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Purpose: This study aimed to investigate the changes of the posterior paraspinal muscles (PPM) and psoas muscle in patients with low back pain (LBP) over time. Methods: Patients with LBP who had a repeat lumbar MRI with a minimum of 3-years apart at a tertiary referral center were analyzed. MRI-based quantitative assessments of the PPM and the psoas muscle were conducted for the baseline and follow-up MRI. The cross sectional area (CSA), the functional cross sectional area (fCSA) and the fat area (FAT) were calculated using a dedicated software program. The fatty infiltration (FI,%) of the regions of interest was calculated. Differences between the 1st and 2nd MRI were calculated for all assessed muscular parameters. Results: A total of 353 patients (54.4%female) with a median age of 60.1 years and BMI of 25.8 kg/m2 at baseline were analyzed. The mean time between the 1st and 2nd MRI was 3.6 years. The fCSAPPM declined in both sexes significantly from the 1st to the 2nd MRI, whereas the FATPPM increased. In line with this result, the FIPPM increased in both males (29.9%) and females (19.4%). Females had a higher FIPPM and FIPsoas than males in both MRIs. In females, no significant changes were found for the psoas muscle. The CSAPsoas and fCSAPsoas in males were significantly smaller in the 2nd MRI. With increasing age, a significant trend in a decrease in ∆FIPPM was observed for both sexes. Conclusion: The study revealed significant quantitatively muscular changes in males and females, especially in the posterior paraspinal muscles in only three years' time. [ABSTRACT FROM AUTHOR]

Background: Muscle quantification is an essential step in sarcopenia evaluation. Purpose: To develop and evaluate an automated machine learning (ML) algorithm for segmenting the paraspinous muscles on either abdominal or lumbar (L) computed tomography (CT) scans. Material and Methods: A novel deep neural network algorithm for automated segmentation of paraspinous muscle was developed, CT scans of 504 consecutive patients conducted between January 2019 and February 2020 were assembled. The muscle was manually segmented at L3 vertebra level by three radiologists as ground truth, divided into training and testing subgroups. Muscle cross-sectional area (CSA) was recorded. Dice similarity coefficients (DSCs) and CSA errors were calculated to evaluate system performance. The degree of muscle fat infiltration (MFI) recording by percentage value was the fat area within the region of interest divided by the muscle area. An analysis of the factors influencing the performance of the V-net-based segmentation system was also implemented. Results: The mean DSCs for paraspinous muscles were high for both the training (0.963, 0.970, 0.941, and 0.968, respectively) and testing (0.950, 0.960, 0.929, and 0.961, respectively) datasets, while the CSA errors were low for both training (1.9%, 1.6%, 3.1%, and 1.3%, respectively) and testing (3.4%, 3.0%, 4.6%, and 1.9%, respectively) datasets. MFI and muscle area index (MI) were major factors affecting DSCs of the posterior paraspinous and paraspinous muscle groups. Conclusion: The ML algorithm for the measurement of paraspinous muscles was compared favorably to manual ground truth measurements. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to determine if epaxial muscle height (EMH) could be reliably incorporated into annual routine wellness screenings, and also determine its relationship to age, body condition score (BCS), subjective muscle assessment (SMA), breed and sex in mature cats. Methods: EMH was determined independently by three observers from ultrasonographic examinations – collected by an additional trained individual – of cats enrolled at the Feline Healthy Ageing Clinic, University of Liverpool, UK. Age, body weight, BCS and SMA data were also collected. Results: A total of 92 cats were included, 35 of which had repeat ultrasonographic examinations 12 months apart. Enrolled cats were a median age of 8 years and 9 months at the time of the first measurement. Variation in the quality of ultrasonographic images collected did not affect muscle depth measurements (P = 0.974). Further, there was good intra- and inter-observer repeatability for all observations (intraclass correlation range 0.97−0.99). There was a moderate positive association between EMH and body weight (r = 0.49, P <0.001) but no association with age (r = −0.05, P = 0.680). There were also positive associations in EMH among cats with different BCSs (P = 0.001) and SMAs (thoracic spine, P = 0.021; lumbar spine, P = 0.014), but breed (P = 0.429) and sex (P = 0.187) had no effect. Finally, there was no change in EMH measurements in the paired samples (P = 0.145) or correlation between percentage weight and EMH change over 12 months. Conclusions and relevance: The accuracy of EMH measurement using ultrasonographic imaging is good, irrespective of observer experience and provided that the ultrasonographer has some training. This suggests that ultrasonographic measurement of EMH could have a major practical impact as a non-invasive determination of muscle mass in pet cat populations. Further research is required to assess longitudinal changes in muscle mass over time in senior pet cats. [ABSTRACT FROM AUTHOR]

Background: Skeletal muscle depletion is common in old adults and individuals with chronic comorbidities, who have an increased risk of developing severe coronavirus disease 2019 (COVID-19), which is defined by hypoxia requiring supplemental oxygen. This study aimed to determine the association between skeletal muscle depletion and clinical outcomes in patients with severe COVID-19.Methods: One hundred and sixteen patients with severe COVID-19 who underwent chest computed tomography scan on admission were included in this multicenter, retrospective study. Paraspinal muscle index (PMI) and radiodensity (PMD) were measured using computed tomography images. The primary composite outcome was the occurrence of critical illness (respiratory failure requiring mechanical ventilation, shock, or intensive care unit admission) or death, and the secondary outcomes were the duration of viral shedding and pulmonary fibrosis in the early rehabilitation phase. Logistic regression and Cox proportional hazards models were employed to evaluate the associations.Results: The primary composite outcome occurred in 48 (41.4%) patients, who were older and had lower PMD (both p < .05). Higher PMD was associated with reduced risk of critical illness or death in a fully adjusted model overall (odds ratio [OR] per standard deviation [SD] increment: 0.87, 95% confidence interval [CI]: 0.80-0.95; p = .002) and in female patients (OR per SD increment: 0.71, 95% CI: 0.56-0.91; p = .006), although the effect was not statistically significant in male patients (p = .202). Higher PMD (hazard ratio [HR] per SD increment: 1.08, 95% CI: 1.02-1.14; p = .008) was associated with shorter duration of viral shedding among female survivors. However, no significant association was found between PMD and pulmonary fibrosis in the early rehabilitation phase, or between PMI and any outcome in both men and women.Conclusions: Higher PMD, a proxy measure of lower muscle fat deposition, was associated with a reduced risk of disease deterioration and decreased likelihood of prolonged viral shedding among female patients with severe COVID-19. [ABSTRACT FROM AUTHOR]

Purpose: Although changes in lateral abdominal wall musculature after posterior component separation with transversus abdominis release have been investigated, the effects of endoscopic subcutaneous anterior component separation (ES-ACS) on postoperative muscle anatomy have not been evaluated. The purpose of this study was to evaluate changes in the lateral abdominal muscles after ES-ACS. Methods: Computed tomography (CT) images of patients who underwent ES-ACS were retrospectively evaluated. Lateral abdominal wall thickness and external oblique displacement were measured at the level of fixed retroperitoneal structures. Measurements on the ES-ACS side were compared with those on the contralateral undivided side or with preoperative images in patients with bilateral procedures. Results: Fifteen patients met the criteria for study inclusion. Most patients (n = 13, 86.7%) underwent unilateral ES-ACS. The most commonly performed procedure was laparoscopic intraperitoneal onlay mesh-plus hernia repair (n = 12, 80.0%; the remaining patients underwent open repair). The Mean defect width was 8.4 cm (range 6–15 cm). There was no difference in the thickness of the lateral abdominal musculature between ES-ACS and undivided sides. There was a significant lateral displacement of the external oblique muscle from the lateral edge of the rectus abdominis on the ES-ACS side (mean distance 3.7 cm; p = 0.0006). No midline hernia recurrences, iatrogenic linea semilunaris hernias, or lateral eventrations were observed during a mean follow-up period of 2.6 years (range 0.5–7.4 years). Conclusion: ES-ACS resulted in no atrophy of the lateral abdominal muscles in long-term CT follow-up. The procedure is a safe and effective adjunct to complex hernia repair in selected patients. [ABSTRACT FROM AUTHOR]

