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The American barn owl is a nocturnal bird of prey in which hind limb movements are a key factor in obtaining food; however, the architectural properties of its hind limb muscles have not been studied. This study sought to identify functional trends in the Tyto furcata hindlimb muscles by studying muscular architecture. The architectural parameters of the selected hip, knee, ankle, and digit muscles were studied in three specimens of the Tyto furcata and joint muscular proportions with an additional dataset were calculated. Previously published information on Asio otus was used for comparison. The flexor muscles of the digits had the highest muscle mass. Regarding architectural parameters, the main flexor of the digits (flexor digitorum longus) and the muscles that extend the knee and ankle joints (femorotibialis and gastrocnemius) showed a high physiological cross-sectional area (PCSA) and short fibers, allowing powerful digit flexion and knee and ankle extension. These mentioned features are in accordance with hunting behavior, in which prey capture is not only closely linked to the flexion of the digits but also to the movements of the ankle. During hunting, the distal hind limb is flexed and then fully extended at the moment of contact with the prey, whereas the digits are close to grasping the prey. The hip muscles showed a predominance of extensors over flexors, which were more massive, with parallel fibers and without tendons or short fibers. These features lead to a higher capacity to generate velocity to the detriment of forces, as indicated by the high values of the architectural index, their relatively low PCSA, and short or intermediate fiber length, which enhance the control of the joint positions and muscle length. Compared to Asio otus, Tyto furcata showed longer fibers; however, the relationship between fiber length and PCSA was similar for both species.

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The aim of this study was to determine whether increases in post-exercise endocrine response to low-load resistance exercise with blood flow restriction and high-load resistance exercise would have association with increases in muscle size and strength after an 8-week training period. Twenty-nine untrained men were randomly allocated into three groups: low-load resistance exercise with (LL-BFR) or without blood flow restriction (LL), and high-load resistance exercise (HL). Participants from LL-BFR and LL groups performed leg extension exercise at 20% of one repetition maximum (1RM), four sets of 15 repetitions and the HL group performed four sets of eight repetitions at 80% 1RM. Before the first training session, growth hormone (GH), insulin-like growth factor 1 (IGF-1), testosterone, cortisol, and lactate concentration were measured at rest and 15 min after the exercise. Quadriceps CSA and 1RM knee extension were assessed at baseline and after an 8-week training period. GH increased 15 min after exercise in the LL-BFR (p = 0.032) and HL (p < 0.001) groups, with GH concentration in the HL group being higher than in the LL group (p = 0.010). There was a time effect for a decrease in testosterone (p = 0.042) and an increase in cortisol (p = 0.005), while IGF-1 remained unchanged (p = 0.346). Both muscle size and strength were increased after training in LL-BFR and HL groups, however, these changes were not associated with the acute post-exercise hormone levels (p > 0.05). Our data suggest that other mechanisms than the acute post-exercise increase in systemic hormones induced by LL-BFR and HL produce changes in muscle size and strength.

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Introduction: Hansen's disease (HD) is the most common cause of treatable peripheral neuropathy in the world that may or may not involve skin manifestations, and physical examination based on simplified neurologic evaluation is a subjective and inaccurate procedure. High-resolution ultrasound (HRUS) can be used to evaluate peripheral nerves and is a validated technique of good reproducibility, permitting a detailed and precise examination. Objectives: We proposed to establish objective criteria for absolute values of the measurement of the CSA of peripheral nerves and their indices of the ΔCSA and ΔTpT in the diagnosis of Hansen's disease neuropathy as compared with healthy voluntaries. Materials and methods: In municipalities from different regions of Brazil, we randomly selected 234 volunteer Brazilian patients diagnosed with leprosy to be submitted to peripheral nerve echography and compared with 49 healthy Brazilian volunteers. Results: Hansen Disease assessed by high resolution ultrasound is a primarily neural disease that leads to multiple hypertrophic mononeuropathy characterized by CSA values exceeding normal limits (Med CT = 10.2 mm2; UT = 9.8 mm2; UPT = 9.3 mm2; CFFH = 18.3 mm2; T = 9.6 mm2), and the pattern of asymmetry (ΔCSA>2.5 mm2 with RR 13) and focality (ΔTPT > 2.5 mm2 with RR 6.4) of this thickening has higher sensitivity (76,1%) and specificity (87,8 %) for its early diagnosis that laboratory tests. Analyzing each subject, the percentage of thickened nerves detected among the total number of nerves assessed was higher among patients with HD than among healthy individuals (p < 0.0001). Individuals with two or more thickened nerves were at 24.1 times higher relative risk (95% CI: 6.74-88.98) of HD.

