Search

This work evaluates the technical feasibility of a roller-compacted concrete (RCC) pavement with complete replacement of natural aggregates by electric arc furnace slag (EAFS) or basic oxygen furnace slag (BOFS). The methodology includes, initially, the processing of the slags, and physical, chemical, and environmental characterization of the natural and slag aggregates. Subsequently, concrete mixtures were designed, and the compaction at optimum moisture was performed. Finally, the behavior of specimens under service and their mechanical performance were evaluated. Results show that both EAFS and BOFS enhance the RCC's compressive strength and modulus of elasticity. The RCC produced with BOFS aggregates presented some expansibility due to its high contents of chemically active finer-than-75-µm materials and higher porosity. The EAFS aggregate was stable in durability analysis. In conclusion, through optimal mixture proportions and using compatible energy compression, it is viable to produce pavements with EAFS steelmaking slag in efficient, economical, and environmentally friendly manners. BOFS also showed promising results but requires further investigation. [ABSTRACT FROM AUTHOR]

Objective: Existing literature indicates that females generally demonstrate higher fatigue resistance than males during isometric contractions. However, when it comes to single-limb dynamic exercises, the intricate interplay between performance fatigability (PF), cardiovascular responses, and muscle metabolism in relation to sex differences remains underexplored., Purpose: This study investigates how sex affects the relationship between muscle oxidative characteristics and the development of PF during dynamic single-leg exercise., Methods: Twenty-four young healthy participants (12 males vs 12 females) performed a constant-load single-leg knee extension task (85% peak power output; 60 rpm) to exhaustion (TTE). Neuromuscular assessments via transcranial magnetic and peripheral stimulations were conducted before and after exercise to evaluate central and peripheral factors of PF. Vastus lateralis muscle biopsies were obtained for mitochondrial respiration and immunohistochemistry analyses., Results: Participants performed similar total work (28 ± 7 vs 27 ± 14 kJ, P = 0.81) and TTE (371 ± 139 vs 377 ± 158 s, P = 0.98); after the TTE, females' maximal isometric voluntary contraction (MVIC: -36% ± 13% vs -24% ± 9%, P = 0.006) and resting twitch (RT; -65% ± 9% vs -40% ± 24%, P = 0.004) force declined less. No differences were observed in supraspinal neuromuscular factors ( P > 0.05). During exercise, the cardiovascular responses differed between sexes. Although fiber type composition was similar (type I: 47% ± 13% vs 56% ± 14%, P = 0.11), males had lower mitochondrial net oxidative capacity (61 ± 30 vs 89 ± 37, P = 0.049) and higher Complex II contribution to maximal respiration (CII; 59% ± 8% vs 48% ± 6%, P < 0.001), which correlated with the decline in MVIC ( r = -0.74, P < 0.001) and RT ( r = -0.60, P = 0.002)., Conclusions: Females display greater resistance to PF during dynamic contractions, likely due to their superior mitochondrial efficiency and lower dependence on mitochondrial CII activity., (Copyright © 2024 by the American College of Sports Medicine.)

Short-term unloading experienced following injury or hospitalisation induces muscle atrophy and weakness. The effects of exercise following unloading have been scarcely investigated. We investigated the functional and molecular adaptations to a resistance training (RT) programme following short-term unloading. Eleven males (22.09 ± 2.91 years) underwent 10 days of unilateral lower limb suspension (ULLS) followed by 21 days of knee extensor RT (three times/week). Data collection occurred at Baseline (LS0), after ULLS (LS10) and at active recovery (AR21). Knee extensor maximum voluntary contraction (MVC) was evaluated. Quadriceps volume was estimated by ultrasonography. Muscle fibre cross-sectional area, fibre type distribution, glycogen content and succinate dehydrogenase (SDH) activity were measured from vastus lateralis biopsies. Mitochondrial-related proteins were quantified by western blot and transcriptional responses were assessed by RNA sequencing. Following ULLS, quadriceps volume and MVC decreased significantly (3.7%, P < 0.05; 29.3%, P < 0.001). At AR21 (vs. LS10), MVC was fully restored (42%) and quadriceps volume increased markedly (18.6%, P < 0.001). Glycogen content and whole-body water increased at AR21 (14%, P < 0.001; 3.1%, P < 0.05). We observed a marked increase in fibre type I at AR21 (38%, P < 0.05). SDH immunoreactivity increased significantly after exercise (20%, P < 0.001). Mitochondrial fusion (MFN1, MFN2 and OPA1) and fission (DRP1) proteins were markedly increased by RT, and the most differentially expressed genes belonged to oxidative phosphorylation pathways. In contrast with what is usually observed after RT, oxidative metabolism, slow fibre type and mitochondrial dynamics were enhanced beyond expected. We propose that prior exposure to short-term muscle unloading may drive the nature of molecular adaptations to subsequent RT. KEY POINTS: Short-term unloading is often experienced during recovery from injuries and hospitalisation, leading to loss of muscle mass and strength. Although exercise can be beneficial in mitigating/reversing such alterations during disuse, only a few studies have focused on the effects of exercise following muscle unloading. With an integrative physiological approach, we aimed to elucidate the basic mechanisms of muscle function recovery in response to 21 days of resistance exercise that followed 10 days of unilateral lower limb suspension (ULLS), assessing whether the mechanisms underlying recovery are defined by a specific reversal of those that occurred during disuse. Resistance training was successful in recovering functional and structural muscle properties after 10 days of ULLS, but in contrast with what is usually observed in response to this training modality, oxidative metabolism and slow fibre type were mostly enhanced. We propose that prior exposure to short-term muscle unloading may drive the adaptations to subsequent exercise., (© 2025 The Author(s). The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.)