Background/Aim: Muscle loss, inflammation, and frailty are prevalent among older cancer patients. We aimed to evaluate whether inflammatory markers could identify muscle loss, and if muscle measures differed between frail and non-frail patients. Patients and Methods: A total of 115 patients ≥70 years old with solid tumors were included. Inflammation was measured using the Glasgow Prognostic Score (GPS), which is based on C-reactive protein (CRP) and albumin levels, and CRP alone. Frailty was evaluated using a modified geriatric assessment (mGA) of eight domains affecting older patients’ health status. Computed tomography-derived muscle measures were collected at the level of the third lumbar vertebra. Results: Patients with GPS=2 and CRP>27 mg/l exhibited poorer muscle measures compared to patients with lower levels. No associations between mGA-based frailty and muscle mass were found. Conclusion: Inflammation has detrimental effects on muscle. [ABSTRACT FROM AUTHOR]

Abstract Achilles tendon ruptures are common injuries that often lead to long-term functional deficits. Despite the prevalence of these injuries, the mechanism responsible for limited function has not yet been established. Therefore, the purpose of this study was to present preliminary findings that support a hypothesis that skeletal muscle remodeling is the driving factor of poor outcomes in some patients. Biomechanical and ultrasonography assessments were performed on a patient that presented with poor functional outcomes 2.5 years after a surgically-repaired acute Achilles tendon rupture. Single-leg heel raise height was decreased by 75% in the affected limb (3.0 cm compared to 11.9 cm) while walking mechanics showed no deficits. Ultrasonography revealed that the affected medial gastrocnemius muscle was less thick and had shorter, more pennate fascicles compared to the unaffected limb. A simple computational model of a maximal-effort plantarflexion contraction was employed to test the implications of changes in muscle architecture on single-leg heel raise function. Subject-specific measurements of fascicle length and pennation were input into the model, which supported these architectural parameters as being drivers of heel raise function. These preliminary findings support the hypothesis that an Achilles tendon rupture elicits changes in skeletal muscle architecture, which reduces the amount of work and power the joint can generate. This multidisciplinary framework of biomechanical, imaging, and computational modeling provides a unique platform for studying the complex interactions between structure and function in patients recovering from Achilles tendon injuries. [ABSTRACT FROM AUTHOR]

The purpose of the study was to compare smart apparel (SA) muscle activity measurements to surface electromyography (sEMG) muscle activity measurements during exercise, and determine if any systematic bias of the apparel exists. Thirty-five male participants (Ages 23.1±2.92 yrs, height 178±0.09 cm, mass 81.14±10.59 kg, body fat percentage 15.4±4.79%) provided informed consent for participation. During two separate exercise sessions, participants performed three sets of 12 bodyweight squats and pushups in both SA and sEMG. Conditions (sEMG or SA) were randomly counterbalanced. During sEMG, sensors were placed at selected anatomical locations on the right side. During SA, sEMG sensors were sewn into the fabric. Percent of maximal voluntary contractions (%MVC) were calculated. Paired t-test were used to analyze group mean differences in %MVC between conditions. Bland & Altman plots were created to determine any systematic bias. A Pearson's product correlation was run to determine any association with intertrial variability and body fat percentage. The alpha levels were set a p<0.05. It was determined that there were no significant differences between %MVC in the SA and sEMG for three of the selected muscles (p>0.05). There was a significant difference in %MVC measured in the SA and sEMG for the RDELT (p=0.02). Specifically, the %MVC for the deltoid during pushups was 11.8% greater compared to sEMG. Intertrial differences were not significantly correlated with %BF (p>0.05). The apparel appears to be valid in the recreational population and appears to have no systematic bias. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to clarify the reference values of muscle thicknesses by age and to elucidate the association of muscle thickness with physical function in a large group of community-dwelling elderly individuals.Participants and methods: The muscle thicknesses of the rectus femoris (RF), vastus intermedius (VI), and quadriceps femoris (QF) in 777 of 831 enrolled elderly individuals were measured by ultrasonography, and physical function was measured using knee extension strength (KES), one-legged stance, walking, Timed Up and Go, and grip strength tests. Muscle thickness data were divided by sex and categorized into 5-year age groups. Differences in muscle thickness and KES among the age groups were examined, and correlations between muscle thickness and physical function test results were compared by age. The non-parametric independent two-sample Mann–Whitney U-test, Kruskal-Wallis test, and Spearman's correlation coefficients were used in the statistical analysis.Results: Thickness of the RF showed fewer significant differences among all groups and less decreases compared to thickness of the VI in older age groups, especially in men. Thicknesses of the RF, VI, and QF correlated with KES in almost all the thicknesses of muscles in the 65–69 and 70–74 years age groups in men and in almost all age groups in women. The decrease in muscle thicknesses and degree of correlations with aging were different between men and women.Conclusions: Reductions in the thicknesses of the muscles and KES differed by age group and sex. Our results could be used for prescribing exercise in community-dwelling elderly individuals of varying ages. [ABSTRACT FROM AUTHOR]

Summary: Previous studies have investigated the relationship between ultrasound‐measured muscle thickness (MT) and individual muscle cross‐sectional area (CSA); however, the forearm muscle had not yet been studied. The purpose of this study was to examine the relationship between forearm MT by ultrasound and the muscle CSA of the forearm obtained by magnetic resonance imaging (MRI). Ten young and middle‐aged adults had both ultrasound and MRI measurements at 30% the distance from the styloid process of the ulna to the head of the radius. Handgrip strength (HGS) was also measured. Strong correlations (P<0·001) were observed between MRI‐measured muscle CSA (total and flexor and extensor components) and MT‐ulna (ranged r = 0·937–0·946) and MT‐radius (ranged r = 0·884–0·891). HGS was also correlated (P<0·001) with forearm MT (MT‐ulna, r = 0·877; MT‐radius, r = 0·852) and MRI‐measured muscle CSA (flexor CSA, r = 0·910; extensor CSA, r = 0·923). Our results suggest that forearm MT is closely associated with MRI‐measured forearm muscle CSA in young and middle‐aged adults and suggest that ultrasound‐measured forearm muscle thickness may be a useful variable for evaluating muscle CSA and function in the forearm. [ABSTRACT FROM AUTHOR]