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Early life is critical for the programming of body composition. The literature links perinatal factors with fat mass development and its future effects (e.g., obesity); however, little evidence exists between early life factors and lean body mass (LBM). This study follows up on a cohort of 416 Spanish children at ages six to eight, previously evaluated at birth in the CALINA study. Here, we studied the association between early life factors, LBM, and limb strength. Parental origin/nutritional status, maternal smoking during pregnancy, gestational diabetes/weight gain/age, birth weight (BW), early feeding, and rapid weight gain (RWG) were collected from primary care records. Bioimpedance analysis, dual-energy X-ray absorptiometry, peripheral quantitative computed tomography, and a handgrip/standing long jump test were used to assess fat-free mass index (FFMI), total lean soft tissue mass index (TLSTMI), muscle cross-sectional area index (MCSAI), and limb strength, respectively. In girls, maternal smoking, gestational age, and BW were positively associated with FFM/LSTM. In boys, the parents' BMI, BW, and RWG were positively associated with FFM/LSTM. BW was associated with handgrip strength in both. Maternal BMI in girls and RWG in boys were negatively associated with the standing long jump. Early life programming plays a key role in determining LBM in children.

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Introduction: Hansen's disease (HD) primarily infects peripheral nerves, with patients without HD being free of peripheral nerve damage. Household contacts (HHCs) of patients with HD are at a 5-10 times higher risk of HD than the general population. Neural thickening is one of the three cardinal signs that define a case of HD according to WHO guidelines, exclusively considering palpation examination that is subjective and may not detect the condition in the earliest cases even when performed by well-trained professionals. High-resolution ultrasound (HRUS) can evaluate most peripheral nerves, a validated technique with good reproducibility allowing detailed and accurate examination. Objective: This study aimed to use the peripheral nerve HRUS test according to the HD protocol as a diagnostic method for neuropathy comparing HHCs with healthy volunteers (HVs) and patients with HD. Methods: In municipalities from 14 different areas of Brazil we selected at random 83 HHC of MB-patients to be submitted to peripheral nerve ultrasound and compared to 49 HVs and 176 HD-patients. Results: Household contacts assessed by HRUS showed higher median and mean absolute peripheral nerve cross-sectional area (CSA) values and greater asymmetries (ΔCSA) compared to HVs at the same points. Median and mean absolute peripheral nerve CSA values were higher in patients with HD compared to HCCs at almost all points, while ΔCSA values were equal at all points. Mean ± SD focality (ΔTpT) values for HHCs and patients with HD, respectively, were 2.7 ± 2.2/2.6 ± 2.2 for the median nerve, 2.9 ± 2.7/3.3 ± 2.9 for the common fibular nerve (p > 0.05), and 1.3 ± 1.3/2.2 ± 3.9 for the ulnar nerve (p < 0.0001). Discussion: Considering HRUS findings for HHCs, asymmetric multiple mononeuropathy signs (thickening or asymmetry) in at least 20% of the nerves evaluated could already indicates evidence of HD neuropathy. Thus, if more nerve points are assessed in HHCs (14 instead of 10), the contacts become more like patients with HD according to nerve thickening determined by HRUS, which should be a cutting-edge tool for an early diagnosis of leprosy cases.

