signaling and reverted myosteatosis evoked by the diet. These effects were associated to decreased activation of NF-κB and lower levels of TNF-alpha. Consistently, a significantly decreased activation of the SCAP/SREBP lipogenic pathway and lower levels of CML protein adducts and RAGE expression were observed in skeletal muscle of animals treated with vitamin D. Collectively, these data indicate that vitamin D-induced selective inhibition of signaling pathways (including NF-κB, SCAP/SREBP and CML/RAGE cascades) within the skeletal muscle significantly contributed to the beneficial effects of vitamin D supplementation against diet-induced metabolic derangements.

Diagnostic work-up in steroid myopathy.

INTRODUCTION: Steroid myopathy is a well-known sign of endogenous Cushing's syndrome as well as a side effect of glucocorticoid administration. The clinical finding of muscle weakness and the clinical inspection of the muscle size are the most commonly used diagnostic tools, sometimes in combination with needle electromyography, but there are no means to detect the myopathy before the appearance of clinical or electrodiagnostic signs. Until now, no guidelines have been produced for a disease-specific evaluation of muscle impairment in patients with Cushing's syndrome. REVIEW: We reviewed the measurement properties and limitations of the following tools that are currently adopted in clinical research and routine care for diagnosis and monitoring of steroid myopathy: muscle strength assessment; needle biopsy; intramuscular and surface electromyography; laboratory assays; muscle mass assessments (through bioelectrical impedance analysis, dual-energy X-ray absorptiometry, and computed tomography). CONCLUSIONS: We suggest that the management of steroid myopathy patients in clinical research and practice would benefit from a multidisciplinary approach based on the combined assessment of muscle mass, strength, and performance. However, further studies are required to establish an operational definition of steroid myopathy and to identify population-specific criteria for diagnosis of the myopathic process.

Higher protein intake is associated with improved muscle strength in elite senior athletes.

OBJECTIVE: The optimal protein intake for elderly individuals who exercise regularly has not yet been clearly defined. The aim of this study was to test the hypothesis that protein intake level is associated with muscle strength in elderly elite athletes. METHODS: We evaluated 50 elite senior athletes (38 men and 12 women) participating in the European Master Games 2011 in an observational cross-sectional study. Participants were divided into two groups-lower (LPI) or higher (HPI) protein intake-according to the median value of their ratio of urinary urea nitrogen to urinary creatinine (i.e., 8.8 g/L), as a marker of protein intake. A dietary interview confirmed differences in protein consumption between the LPI and HPI groups. We also evaluated body composition (bioimpedance), muscle strength, and hematochemical indices. RESULTS: LPI and HPI groups were homogeneous for age (72 [68-74] and 71 [68-74] y, respectively), fat-free mass index (18.4 [17-19.4] and 18.2 [17-19.1] kg/m2), body fat (18.3% [12.3-20.7%] and 16.6% [13.6-21.2%]), and glomerular filtration rate (57.7 [53.8-64.9] and 62.7 [56.1-69.3] mL/min/1.73 m2). The HPI group showed greater leg and trunk muscle strength (N) compared with the LPI group (left leg extension, 339 [238-369] versus 454 [273-561], respectively, P < 0.05; right leg extension, 319 [249-417] versus 432 [334-635], P ≤ 0.05; trunk extension, 435 [370-467] versus 464 [390-568], P ≤ 0.05). CONCLUSIONS: Higher protein intake in elite senior athletes is associated with a greater muscle strength.

Quantitative analysis of patellar tendon size and structure in asymptomatic professional players: sonographic study.

BACKGROUND: Ultrasonographic abnormalities of the patellar tendon frequently occur in asymptomatic athletes and it is not always clear whether they precede (and may predict) the development of tendinopathy. OBJECTIVE: This study aimed to investigate by ultrasonography the prevalence of patellar tendon abnormalities in players of "pallapugno" and to establish whether structural tendon abnormalities predict tendinopathy development. METHODS: Ultrasound B-mode images of the patellar tendon of both sides were acquired in fourteen throwers. Qualitative assessments of tendon structure and neovascularization and quantitative assessments of tendon thickness, cross sectional area (CSA), and echo-intensity were performed. RESULTS: Qualitative assessments showed a subclinical tendinopathy of the non-dominant tendon in 5 out of 14 throwers (35% of cases), while quantitative assessments showed abnormalities of the non-dominant tendon in 8 out of 14 players (57% of cases). Echo-intensity and CSA were the quantitative variables most discriminant between asymptomatic players without structural tendon abnormalities and those with tendon abnormalities. Two players (2 out of 8 cases: 25%) developed a clinical tendinopathy after a follow-up of six months. CONCLUSION: The prevalence of subclinical tendinopathy in the non-dominant patellar tendon of throwers was high. Patellar tendon abnormalities at baseline seem to increase the risk of development of subsequent patellar tendinopathy. LEVEL OF EVIDENCE: II b (individual cohort study).

Fully Automated Muscle Ultrasound Analysis (MUSA): Robust and Accurate Muscle Thickness Measurement.

Musculoskeletal ultrasound imaging allows non-invasive measurement of skeletal muscle thickness. Current techniques generally suffer from manual operator dependency, while all the computer-aided approaches are limited to be semi-automatic or specifically optimized for a single muscle. The aim of this study was to develop and validate a fully automatic method, named MUSA (Muscle UltraSound Analysis), for measurement of muscle thickness on longitudinal ultrasound images acquired from different skeletal muscles. The MUSA algorithm was tested on a database of 200 B-mode ultrasound images of rectus femoris, vastus lateralis, tibialis anterior and medial gastrocnemius. The automatic muscle thickness measurements were compared to the manual measurements obtained by three operators. The MUSA algorithm achieved a 100% segmentation success rate, with mean differences between the automatic and manual measurements in the range of 0.06-0.45 mm. MUSA performance was statistically equal to the operators and its measurement accuracy was independent of the muscle thickness value.