Intramuscular injections given at the dorsogluteal and ventrogluteal sites are intended for the gluteus maximus and gluteus medius muscles, respectively. However, little research has confirmed the reliability of these sites for the presence and thickness of the target and other muscles, and subcutaneous fat. This study characterised and compared these at the V-method and G-method ventrogluteal sites and dorsogluteal site (n=60). Gluteus maximus, medius and minimus were identified at each site, plus tensor fascia latae at ventrogluteal sites. Gluteus maximus and subcutaneous fat were significantly thicker and gluteus minimus significantly thinner at the dorsogluteal site than both ventrogluteal sites. Gluteus medius was the thickest muscle at each injection site, and thicker at the G-method than the V-method ventrogluteal site. Therefore, the dorsogluteal site reliably targets gluteus maximus, and the G-method ventrogluteal site was more reliable than the V-method ventrogluteal site to target gluteus medius in terms of presence and thickness. [ABSTRACT FROM AUTHOR]

Asymmetry of body parts refers to absence of symmetry and unevenly developed body parts in terms of the axis and plane. It has been long ago noticed that no perfectly correct human body exists, and bodies are to a greater or lesser extent asymmetric. A passive way of life, insufficient movement and inappropriate ergonomics of the workplace have a negative impact on the skeletal muscle system, usually resulting in reduced muscle power, static and dynamic muscle endurance, and altered muscle tone. The aim is to determine whether muscle myotonometry parameters are informative in early risk diagnostics to predict the likelihood of skeletal muscle system trauma. The study involved 382 people aged 18-24. Participants were devided into two groups: according to the accumulated composite score. Testing was made one time. The study consisted of functional movement and myotonometry evaluation. The study analyses and presents comparisons of the results depending on the trauma likelihood and sex. In addition, asymmetry of the left and the right body side is investigated. The analysis of the asymmetries (delta) in the frequency of damped oscillations of trapezius, biceps femoris, gastrocnemius (inner and outer part) on the left and right sides of the body demonstrated greater asymmetries between the left and the right sides of the body in the groups of both men and women with a lower chance of trauma. The assessment of asymmetries in femoris rectus and tibialis anterior between the left and the right sides of the body showed differences in the frequency of damped oscillations in all groups. Muscle myotonometry parameters are informative and may be used in early risk diagnostics to predict skeletal muscle system trauma. The asymmetry in tibialis muscle tone between the left and the right leg causes poorer parameters of functional movement performance in women. No associations were found to exist with the ability to perform functional movements in men. The asymmetry in femoris muscle tone between the left and right leg demonstrates the ability of young subjects to perform functional movements. It is characteristic of men and, to a lower extent, of women. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the intra- and inter-reliability and the ease of measuring the quadriceps muscle thickness using bedside ultrasound. Methods: This is a prospective, observational study. The assessment of quadriceps muscle thickness was performed at two reference points and was quantified using portable B-mode ultrasound in two healthy volunteers. For standardization of measurements and validation of image collections, the team was trained through theoretical and practical classes, with a 6-hour workload. Results: A total of 112 images were examined by the coach and compared with the trainees. Pearson's correlation analysis found an excellent relationship between the coach and all trainees (R² > 0.90). The best association was between the coach and the dietitians (R²: 0.99; p < 0.001), and the worst association was between the coach and the medical trainees (R²: 0.92; p < 0.001). In the Bland-Altman comparison, the highest error rate found between coach and trainees was 5.12% (95% confidence interval [CI] 3.64-12.37), and the lowest was 1.01% (95%CI 0.72 - 2.58); the highest bias of the values described was -0.12 ± 0.19, and the lowest was -0.01 ± 0.04. Conclusion: The data analyzed showed a good correlation between the measurements made by the coach and trainees, indicating that ultrasound of the quadriceps muscle is a viable and easily applicable tool. [ABSTRACT FROM AUTHOR]

The purpose of the current studywas (1) to examine the differences between standing and lying measures of vastus lateralis (VL), muscle thickness (MT), pennation angle (PA), and cross-sectional area (CSA) using ultrasonography; and (2) to explore the relationships between lying and standing measures with isometric and dynamic assessments of force production-specifically peak force, rate of force development (RFD), impulse, and one-repetition maximum back squat. Fourteen resistance-trained subjects (age = 26.8 ± 4.0 years, height = 181.4 ± 6.0 cm, body mass = 89.8 ± 10.7 kg, back squat to body mass ratio = 1.84 ± 0.34) agreed to participate. Lying and standing ultrasonography images of the right VL were collected following 48 hours of rest. Isometric squat assessments followed ultrasonography, and were performed on force platforms with data used to determine isometric peak force (IPF), as well as RFD and impulse at various time points. Forty-eight hours later, one-repetition maximum back squats were performed by each subject. Paired-samples t-tests revealed statistically significant differences between standing and lying measurements of MT (p < 0.001), PA (p < 0.001), and CSA (p ≥ 0.05), with standing values larger in all cases. Further, standing measures were correlated more strongly and abundantly to isometric and dynamic performance. These results suggest that if practitioners intend to gain insight into strength-power potential based on ultrasonography measurements, performing the measurement collection with the athlete in a standing posture may be preferred. [ABSTRACT FROM AUTHOR]

Assessment of swallowing musculature using motor evoked potentials ( MEPs) can be used to evaluate neural pathways. However, recording of the swallowing musculature is often invasive, uncomfortable and unrealistic in normal clinical practice. To investigate the possibility of using the suprahyoid muscle complex ( SMC) using surface electromyography ( sEMG) to assess changes to neural pathways by determining the reliability of measurements in healthy participants over days. Seventeen healthy participants were recruited. Measurements were performed twice with one week between sessions. Single-pulse (at 120% and 140% of the resting motor threshold ( rMT)) and paired-pulse (2 ms and 15 ms paired pulse) transcranial magnetic stimulation ( TMS) were used to elicit MEPs in the SMC which were recorded using sEMG. ≈50% of participants (range: 42-58%; depending on stimulus type/intensity) had significantly different MEP values between day 1 and day 2 for single-pulse and paired-pulse TMS. A large stimulus artefact resulted in MEP responses that could not be assessed in four participants. The assessment of the SMC using sEMG following TMS was poorly reliable for ≈50% of participants. Although using sEMG to assess swallowing musculature function is easier to perform clinically and more comfortable to patients than invasive measures, as the measurement of muscle activity using TMS is unreliable, the use of sEMG for this muscle group is not recommended and requires further research and development. [ABSTRACT FROM AUTHOR]

Background Although the importance of sleep on preservation of several physiological functions is well known, the relationship with the two interconnected tissues - muscle and bone is less understood. Objectives This study aimed to examine the association of 24-hour sleep duration with mid-thigh muscle composition and proximal femur volumetric bone mineral density (vBMD). Methods 2438 men and 3326 women aged 66 to 96 years, residents in the Reykjavik area, were included in this cross-sectional study. Proximal femur integral vBMD, mid-thigh muscle area and muscle attenuation were assessed with computed tomography. Sleep and nap habits were assessed using a questionnaire. Results We found that after adjustment for age and BMI long sleep duration (> 8 h/d) was negatively associated with thigh lean area in both men (B = − 2.21, 95% confidence interval (CI): − 4.01, − 0.40) and women (B = − 2.39, 95% CI: − 3.75, − 1.03) and with muscle attenuation (B = − 0.95, 95% CI: − 1.47, − 0.43) only in women. After adjustments for age, health and lifestyle factors the association between long sleep duration and muscle lean area was attenuated and became nonsignificant while associations with muscle attenuation remained marginally significant (B = − 0.51, 95% CI: − 1.03, − 0.002). Sleep duration was not associated with proximal femur integral vBMD in the multivariate models. Conclusion Long sleep duration, particularly in old women, can affect thigh muscle attenuation (increase in intramuscular fat). Whether optimization of sleep can ameliorate age-associated intramuscular or intermuscular adipose tissue warrants further studies. [ABSTRACT FROM AUTHOR]