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The present study investigated the associations between physical activity (PA) and physical fitness (PF) with lean body mass (LBM) and evaluated whether PA mediates the association between PF and LBM. 279 children (150 boys) aged 7.5 ± 0.3 years participated in the study. PA was assessed by accelerometry and PF with handgrip and the standing long jump test. Total lean soft tissue mass index (TLSTMI), muscle cross-sectional area index (MCSAI), and fat-free mass index (FFMI) were evaluated using dual-energy X-ray absorptiometry, peripheral quantitative computed tomography, and bioimpedance analysis, respectively.Total (ß = 0.247) and vigorous PA (ß = 0.143) were associated with TLSTMI in girls. In boys, total (ß = 0.337), light (ß = 0.290), vigorous (ß = 0.200), and moderate-vigorous PA (ß = 0.189) were associated with TLSTMI. Total PA was associated with FFMI (ß = 0.299). Handgrip strength does not mediate the relationship between total PA and TLSTMI. Positive associations were found between handgrip strength and TLSTMI, MCSAI, and FFMI in both girls and boys.In children, there is a positive association between total and vigorous PA with TLSTMI. Handgrip strength does not mediate the relationship between total PA and TLSTMI. It was associated with TLSTMI, MCSAI, and FFMI.

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ABSTRACT Introduction: Smartphone overuse may lead to musculoskeletal manifestations, such as carpal tunnel syndrome (CTS) and arthritis of hand joints, with an increased median nerve cross-sectional area (CSA). Objective: The aim of this study is the early detection of musculoskeletal hand disorders using ultrasound techniques, and to detect nerve entrapment using clinical evaluation, ultrasound, and electrophysiological studies, in university employees younger than 35 years using mobile phones. Function is assessed using the Michigan Hand Outcomes Questionnaire (MHQ). Materials and methods: Cross-sectional controlled study included 74 smartphone users classified into two groups according to a smartphone addiction scale (SAS), into high and low smart phone users, with 35 non-smartphone users with matched age and gender as a control group. A clinical assessment of nerve entrapment symptoms was performed, and the Michigan Hand Outcomes Questionnaire (MHQ), with a total score from 0 to100, was used to assess hand function. Electrodiagnostic studies of median and ulnar nerves were used to detect early nerve entrapment. Bilateral ultrasound was performed in order to assess the median nerve CSA and involvement of thumb and small hand joints. The data collected were analyzed using the SPSS program version 20. Results: CSAs of median nerves were significantly higher in the dominant hand of high smartphone users than in low and non-smartphone users (p < 0.001). There was a significant positive correlation between CSA and SAS (r = 0.45), visual analogue scale (VAS) (r = 0.61), and duration of smartphone use (r = 0.80), with negative correlation with MHQ (r = -0.63). Significant differences in were found in the electrophysiological studies of median and ulnar nerves. The mean ultrasound score for both hands was higher in the high smartphone users compared to low smartphone users (15.08 ± 4.17 vs. 6.46 ± 1.38, p < .001). Conclusions: There is increased median nerve CSAs among high smartphone users associated with prolongation of both sensory and motor latencies and slow conduction velocities. Caution should be exercised when using mobile phones, in order to minimize the risk of developing hand musculoskeletal disorders.