Purpose: The neurotomy of musculocutaneous nerve is a treatment for patients who suffer from spastic elbow flexion when medical and reeducative treatments have failed. It consists in sectioning motor branches of musculocutaneous nerve which are destined to the biceps brachii and brachialis muscles, both being the main elbow flexor muscles. The aim of this study was to analyse the distance, where each motor branch arises from the musculocutaneous nerve to both biceps brachii and brachialis muscles, to establish precisely the localisation and length of the necessary incision to reach its branches for surgery. Materials and methods: Eighteen musculocutaneous nerves from ten cadavers were dissected. None of them reported with a previous pathology. The cadavers were laid on the back with 30-35° of abduction, a complete extension, and supination of the upper limb. Results: The localization of motor branches was to be found in the middle third of the upper arm, with an average from the base of the humeral major tubercle of 11.46, 12.40, and 12.87 cm for the biceps brachii and 16.36, 19.10, and 16.88 cm for the brachialis muscle. Conclusion: The incision needed to reach the motor branches of the musculocutaneous nerve should be localised between 10 and 20 cm from the major humeral tubercle and may be shorter than usual. [ABSTRACT FROM AUTHOR]

Musculoskeletal injuries are a leading cause of disability in both the general population and military, and the ability to effectively quantify musculoskeletal function remains problematic. The aim of the current study is to investigate the reliability, responsiveness, and criterion validity of the kiio Sensor for measurement of muscle strength, a key aspect of comprehensive functional assessment. Forty-four (24 male, 20 female) physically active civilian adults (mean [SD] = 21.2 [1.5] years of age) with no history of upper extremity injuries in the last year and no current complaints of pain, weakness, or functional limitation completed two sessions of maximum shoulder external rotation contractions. The forces were measured with a kiio Sensor and isokinetic dynamometer. The devices showed strong correlation (r = 0.89) and no significant mean difference (0.3 ± 3.3 lb, p = 0.47). Intrasession reliability for both devices was analyzed using intraclass correlation coefficients (ICC3,1 = 0.96 [95% confidence interval = 0.93-0.98)], with the kiio Sensor having slightly less standard error and trial-to-trial variability. The kiio Sensor 7-day reliability was ICC3,3 = 0.97 (95% confidence interval = 0.94-0.98). The kiio Sensor demonstrates excellent reliability, responsiveness, and validity compared with a gold standard isokinetic dynamometer. Several key attributes contributing to this technology's military relevance are discussed. [ABSTRACT FROM AUTHOR]

Ultrasound imaging is often used to measure muscle fascicle lengths and pennation angles in human muscles in vivo. Theoretically the most accurate measurements are made when the transducer is oriented so that the image plane aligns with muscle fascicles and, for measurements of pennation, when the image plane also intersects the aponeuroses perpendicularly. However this orientation is difficult to achieve and usually there is some degree of misalignment. Here, we used simulated ultrasound images based on three-dimensional models of the human medial gastrocnemius, derived from magnetic resonance and diffusion tensor images, to describe the relationship between transducer orientation and measurement errors. With the transducer oriented perpendicular to the surface of the leg, the error in measurement of fascicle lengths was about 0.4 mm per degree of misalignment of the ultrasound image with the muscle fascicles. If the transducer is then tipped by 20°, the error increases to 1.1 mm per degree of misalignment. For a given degree of misalignment of muscle fascicles with the image plane, the smallest absolute error in fascicle length measurements occurs when the transducer is held perpendicular to the surface of the leg. Misalignment of the transducer with the fascicles may cause fascicle length measurements to be underestimated or overestimated. Contrary to widely held beliefs, it is shown that pennation angles are always overestimated if the image is not perpendicular to the aponeurosis, even when the image is perfectly aligned with the fascicles. An analytical explanation is provided for this finding. [ABSTRACT FROM AUTHOR]

Muscle fascicle lengths are commonly measured in vivo using static 2D ultrasound. However, static ultrasound is best suited for muscles with shorter, pennate fascicles, in which entire fascicles can be viewed in one static image. An informal review of data from cadaver dissections suggests that over 60% of muscles in the upper and lower limbs have optimal lengths longer than the field-of-view of standard ultrasound transducers. Extended field-of-view ultrasound (EFOV) has been validated for measurement of fascicle lengths, but has yet to be implemented in the upper extremity in humans. In this study, EFOV ultrasound was used to measure the lengths of fascicles sampled from the anterior portion of the biceps brachii (long head) and the distal half of the triceps brachii (lateral head). Data were collected from both limbs of eleven healthy subjects in three elbow postures under passive conditions. Image analysis was completed via Image J. Fascicle length measurements were highly reliable, with intra-class correlations ranging from .92 to .95 for biceps and .81–.92 for triceps ( p <.001). Systematic, significant differences in measured lengths, consistent with muscle function, were observed between elbow positions. In vivo measurements for both muscles in this study were within the range of cadaver data. This work establishes the feasibility and reliability of EFOV ultrasound for measurement of the long fascicles of muscles in the upper limb. [ABSTRACT FROM AUTHOR]

Sarcomere lengths have been a crucial outcome measure for understanding and explaining basic muscle properties and muscle function. Sarcomere lengths for a given muscle are typically measured at a single spot, often in the mid-belly of the muscle, and at a given muscle length. It is then assumed implicitly that the sarcomere length measured at this single spot represents the sarcomere lengths at other locations within the muscle, and force-length, force-velocity, and power-velocity properties of muscles are often implied based on these single sarcomere length measurements. Although, intuitively appealing, this assumption is yet to be supported by systematic evidence. The objective of this study was to measure sarcomere lengths at defined locations along and across an intact muscle, at different muscle lengths. Using second harmonic generation (SHG) imaging technique, sarcomere patterns in passive mouse tibialis anterior (TA) were imaged in a non-contact manner at five selected locations ("proximal," "distal," "middle," "medial," and "lateral" TA sites) and at three different lengths encompassing the anatomical range of motion of the TA. We showed that sarcomere lengths varied substantially within small regions of themuscle and also for different sites across the entire TA. Also, sarcomere elongations with muscle lengthening were non-uniform across the muscle, with the highest sarcomere stretches occurring near the myotendinous junction. We conclude that muscle mechanics derived from sarcomere length measured from a small region of a muscle may not well-represent the sarcomere length and associated functional properties of the entire muscle. [ABSTRACT FROM AUTHOR]

Background Dynamic measurements of human muscle fascicle length from sequences of B-mode ultrasound images have become increasingly prevalent in biomedical research. Manual digitisation of these images is time consuming and algorithms for automating the process have been developed. Here we present a freely available software implementation of a previously validated algorithm for semi-automated tracking of muscle fascicle length in dynamic ultrasound image recordings, “UltraTrack”. Methods UltraTrack implements an affine extension to an optic flow algorithm to track movement of the muscle fascicle end-points throughout dynamically recorded sequences of images. The underlying algorithm has been previously described and its reliability tested, but here we present the software implementation with features for: tracking multiple fascicles in multiple muscles simultaneously; correcting temporal drift in measurements; manually adjusting tracking results; saving and re-loading of tracking results and loading a range of file formats. Results Two example runs of the software are presented detailing the tracking of fascicles from several lower limb muscles during a squatting and walking activity. Conclusion We have presented a software implementation of a validated fascicle-tracking algorithm and made the source code and standalone versions freely available for download. [ABSTRACT FROM AUTHOR]