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BACKGROUND: This study investigated the effects of two 14-week resistance training protocols with different repetition duration (RD) performed to muscle failure (MF) on gains in strength and muscle hypertrophy as well as on normalized electromyographic (EMG) amplitude and force-angle relationships. METHODS: The left and right legs of ten untrained males were assigned to either one of the two protocols (2-s or 6-s RD) incorporating unilateral knee extension exercise. Both protocols were performed with 3-4 sets, 50-60% of the one-repetition maximum (1RM), and 3 min rest. Rectus femoris and vastus lateralis cross-sectional areas (CSA), maximal voluntary isometric contraction (MVIC) at 30o and 90o of knee flexion and 1RM performance were assessed before and after the training period. In addition, normalized EMG amplitude-angle and force-angle relationships were assessed in the 6th and 39th experimental sessions. RESULTS: The 6-s RD protocol induced larger gains in MVIC at 30o of knee angle measurement than the 2-s RD protocol. Increases in MVIC at 90o of knee angle, 1RM, rectus femoris and vastus lateralis CSA were not significant between the 2-s and 6-s RD protocols. Moreover, different normalized EMG amplitude-angle and force-angle values were detected between protocols over most of the angles analyzed. CONCLUSION: Performing longer RD could be a more appropriate strategy to provide greater gains in isometric maximal muscle strength at shortened knee positions. However, similar maximum dynamic strength and muscle hypertrophy gains would be provided by protocols with different RD.

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BACKGROUND: Skeletal muscle is one of the main components of lean soft tissue mass (LSTM). Low levels in children affect locomotion, posture, and increase the risk of metabolic syndrome. AIM: (1) To evaluate the association between muscle cross-sectional area (MCSA) of the lower left leg measured by peripheral quantitative computed tomography (pQCT) and total LSTM; namely, total left leg and left lower leg LSTM assessed by dual-energy X-ray absorptiometry (DXA) in a group of children, (2) to examine if MCSA is a predictor of LSTM, (3) to determine the ability of pQCT to identify children with low LSTM. SUBJECTS AND METHODS: Lower left leg MCSA and LSTM were measured using pQCT and DXA, respectively, in 396 children. RESULTS: Statistically significant positive correlations were found between the lower leg MCSA - total LSTM (r² = 0.789), total leg LSTM (r² = 0.79), and lower leg LSTM (r² = 0.791) (p < .01). MCSA explained 64-68% of the variance in LSTM. Receiver operator characteristic (ROC) curves determined the capacity of the lower left leg MCSA to identify low LSTM in girls (AUC 0.95) and boys (AUC 0.87). CONCLUSIONS: Our results showed that lower left leg MCSA, measured using pQCT, could be a tool to predict low LSTM in children.

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This study aimed to review the effects of ladder-based resistance training (LRT) on muscle hypertrophy and strength in rodents through a systematic review with meta-analysis. We systematically searched PubMed/Medline, SportDiscuss, Scopus, Google Scholar, Science Direct, and Scielo database on May 18, 2020. Thirty-four studies were included measuring total (mCSA) or mean muscle fibers cross-sectional area (fCSA) or maximum load-carrying capacity (MLCC) or muscle mass (MM). About the main results, LRT provides sufficient mechanical stimulation to increase mCSA and fCSA. Meta-analysis showed a significant overall effect on the fCSA (SMD 1.89, 95% CI [1.18, 2.61], p < .00001, I2  = 85%); however, subgroup analysis showed that some muscle types might not be hypertrophied through the LRT. Meta-analysis showed a significant training effect on the MM (SMD 0.92, 95% CI [0.52, 1.32], p < .00001, I2  = 72%). Sub-group analysis revealed that soleus (SMD 1.32, 95% CI [0.11, 2.54], p = .03, I2  = 86%) and FHL (SMD 1.92, 95% CI [1.00, 2.85], p < .0001, I2  = 71%) presented significant training effects, despite moderate heterogeneity levels (I2  = 72%). MLCC increases considerably after a period of LRT, regardless of its duration and the characteristics of the protocols (SMD 12.37, 95% CI [9.36, 15.37], p < .00001, I2  = 90%). Through these results, we reach the following conclusions: (a) LRT is efficient to induce muscle hypertrophy, although this effect varies between different types of skeletal muscles, and; (b) the ability of rodents to carry load increases regardless of the type and duration of the protocol used.