Objectives: Atlas-based segmentation is a powerful method for automatic structural segmentation of several sub-structures in many organs. However, such an approach has been very scarcely used in the context of muscle segmentation, and so far no study has assessed such a method for the automatic delineation of individual muscles of the quadriceps femoris (QF). In the present study, we have evaluated a fully automated multi-atlas method and a semi-automated single-atlas method for the segmentation and volume quantification of the four muscles of the QF and for the QF as a whole. Subjects and methods: The study was conducted in 32 young healthy males, using high-resolution magnetic resonance images (MRI) of the thigh. The multi-atlas-based segmentation method was conducted in 25 subjects. Different non-linear registration approaches based on free-form deformable (FFD) and symmetric diffeomorphic normalization algorithms (SyN) were assessed. Optimal parameters of two fusion methods, i.e., STAPLE and STEPS, were determined on the basis of the highest Dice similarity index (DSI) considering manual segmentation (MSeg) as the ground truth. Validation and reproducibility of this pipeline were determined using another MRI dataset recorded in seven healthy male subjects on the basis of additional metrics such as the muscle volume similarity values, intraclass coefficient, and coefficient of variation. Both non-linear registration methods (FFD and SyN) were also evaluated as part of a single-atlas strategy in order to assess longitudinal muscle volume measurements. The multi- and the single-atlas approaches were compared for the segmentation and the volume quantification of the four muscles of the QF and for the QF as a whole. Results: Considering each muscle of the QF, the DSI of the multi-atlas-based approach was high 0.87 ± 0.11 and the best results were obtained with the combination of two deformation fields resulting from the SyN registration method and the STEPS fusion algorithm. The optimal variables for FFD and SyN registration methods were four templates and a kernel standard deviation ranging between 5 and 8. The segmentation process using a single-atlas-based method was more robust with DSI values higher than 0.9. From the vantage of muscle volume measurements, the multi-atlas-based strategy provided acceptable results regarding the QF muscle as a whole but highly variable results regarding individual muscle. On the contrary, the performance of the single-atlas-based pipeline for individual muscles was highly comparable to the MSeg, thereby indicating that this method would be adequate for longitudinal tracking of muscle volume changes in healthy subjects. Conclusion: In the present study, we demonstrated that both multi-atlas and single-atlas approaches were relevant for the segmentation of individual muscles of the QF in healthy subjects. Considering muscle volume measurements, the single-atlas method provided promising perspectives regarding longitudinal quantification of individual muscle volumes. [ABSTRACT FROM AUTHOR]

Background: Deficits in muscle volume may be a significant contributor to physical disability in young people with cerebral palsy. However, 3D measurements of muscle volume using MRI or 3D ultrasound may be difficult to make routinely in the clinic. We wished to establish whether accurate estimates of muscle volume could be made from a combination of anatomical cross-sectional area and length measurements in samples of typically developing young people and young people with bilateral cerebral palsy.Methods: Lower limb MRI scans were obtained from the lower limbs of 21 individuals with cerebral palsy(14.7 ± 3 years, 17 male) and 23 typically developing individuals (16.8 ± 3.3 years, 16 male). The volume, length and anatomical cross-sectional area were estimated from six muscles of the left lower limb.Findings: Analysis of Covariance demonstrated that the relationship between the length*cross-sectional area and volume was not significantly different depending on the subject group. Linear regression analysis demonstrated that the product of anatomical cross-sectional area and length bore a strong and significant relationship to the measured muscle volume (R2 values between 0.955 and 0.988) with low standard error of the estimates of 4.8 to 8.9%.Interpretation: This study demonstrates that muscle volume may be estimated accurately in typically developing individuals and individuals with cerebral palsy by a combination of anatomical cross-sectional area and muscle length. 2D ultrasound may be a convenient method of making these measurements routinely in the clinic. [ABSTRACT FROM AUTHOR]

Pediatric necks present different responses and injury patterns compared with those of adults in motor vehicle crashes (MVCs). To evaluate the effect of different muscle modeling methodologies, three muscle models were developed and simulated under low-speed frontal impact conditions with an average peak acceleration of 3g's. The muscle activation curve for the curve-guided model, the muscle segment was curved using guiding nodes, was further optimized based on experimental data. The pediatric neck model was also simulated under more severe frontal impact conditions with an average peak acceleration of 8g's. Simulation results revealed that the curve-guided model needed more muscle force than the straight-guided model, in which the muscle segment was straight with guiding nodes, and the curve-constrained model, in which the muscle segment was curved without guiding nodes and which imposes more constraints on the head and neck than the curve-guided model. The predicted head responses for the child finite element neck model were within or close to the experimental corridors of 3- and 8-g's frontal impacts. The neck injuries for a 10-year-old child commonly occurred at the interspinous ligament in the C7–T1 segment. The model could be used to analyze the responses and injuries of pediatric neck and head in low-speed frontal impacts. [ABSTRACT FROM AUTHOR]

Introduction: sarcopenia is a syndrome characterized by loss of muscle mass associated with reduced muscle strength and/or reduced functional capacity. The ageing of our population is producing an increase of the prevalence related with age in addition to other factors related to malnutrition and certain diseases. The aim of this study was to provide a tool for diagnosing sarcopenia while determining in an accessible way the loss of muscle mass. Material and methods: an anthropometric standardized protocol was completed on 883 men and 506 women, healthy and active, aged 20-39 years. The following muscular development indices were calculated: body circumferences (upper arm, forearm, thigh, and calf) corrected circumferences (upper arm, thigh and calf), cross-sectional area (CSA, upper arm, thigh, and calf) and whole- body muscle mass (kg), and as a percentage (%) and in relation to height (kg/m2) by Lee's equation. The cutoff point was established as the 2.5 percentile (lower endpoint of the 95% confidence interval) for the analyzed studied. Results: significant differences by gender (p < 0.0001) were found in all the indicators analyzed. The cut-off points of the loss of skeletal muscle mass were 9,1 kg/m2 in men; and 7.3 kg/m2 in women. And in the CSA (cm2), men vs. women: upper arm, 37.7 vs. 24.2; , thigh, 154.3 vs. 115.8; and calf, 78.8 vs. 60.2. Conclusions: there is sexual dimorphism which requires considering differentiated diagnostic criteria. The anthropometric technique can serve as screening method for sarcopenia on the study of large populations. [ABSTRACT FROM AUTHOR]

Objective. The purpose of this study is to determine whether the measurements made with the device for determining muscle imbalances present in the trunk are significantly delimited by age, in order to demonstrate the sensitivity of the proposed tests. Methods. The study was conducted on 120 subjects aged from 6 to 18 years. The total sample is divided into six groups, with age as the independent variable, as follows: 6, 7, 12, 14, 16 and 18 years old. 9 tests were applied to measure muscle strength in the trunk as follows: testing of the flexion muscle strength from sitting; testing of the flexion muscle strength on the left side slope from sitting; testing of the extension muscle strength from sitting; muscle strength testing on the right side slope, from sitting; flexion muscle strength testing of standing; muscle strength testing on left lateral tilt of standing; muscle strength testing the extension from standing; muscle strength testing on the right side slope of standing; lumbar muscle strength testing (classic test). Unifactorial dispersion analysis is used (One Way ANOVA); the method by which the multiple comparisons are done by repeated measurements. Result. Mauchly's test results Test of sphericity is not statistically significant (p>0.05) and therefore the spherical condition is met. All values of F are greater than 0.05 then the null hypothesis is rejected. Conclusions. All tests have a significant sensitivity taking into account differences between subjects; in this case the independent variable is age. It highlights the differences between groups and differences between subjects in each group. Null hypothesis is rejected and the alternative hypothesis is accepted that media groups are significantly different from each other and not due to chance alone. [ABSTRACT FROM AUTHOR]