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Purpose: The purpose of this study was to determine whether there is a difference in the change in cross-sectional area (CSA) of the median nerve in patients undergoing carpal tunnel release (CTR) based on surgical technique and whether this change is associated with changes in patient-reported outcomes evaluated using the Carpal Tunnel Syndrome Assessment Questionnaire. Methods: Individuals with carpal tunnel syndrome were evaluated with ultrasound and the CTSAQ before and 6 weeks after surgery. Patients were eligible for inclusion if they underwent either a mini-open CTR (MOCTR) or endoscopic CTR (ECTR). A single surgeon performed all surgeries. Changes in median nerve CSA, Carpal Tunnel Syndrome Assessment Questionnaire scores, and their associated surgical technique (MOCTR vs ECTR) were analyzed. Results: A total of 77 patients were enrolled, 13 of whom were lost to follow-up, which left 64 for analysis. Of those, 42 patients underwent ECTR and 22 MOCTR. Mean age was 55 years; there were 52 women and 12 men. Mean changes in CSA for endoscopic and mini-open techniques from before to 6 weeks after surgery were -1.9 mm2 (95% confidence interval [CI], -1.1 to -2.7) and +0.6 mm2 (95% CI, -1.6 to 0.4), respectively. Mean Symptom Severity Scores improved after endoscopic and mini-open release by 1.7 (95% CI, 1.4-2.1) and 1.5 (95% CI, 1.2-1.9), respectively. Mean Functional Status Scores improved after endoscopic and mini-open release by 1.2 (95% CI, 0.9-1.9) and 0.7 (95% CI, 0.03-1.3), respectively. Conclusions: Patients undergoing ECTR demonstrated decreased median nerve CSA, whereas those undergoing MOCTR demonstrated increased median nerve CSA at 6 weeks. All patients undergoing surgical intervention demonstrated improvement in both Symptom Severity Scores and Functional Status Scores after surgery. Whereas both techniques successfully improve patient outcome scores, an increase in CSA after MOCTR may be seen in the initial postoperative period, potentially contributing to a slower short-term improvement in outcome in functional scores compared with ECTR. Type of study/level of evidence: Therapeutic IV.

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This study investigated the effects of maturity status on knee extensor torque and vastus lateralis architecture of young soccer players. Thirty-four males aged 13-18 years were divided into two groups: pubescent (PUB, n = 15) and postpubescent (POSP, n = 19). Torque by angle interaction was established for absolute [F(2.649, 84.771) = 9.066, p < 0.05] and relative to body mass [F(2.704, 86.533) = 4.050, p < 0.05] isometric torque with the POSP group showing greater values. Muscle volume torque-angle relationship was similar between groups. Absolute, relative to body mass, and relative to muscle volume concentric and eccentric torque-velocity relationship showed a non-significant interaction but a significant group effect in favour the POSP group for absolute and concentric torque relative to body mass. Torque-angle and torque-velocity relationship normalized by body mass allometric exponents showed a non-significant interactions and group effects. Muscle thickness (3.6 ± 0.6 vs. 3.8 ± 0.6 cm), fascicle length (8.3 ± 1.4 vs. 8.9 ± 1.6 cm) and pennation angle (15.0 ± 2.3 vs. 14.3 ± 3.2 degrees) was similar between PUB and POSP groups, respectively. Maturity status did not show a significant effect on muscle architecture and on isometric and dynamic torques when allometrically normalized.

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ABSTRACT There are a plethora of studies that have analyzed the effects of different resistance training methods on muscle hypertrophy. Recent studies have pointed out some potential advantage of training using cluster sets (CS) compared with traditional sets. It is still unclear whether CS are an effective method. The objective of this review was to investigate and discuss the current knowledge about the effect of CS on muscle hypertrophy. Four studies investigating the effect of CS on muscle hypertrophy were found. These studies demonstrated that CS induced similar or lower muscle hypertrophy than traditional sets. Thus, CS may lead to muscle hypertrophy, but did not provide a superior stimulus when compared to traditional sets of equated load.