Purpose: To determine what factors should be accounted for when setting the blood flow restriction (BFR) cuff pressure for the upper and lower body. Methods: One hundred and seventy one participants visited the laboratory for one testing session. Arm circumference, muscle (MTH) and fat (FTH) thickness were measured on the upper arm. Next, brachial systolic (SBP) and diastolic (DBP) blood pressure measurements were taken in the supine position. Upper body arterial occlusion was then determined using a Doppler probe. Following this, thigh circumference and lower body arterial occlusion were determined. Models of hierarchical linear regression were used to determine the greatest predictor of arterial occlusion in the upper and lower body. Two models were employed in the upper body, a Field (arm size) and a Laboratory model (arm composition). Results: The Laboratory model explained 58 % of the variance in arterial occlusion with SBP ( β = 0.512, part = 0.255), MTH ( β = 0.363, part = 0.233), and FTH ( β = 0.248, part = 0.213) contributing similarly to explained variance. The Field model explained 60 % of the variance in arterial occlusion with arm circumference explaining the greatest amount ( β = 0.419, part = 0.314) compared to SBP ( β = 0.394, part = 0.266) and DBP ( β = 0.147, part = 0.125). For the lower body model the third block explained 49 % of the variance in arterial occlusion with thigh circumference ( β = 0.579, part = 0.570) and SBP ( β = 0.281, part = 0.231) being significant predictors. Conclusions: Our findings indicate that arm circumference and SBP should be taken into account when determining BFR cuff pressures. In addition, we confirmed our previous study that thigh circumference is the greatest predictor of arterial occlusion in the lower body. [ABSTRACT FROM AUTHOR]

Background: Clinical practice guidelines recommend objective nutritional assessments in managing chronic kidney disease (CKD) patients but were developed while referencing to a North-American population. Specific recommendations for assessing muscle mass were suggested (mid-arm circumference, MAC; corrected mid-arm muscle area, cAMA; mid-arm muscle circumference, MAMC). This study aimed to assess correlation and association of these assessments with dietary protein intake in a multi-ethnic Asian population of healthy and CKD patients. Methods: We analyzed 24-hour urine collections of selected participants to estimate total protein intake (TPI; g/day). Ideal body weight (IDW; kg) was calculated and muscle assessments conducted. Analyses involved correlation and linear regression, taking significance at p<0.05. Results: There were 232 stable CKD patients and 103 healthy participants comprising of 51.0% male, 38.5% Chinese, 29.6% Malay, 23.6% Indian, and 8.4% others. The mean TPI was 58.9±18.4 g/day in healthy participants and 53.6±19.4 g/day in CKD patients. When normalized to ideal body weight. TPI-IDW (g/kg/day) was similar in healthy and CKD participants. Overall, TPI was associated with MAC (r=0.372,p<0.001), cAMA (r=0.337, p<0.001). and MAMC (r=0.351, p<0.001). TPI-IDW was also associated with MAC (r=0.304, p<0.001), cAMA (r=0.202, /KO.OOl), and MAMC (r=0.200. p<0.001) but not for TPI normalized to actual body weight. When examined separately, TPI was associated with MAC, cAMA, and MAMC in both CKD and healthy participants, but was associated with TPI-IDW only in CKD patients. Conclusion: Total protein intake was associated with muscle assessments in all participants. TPI normalized to IDW should only be used in CKD patients. [ABSTRACT FROM AUTHOR]

Background: The B-mode ultrasound image that can measure muscle architecture is displayed side by side with the ultrasound strain elastogram that can assess muscle hardness. Consequently, muscle architecture can be measured concurrently with muscle hardness using ultrasound strain elastography. Purpose: To demonstrate the measurement of muscle architecture concurrently with muscle hardness using ultrasound strain elastography. Material and Methods: Concurrent measurements of muscle architectural parameters (muscle thickness, pennation angle, and fascicle length) and muscle hardness of the medial gastrocnemius were performed with ultrasound strain elastography. Separate measurements of the muscle architectural parameters were also performed for use as reference values for the concurrent measurements. Both types of measurements were performed twice at 20° dorsiflexion, neutral position, and 30° plantar flexion. Results: Coefficients of variance of the muscle architectural parameters obtained from the concurrent measurements (≤7.6%) were significantly higher than those obtained from the separate measurements (≤2.4%) (all P < 0.05). Intraclass correlation coefficients of the architectural parameters were lower in the concurrent measurements (≥0.74) than in the separate measurements (≥0.97). However, there were no significant differences in any muscle architectural parameters between the concurrent and separate measurements (all P > 0.05). Conclusion: The use of ultrasound strain elastography for the concurrent measurement of muscle architecture and muscle hardness is feasible. [ABSTRACT FROM AUTHOR]

Objective The purpose of this study was to evaluate the suitability of rehabilitative ultrasound imaging for quantification of medial gastrocnemius muscle in poststroke patients. Participants Thirty stroke patients (15 men and 15 women; age 64·7 ± 5·66 years; stroke duration 437·40 ± 168·24 days) participated in this study. Methods Real-time B-mode ultrasonography with a 7·5- MHz linear transducer was used to measure pennation angle and muscle thickness of the medial gastrocnemius muscles with ankle joint 90° and maximal plantar flexion. Two examiners acquired images from all participants during three separate testing sessions. After the first measurement was performed, the second measurement was performed one hour later, and the third measurement was performed 1 week later. Intraclass correlation coefficients ( ICCs(3,1)) were used for estimation of reliability. Results The ICC (95% CI) for all intra-examiner reliability was good to very good, ranging from 0·69 to 0·99 (0·51-0·99), and the ICC for all interexaminer reliability was good to very good, ranging from 0·70 to 0·99 (0·46-0·99). Conclusion In this study, the intra- and interexaminer reliability of the pennation angle and muscle thickness measurements of the medial gastrocnemius muscle was good to very good. Therefore, we suggest that the pennation angle and muscle thickness measurements of the medial gastrocnemius muscle obtained from rehabilitative ultrasound imaging would be useful for clinical assessment in poststroke patients. [ABSTRACT FROM AUTHOR]

This paper reports quantification of multivariable static ankle mechanical impedance when muscles were active. Repetitive measurements using a highly backdrivable therapeutic robot combined with robust function approximation methods enabled reliable characterization of the nonlinear torque-angle relation at the ankle in two coupled degrees of freedom simultaneously, a combination of dorsiflexion-plantarflexion and inversion-eversion, and how it varied with muscle activation. Measurements on 10 young healthy seated subjects quantified the behavior of the human ankle when muscles were active at 10% of maximum voluntary contraction. Stiffness, a linear approximation to static ankle mechanical impedance, was estimated from the continuous vector field. As with previous measurements when muscles were maximally relaxed, we found that ankle stiffness was highly direction-dependent, being weakest in inversion/eversion. Predominantly activating a single muscle or co-contracting antagonistic muscles significantly increased ankle stiffness in all directions but it increased more in the sagittal plane than in the frontal plane, accentuating the relative weakness of the ankle in the inversion-eversion direction. Remarkably, the observed increase was not consistent with simple superposition of muscle-generated stiffness, which may be due to the contribution of unmonitored deep ankle muscles. Implications for the assessment of neuro-mechanical disorders are discussed. [ABSTRACT FROM AUTHOR]

Our objective was to investigate the potential of muscle volume, measured with magnetic resonance (MR), as a biomarker to quantify disease progression in patients with amyotrophic lateral sclerosis (ALS). In this longitudinal pilot study, we first sought to determine the stability of volumetric muscle MR measurements in 11 control subjects at two time-points. We assessed feasibility of detecting atrophy in four patients with ALS, followed at three-month intervals for 12 months. Muscle power and MR volume were measured in thenar eminence (TEm), first dorsal interosseous (1DIO), tibialis anterior (TA) and tongue. Changes over time were assessed using linear regression models and t-tests. Results demonstrated that, in controls, no volumetric MR changes were seen (mean volume variation in all muscles < 5%, p > 0.1). In patients, between-subject heterogeneity was identified. Trends for volume loss were found in TEm (mean, − 26.84%, p = 0.056) and TA (− 8.29%, p = 0.077), but not in 1DIO (− 18.47%, p = 0.121) or tongue (< 5%, p = 0.367). In conclusion, volumetric muscle MR appears a stable measure in controls, and progressive volume loss was demonstrable in individuals with ALS in whom clinical weakness progressed. In this small study, subclinical atrophy was not demonstrable using muscle MR. Clinico-radiological discordance between muscle weakness and MR atrophy could reflect a contribution of upper motor neuron pathology. [ABSTRACT FROM AUTHOR]

The purpose of this study was to compare the effect of training using internal imagery (IMI; also known as kinesthetic imagery or first person imagery) with that of external imagery (EMI; also known as third-person visual imagery) of strong muscle contractions on voluntary muscle strengthening. Eighteen young, healthy subjects were randomly assigned to one of three groups (6 in each group): internal motor imagery (IMI), external motor imagery (EMI), or a no-practice control (CTRL) group. Training lasted for 6 weeks (~15 min/day, 5 days/week). The participants' right arm elbow-flexion strength, muscle electrical activity, and movement-related cortical potential (MRCP) were evaluated before and after training. Only the IMI group showed significant strength gained (10.8%) while the EMI (4.8%) and CTRL (-3.3%) groups did not. Only the IMI group showed a significant elevation in MRCP on scalp locations over both the primary motor (M1) and supplementary motor cortices (EMI group over M1 only) and this increase was significantly greater than that of EMI and CTRL groups. These results suggest that training by IMI of forceful muscle contractions was effective in improving voluntary muscle strength without physical exercise. We suggest that the IMI training likely strengthened brain-to-muscle (BTM) command that may have improved motor unit recruitment and activation, and led to greater muscle output. Training by IMI of forceful muscle contractions may change the activity level of cortical motor control network, which may translate into greater descending command to the target muscle and increase its strength. [ABSTRACT FROM AUTHOR]

Abstract: Originating from an ancient Hawaiian tradition Stand Up Paddle Surfing (SUP) is a growing pastime and sports activity in which a person stands upright on a surfboard and propels it using a single paddle. It is expected that SUP is an ideal full-body workout for amateurs as several muscle groups are required for the paddling motion. Therefore measurements of muscular activity of eight subjects were executed during on-water and treadmill-trials using wireless surface electromyography (sEMG). sEMG of 16 muscles of the trunk plus video data were acquired at three different paddling speeds. The results showed that all measured muscles of the trunk were activated and that their activity can be allocated to the different paddle-stroke phases. The study proved that although the paddle stroke is mostly performed through upper extremity activation, also the trunk as well as the hip and knee stabilizer generate power and show high muscular activation. [Copyright &y& Elsevier]

In clinical settings, the spastic catch is judged subjectively. This study assessed the psychometric properties of objective parameters that define and quantify the severity of the spastic catch in children with cerebral palsy (CP). A convenience sample of children with spastic CP (N =46; age range: 4–16years) underwent objective spasticity assessments. High velocity, passive stretches were applied to the gastrocnemius (GAS) and medial hamstrings (MEH). Muscle activity was measured with surface electromyography (sEMG), joint angle characteristics using inertial sensors and reactive torque using a force sensor. To test reliability, a group of 12 children were retested after an average of 13±9days. The angle of spastic catch (AOC) was estimated by three biomechanical definitions: joint angle at (1) maximum angular deceleration; (2) maximum change in torque; and (3) minimum power. Each definition was checked for reliability and validity. Construct and clinical validity were evaluated by correlating each AOC definition to the averaged root mean square envelope of EMG (RMS-EMG) and the Modified Tardieu Scale (MTS). Severity categories were created based on selected parameters to establish face validity. All definitions showed moderate to high reliability. Significant correlations were found between AOC3 and the MTS of both muscles and the RMS-EMG of the MEH, though coefficients were only weak. AOC3 further distinguished between mild, moderate and severe catches. Objective parameters can define and quantify the severity of the spastic catch in children with CP. However, a comprehensive understanding requires the integration of both biomechanical and RMS-EMG data. [Copyright &y& Elsevier]

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The article discusses a study on the incidence of diaphragm thinning during mechanical ventilation (MV) in patients in intensive care units (ICUs). MV leads to ventilator-induced diaphragmatic dysfunction (VIDD) based on other studies. In the present study, diaphragm muscle thickness in seven intubated patients was measured through sonography. The study shows that diaphragm muscle thinning begins within 48 hours after introducing MV.

Cervical muscles are commonly represented by line-of-action models. This investigation evaluates the performance of three types of model implementations, based on their ability to mimic geometric in-vivo aspects of muscles. Five prominent pairs of neck muscles were reconstructed in three head positions using magnetic resonance imaging. Based on the reconstructions, muscle approximations were created that represent the muscles with piecewise straight lines. Measured and modelled muscle approximations were compared with respect to their pulling directions at the attachment sites and the overall distance between the muscle paths. Muscle lengths were evaluated in two ways. First, length discrepancies were determined between measured and modelled muscles depending on the head position. Second, the difference of muscle lengths in neutral and deflected head positions for measurement and models were calculated. The results indicate considerable differences between models and measurements. Pulling directions, for instance, differed by up to 40°, depending on the chosen muscle and the type of muscle implementation. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the effects of peripheral afferent stimuli on the synchrony between brain and muscle activity as estimated by corticomuscular coherence (CMC). Electroencephalogram (EEG) from sensorimotor cortex and electromyogram (EMG) from two intrinsic hand muscles were recorded during a key grip motor task, and the modulation of CMC caused by afferent electrical and mechanical stimulation was measured. The particular stimuli used were graded single-pulse electrical stimuli, above threshold for perception and activating cutaneous afferents, applied to the dominant or non-dominant index finger, and a pulsed mechanical displacement of the gripped object causing the subject to feel as if the object may be dropped. Following electrical stimulation of the dominant index finger, the level of β-range (14-36 Hz) CMC was reduced in a stimulus intensity-dependent fashion for up to 400 ms post-stimulus, then returned with greater magnitude before falling to baseline levels over 2.5 s, outlasting the reflex and evoked changes in EMG and EEG. Subjects showing no baseline β-range CMC nevertheless showed post-stimulus increases in β-range CMC with the same time course as those with baseline β-range CMC. The mechanical stimuli produced similar modulation of β-range CMC. Electrical stimuli to the non-dominant index finger produced no significant increase in β-range CMC. The results suggest that both cutaneous and proprioceptive afferents have access to circuits generating CMC, but that only a functionally relevant stimulus produces significant modulation of the background β-range CMC, providing further evidence that β-range CMC has an important role in sensorimotor integration. [ABSTRACT FROM AUTHOR]