RESUMO Um conjunto de estudos que tem analisado o efeito de diferentes métodos de treinamento resistido na hipertrofia muscular. Estudos têm pontuado várias potenciais vantagens do treinamento usando séries em conglomerados (SC) quando comparado com séries tradicionais. Ainda não está claro se as SC é um método efetivo. O objetivo desta revisão foi investigar e discutir o conhecimento recente sobre o efeito das SC na hipertrofia muscular. Quatro estudos investigando o efeito das SC na hipertrofia muscular foram encontrados. Esses estudos demonstraram que as SC induziram similar ou menor hipertrofia muscular do que séries tradicionais. Portanto, as SC podem induzir hipertrofia, porém não fornecem um estímulo superior quando comparado às séries tradicionais com carga equiparada.

RESUMEN Muchos estudios han analizado los efectos de diferentes métodos de entrenamiento de la fuerza en la hipertrofia muscular. Algunos estudios han resaltado las ventajas de introducir períodos de recuperación intra-serie (series cluster, SC) al compararlo con las series tradicionales. No está todavía claro si las SC son un método efectivo. El objetivo de esta revisión fue investigar y discutir el conocimiento actual sobre el efecto de las SC en la hipertrofia muscular. Se encontraron cuatro estudios investigando el efecto de las SC en la hipertrofia. Estos estudios demuestran que las SC inducen igual o menor hipertrofia que las series tradicionales. Así, las SC podrían inducir hipertrofia muscular pero no proporcionan un estímulo superior al compararlas con las series tradicionales.

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The aim of the study was to compare the effect of resistance training (RT) frequencies of five times (RT5), thrice- (RT3) or twice- (RT2) weekly in muscle strength and hypertrophy in young men. Were used a within-subjects design in which 20 participants had one leg randomly assigned to RT5 and the other to RT3 or to RT2. 1 RM and muscle cross-sectional area (CSA) were assessed at baseline, after four (W4) and eight (W8) RT weeks. RT5 resulted in greater total training volume (TTV) than RT3 and RT2 (P = .001). 1 RM increased similarly between protocols at W4 (RT5: 55 ± 9 Kg, effect size (ES): 1.18; RT3: 51 ± 11 Kg, ES: 0.80; RT2: 54 ± 7 Kg, ES: 1.13; P < .0001) and W8 (RT5: 62 ± 11 Kg, ES: 1.81; RT3: 57 ± 11 Kg, ES: 1.40; RT2: 60 ± 8 Kg, ES: 1.98; P < .0001) vs. baseline (RT5: 45 ± 9 Kg; RT3: 42 ± 11 Kg; RT2: 46 ± 7 Kg). CSA increased similarly between protocols at W4 (RT5: 24.6 ± 3.9 cm2, ES: 0.54; RT3: 22.0 ± 4.6 cm2, ES: 0.19; RT2: ES: 0.25; 23.8 ± 3.8 cm2; P < .001), and W8 (RT5: 25.3 ± 4.3 cm2; ES: 0.69; RT3: 23.6 ± 4.2 cm2, ES: 0.58; RT2: 25.5 ± 3.7 cm2; ES: 0.70; P < .0001) vs. baseline (RT5: 22.5 ± 3.8 cm2; RT3: 21.2 ± 4.0 cm2; RT2: 22.9 ± 3.8 cm2). Performing RT5, RT3 and RT2 a week result in similar muscle strength increase and hypertrophy, despite higher TTV for RT5.