Youth soccer is becoming increasingly professionalized to the point of being admitted to adult teams playing in the top leagues. For this to happen it is necessary that young athletes are physically fit to meet the physical demands of professional soccer. Anthropometric assessment was performed in a total of 217 subjects divided into two groups, sub 16 and sub 17. The young players have differences in body structure with respect to professional players, showing a lack of sports development and maturation, which the evidence, the less physically fit to face the physical demands are typical of professional soccer. The muscle mass of subjects is less than professional players, so they are not suitable for inclusion in the professional team in competition matches, with the risk of injury and having a lower physical performance. [ABSTRACT FROM AUTHOR]

The study aimed at testing the possibility of using an isokinetic dynamometer to measure muscle activation level (AL). The AL measured with an isokinetic dynamometer and calculated as a ratio between the maximum isometric and eccentric torques was compared against the AL obtained by the double interpolated twitch method. Eighteen male students with different levels of training participated in the study. The average ALs measured by the isokinetic dynamometer (AL_ISOK) at knee angles of 55° and 60°, as well as the average AL calculated from the maximum eccentric torque independently of a knee angle at angular velocities of 60°/s (100.10±13.25%, 92.43±11.82% and 84.33±9.29%, respectively) and 120°/s (99.93±11.93%, 94.61±13.79% and 88.52±14.07%, respectively) did not differ significantly from the average ALs measured by the double interpolated twitch method (AL_TW=89.50±7.42%). Significant correlations were found between AL _TW and several AL _ISOK at the angular velocity of 120°/s. However, the correlations were negative and low to medium (from -.478 to -.609). It was concluded that the AL _ISOK were not comparable to the AL _TW and therefore seemed not suitable for the activation level measurement, although the negative correlations between the two methods still leave this possibility [ABSTRACT FROM AUTHOR]

Purpose: To develop a modular MR-compatible lower leg exercise device for muscle testing using a clinical 3 T MR scanner.Materials and Methods: An exercise device to provide isotonic resistance to plantar- or dorsiflexion was constructed from nonferrous materials and designed for easy setup and use in a clinical environment. Validation tests were performed during dynamic MR acquisitions. For this purpose, the device was tested on the posterior lower leg musculature of five subjects during 3 min of exercise at 30% of maximum voluntary plantarflexion during 31-phosphorus MR spectroscopy ((31)P-MRS). Measures of muscle phosphocreatine (PCr), inorganic phosphate (Pi), and pH were obtained before, during, and after the exercise protocol.Results: At the end of exercise regimen, muscle PCr showed a 28% decrease from resting levels (to 21.8 ± 3.9 from 30.4 ± 3.0 mM) and the average PCr recovery rate was 35.3 ± 8.3 s. Muscle Pi concentrations increased 123% (to 14.6 ± 4.7 from 6.5 ± 3.3 mM) and pH decreased 1.5% (to 7.06 ± 0.14 from 7.17 ± 0.07) from resting levels.Conclusion: The described MR-compatible lower leg exercise was an effective tool for data acquisition during dynamic MR acquisitions of the calf muscles. The modular design allows for adaptation to other whole-body MR scanners and incorporation of custom-built mechanical or electronic interfaces and can be used for any MR protocol requiring dynamic evaluation of calf muscles. [ABSTRACT FROM AUTHOR]

The amount and the type of dietary protein could play a role in determining the quantity of skeletal muscle mass. The aim was to examine the relationship between the type of protein intake and the level of muscle mass in healthy omnivorous and vegetarian Caucasian women. The design of the present study was an observational and cross-sectional study. Twenty-one omnivores (Om) and nineteen vegetarians (Ve) were recruited. Muscle mass index (urinary creatinine), dietary intake (5 d dietary records) and biochemical analyses (hormone, phyto-oestrogen and lipid profiles) were obtained. We found differences between groups for muscle mass (Ve: 18 kg v. Om: 23 kg; P = 0·010), muscle mass index (Ve: 6·7 kg/m2v. Om: 8·3 kg/m2; P = 0·002), animal protein intake in g/d (P = 0·001) and in g/kg body weight per d (P = 0·003), plant protein intake in g/d (P = 0·015) and in g/kg body weight per d (P = 0·007), the animal:plant protein intake ratio (P = 0·001) and sex hormone-binding globulin (SHBG) (P = 0·001). Muscle mass index still correlated with animal protein intake in g/d (P = 0·001) and in g/kg body weight per d (P = 0·008), and the animal:plant protein intake ratio (P = 0·007) even after controlling for SHBG and plant protein intake. Finally, animal protein intake (g/d) was the independent predictor of muscle mass index (adjusted r2 0·42). Thus, a vegetarian diet is associated with a lower muscle mass index than is an omnivorous diet at the same protein intake. A good indicator of muscle mass index in women seems to be animal protein intake. [ABSTRACT FROM PUBLISHER]

• The cellular and metric characteristics exhibited differences across breeds. • Honamli and Angora breeds have a far better capacity for protein synthesis. • Honamli breed could be more suitable for long term fattening practices. • Angora breed could be more suitable for short term fattening practices. Indices of the transcriptional and translational capacity of muscle cells are directly related to growth in various livestock species. The main aim of this study was, therefore, to determine cellular characteristics and their relationship with metric measurements and muscle fibers number in longissimus-dorsi (LD) and semitendinosus (ST) skeletal muscles from male kids born to Angora, Hair, Honamli and Kilis breeds. Kilis kids had significant lower (except for Hair kids) muscle cross-sectional area (MSCA) in LD and ST muscles (p<0.05). Also depth and length (except for Angora kids) of ST muscle were significantly lower (p<0.05) in Kilis kids. Honamli kids had a significant higher (p<0.05) concentrations of DNA and RNA in both muscles, while Kilis kids had a significant lower (p<0.05) total protein in ST muscle. Protein:DNA and protein:RNA ratios of Angora kids in both muscles were significantly higher compared to other breeds (p<0.05). There were positive correlations between muscle depth (MD) and protein, MSCA and DNA, MSCA and RNA, MSCA and protein (p<0.05) in LD muscle. Similarly, positive correlations between MD and protein, muscle length (ML) and RNA, ML and protein, MSCA and protein (p<0.05) were observed in ST muscle. In conclusion, Turkish indigenous goat breeds have different transcriptional and translational capacity and these differences may be used to select more efficient breeds for fattening practices. [ABSTRACT FROM AUTHOR]

The article focuses on a study conducted for serial ultrasonic measures of fat thickness (FTU) and longissimus muscle area (LMU) of steers. Hundred and eight feedlot steers representing 11 sire-breed groups were used to measure FTU at two 60-d intervals. It analyzes the relationship between carcass retail yield and real-time ultrasound measures.

The article focuses on a study conducted for serial ultrasonic measures of fat thickness (FTU) and longissimus muscle area (LMU) of steers. Hundred and eight feedlot steers representing 11 sire-breed groups were used to measure FTU at two 60-d intervals. It found that for FTU and LMU over the first five measurements, age was a source of variation.