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STUDY DESIGN: Retrospective comparative clinical study. PURPOSE: This study aimed to assess paraspinal muscle atrophy in patients who underwent minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) and unilateral pedicle screw fixation using a novel contralateral intact muscle-controlled model. OVERVIEW OF LITERATURE: The increased incidence of paravertebral lumbar muscle injuries after open techniques has raised the importance of implementing minimally invasive spine surgical techniques using tubular retractors and minimally invasive screw placement. The functional cross-sectional area (FCSA) represents the lean muscle mass; furthermore, FCSA is a useful marker of the contractile ability of a muscle following a spine surgery. However, the benefits of unilateral fixation and MI-TLIF on paraspinal muscles have not been defined. METHODS: We performed a retrospective imagenological review on eleven patients who underwent unilateral MI-TLIF and unilateral transpedicular screw lumbar placement. FCSAs of the multifidus and erector spinae were measured 1 year after surgery at adjacent levels and were compared to the contralateral intact muscles. Measurement differences between the surgical and nonsurgical sites were compared. The interobserver reliability was calculated using an intraclass correlation coefficient. RESULTS: The mean FCSA at the surgical site was 20.97±5.07 cm2 at the superior level and 8.89±2.87 cm2 at the inferior level. The mean FCSA at the contralateral nonsurgical site was 20.15±5.95 cm2 at the superior level and 9.20±2.66 cm2 at the inferior level was. The superior and inferior FCSA measurements showed no significant difference between the surgical and nonsurgical sites (p=0.5, p=0.922, respectively). CONCLUSIONS: Using a mini-open tubular approach through the sulcus between the longissimus and iliocostalis, MI-TLIF and unilateral pedicle screw instrumentation produced minimal paraspinal muscle damage at the superior and inferior adjacent levels.

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PURPOSE: Lumbar paraspinal muscle morphology has recently been evaluated in several studies with conflicting results. Several studies have performed single-slice evaluations of paraspinal muscle morphology, whereas other studies have done a multi-level assessment; this methodological difference might explain the observed different results. Our study evaluated if a single-slice axial measurement is representative of the entire lumbar musculature. METHODS: We included 80 adult patients who were consecutively evaluated with magnetic resonance imaging (MRI) for spinal symptoms. Using T2-weighted axial images, we measured the fat signal fractions (FSF) and cross-sectional area (CSA) of the erector spinae and multifidus at the five levels of the lumbar spine (from L1-L2 to L5-S1). We used the ANOVA test for repeated measurements (with Bonferroni correction) to compare the FSF and CSA among the levels. RESULTS: Erector spinae showed an increasing FSF from L1-L2 to L5-S1; all erector spinae FSF comparisons among the different levels were significantly different. Multifidus FSF also increased caudally below L2-L3, although significant differences were observed only with two or more levels of distance. The CSA of the erector spinae showed a caudal decrease (L4-L5 and L5-S1 being significantly smaller than all the levels above). The CSA of the multifidus showed that all levels exhibited a significantly different area compared to their adjacent level (except L5-S1 compared to L4-L5). CONCLUSIONS: No single-level FSF or CSA is representative of the whole lumbar spine. A standardized multi-level evaluation of the paraspinal musculature should be used in future research.

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PURPOSE: To determine the association of paraspinal muscles and psoas relative cross-sectional area (RCSA) and fat signal fraction (FSF) with sex, age, and intervertebral disc degeneration (IDD) in symptomatic patients. METHODS: We retrospectively evaluated 80 adult patients with spinal symptoms using T2-weighted magnetic resonance images. We determined RCSA and FSF of the paraspinal muscles (erector spinae and multifidus) and psoas from L1-L2 to L5-S1; we determined IDD using the Pfirrmann classification. We compared differences in muscle RCSA and FSF based on sex and IDD, and we correlated age and IDD with RCSA and FSF. Using multivariate linear regression analyses, we determined the impact of sex, age, and IDD on RCSA and FSF. RESULTS: Men exhibited larger psoas RCSA but not larger paraspinal muscles RCSA than women. Women had larger FSF in the paraspinal muscles and psoas. Increasing IDD was associated with larger FSF if ≥2 Pfirrmann grades were observed. IDD correlated with FSF of the paraspinal muscles, and age correlated with FSF of the paraspinal muscles and psoas. IDD was less consistently correlated with RCSA, but age correlated negatively with RCSA of all three muscles. Linear regression analyses demonstrated that sex, age, and IDD were each independently associated with FSF of the paraspinal muscles; additionally, sex and age, but not IDD, were associated with psoas FSF. RCSA was less consistently influenced by these three variables. CONCLUSIONS: Sex, age, and IDD are independently associated with paraspinal muscles FSF; only sex and age influence psoas FSF.

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BACKGROUND: Resistance training (RT) for upper body muscle hypertrophy (UBMH) typically entails high volumes of sets per muscle group per training session. The majority of RT regimens does not discriminate between upper and lower body muscle groups, while these groups may respond differently to RT set volumes in terms of maximum skeletal muscle mass gain. Recent studies have examined the effect of different set volumes on the extent of UBMH to formulate optimal RT regimens and to make RT programmes more time-efficient. OBJECTIVE: To analyse the effect of the number of RT sets on the extent of UBMH on the basis of recent literature. RESULTS AND CONCLUSION: The analysis suggests that, statistically, high set volumes (≥3) are not significantly better than low set volumes (<3) in regard to UBMH in untrained subjects. For trained subjects, the literature is lacking in well-designed studies comparing low and high training volumes, as well as analysing upper and lower body muscles separately. Therefore, it is not possible to conclude that high volume of sets offers better results than low volume of sets for UBMH, and vice versa.

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Abstract AIM the aim of this study was to analyze the weekly sets volume (WSV) performed by trained men and women for each muscle group in muscle hypertrophy programs. METHODS One hundred and five resistance training practitioners of both sex (42 women, 29.8±5.7 years; 63 men, 28.5±5.7 years) consented to the analysis of their current training programs. Their training plains were analyzed by a researcher that used the following equation to determine the WSV performed for each muscle group: "number of exercises per muscle group per training session X number of sets per exercise in each training session X weekly training frequency per muscle group". The median values ​​by each muscle group were compared within and between genders. RESULTS Between group analysis demonstrated that men performed higher WSV for upper body (UB) muscles than women (47.2±14,6 vs. 18.2±7.4 sets). Conversely, women performed a higher WSV for lower body (LB) muscle groups than men (23.8±11.2 vs. 11.5±7.0 sets). The training volume for the abdominal muscles did not differ between groups. When comparing the WSV for the UB, LB and core musculature within groups, men perform higher training volumes for the UB compared to the LB and core, while women train the LB with a higher volume compared to the other musculature. CONCLUSION For some muscle groups, the WSV is higher than recommended in the literature for muscle hypertrophy. Men emphasize the UB training, while women emphasize training the LB. Moreover, the WSV performed by subjects of both genders is disproportionate between different muscle groups.

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The purpose of this study was to examine the effects of free leucine supplementation on changes in skeletal muscle mass and strength during a resistance training (RT) program in previously untrained, young subjects. In a double-blind, randomized, placebo-controlled study, 20 healthy young (22 ± 2 years) participants were assigned to two groups: a placebo-supplement group (PLA, N = 10) or a leucine-supplement group (LEU, N = 10). Both groups underwent an 8-week hypertrophic RT program (2 days/week), consuming an equivalent amount of leucine (3.0 g/day in a single post-training dose) or placebo (cornstarch). Quadriceps muscle strength, cross-sectional area (CSA) of the vastus lateralis (VL), and rectus femoris (RF), as well as the habitual dietary intake were assessed before and after the 8-week intervention period. There was a similar improvement in muscle strength (Leg press, LEU: +33% vs. PLA: +37%; P > 0.05, and knee extension, LEU: +31% vs. PLA: 34%; P > 0.05) and CSA (VL, LEU: 8.9% vs. PLA: 9.6%; P > 0.05, and RF, LEU: +21.6% vs. PLA: + 16.4%; P > 0.05) in the both groups from pre- to post-training. In addition, there was no significant (P > 0.05) difference in daily dietary intake between the LEU and PLA groups before and after the intervention period. Free leucine supplementation (3.0 g/day post-training) does not increase muscle strength or CSA during RT in healthy young subjects consuming adequate dietary protein intake.

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