Purpose: While cycling offers several health benefits, repetitive loading and maintenance of static postures for prolonged periods expose cyclists to low back pain (LBP). Despite high LBP prevalence in cyclists, underlying pathomechanics and specific lumbar region muscle activation patterns during cycling are unclear. Here, we compared lumbar erector spinae (ES) muscles activation and spatial distribution activity in cyclists with and without recent LBP history., Methods: Ten cyclists with recent LBP history (LBPG; Oswestry Disability Index score ~ 17.8%) and 11 healthy cyclists (CG) were recruited. After assessing the Functional Threshold Power (FTP), participants underwent an incremental cycling test with 4 × 3 min steps at 70%, 80%, 90%, and 100% of their FTP. High-density surface electromyography (HDsEMG) signals were recorded from both lumbar ES using two 64-channel grids. Information about ES activation levels (root-mean-square, RMS), degree of homogeneity (entropy), and cranio-caudal displacement of muscle activity (Y-axis coordinate of the barycenter of RMS maps) was extracted from each grid separately and then grand-averaged across both grids., Results: Repeated-measure 2-way ANOVAs showed a significant intensity by group interaction for RMS amplitude (p = 0.003), entropy (p = 0.038), and Y-bar displacement (p = 0.033). LBPG increased RMS amplitude between 70-100% (+ 19%, p = 0.010) and 80-100% FTP (+ 21%, p = 0.004) and decreased entropy between 70-100% FTP (- 8.4%, p = 0.003) and 80-100% FTP (- 8.5%, p = 0.002). Between-group differences emerged only at 100% FTP (+ 9.6%, p = 0.049) for RMS amplitude., Conclusion: Our findings suggest that cyclists with recent LBP history exhibit higher ES muscles activation and less homogeneous activity compared to healthy controls, suggesting potential inefficient muscle recruitment strategy., Trial Registration Number: HEC-DSB/09-2023., (© 2024. The Author(s).)

Background: Degeneration of the motoneuron and neuromuscular junction (NMJ) and loss of motor units (MUs) contribute to age-related muscle wasting and weakness associated with sarcopenia. However, these features have not been comprehensively investigated in humans. This study aimed to compare neuromuscular system integrity and function at different stages of sarcopenia, with a particular focus on NMJ stability and MU properties., Methods: We recruited 42 young individuals (Y) (aged 25.98 ± 4.6 years; 57% females) and 88 older individuals (aged 75.9 ± 4.7 years; 55% females). The older group underwent a sarcopenia screening according to the revised guidelines of the European Working Group on Sarcopenia in Older People 2. In all groups, knee extensor muscle force was evaluated by isometric dynamometry, muscle morphology by ultrasound and MU potential properties by intramuscular electromyography (iEMG). MU number estimate (iMUNE) and blood samples were obtained. Muscle biopsies were collected in a subgroup of 16 Y and 52 older participants., Results: Thirty-nine older individuals were non-sarcopenic (NS), 31 pre-sarcopenic (PS) and 18 sarcopenic (S). A gradual decrease in quadriceps force, cross-sectional area and appendicular lean mass was observed across the different stages of sarcopenia (for all P < 0.0001). Handgrip force and the Short Physical Performance Battery score also showed a diminishing trend. iEMG analyses revealed elevated near fibre segment jitter in NS, PS and S compared with Y (Y vs. NS and S: P < 0.0001; Y vs. PS: P = 0.0169), suggestive of age-related impaired NMJ transmission. Increased C-terminal agrin fragment (P < 0.0001) and altered caveolin 3 protein expression were consistent with age-related NMJ instability in all the older groups. The iMUNE was lower in all older groups (P < 0.0001), confirming age-related loss of MUs. An age-related increase in MU potential complexity was also observed. These observations were accompanied by increased muscle denervation and axonal damage, evinced by the increase in neural cell adhesion molecule-positive fibres (Y vs. NS: P < 0.0001; Y vs. S: P = 0.02) and the increase in serum concentration of neurofilament light chain (P < 0.0001), respectively. Notably, most of these MU and NMJ parameters did not differ when comparing older individuals with or without sarcopenia., Conclusions: Alterations in MU properties, axonal damage, an altered innervation profile and NMJ instability are prominent features of the ageing of the neuromuscular system. These neuromuscular alterations are accompanied by muscle wasting and weakness; however, they appear to precede clinically diagnosed sarcopenia, as they are already detectable in older NS individuals., (© 2024 The Author(s). Journal of Cachexia, Sarcopenia and Muscle published by Wiley Periodicals LLC.)

Obesity is defined as a complex, systemic disease characterized by excessive and dysfunctional adipose tissue, leading to adverse health effects. This condition is marked by low-grade inflammation, oxidative stress, and metabolic abnormalities, including mitochondrial dysfunction. These factors promote energy dysregulation and impact body composition not only by increasing body fat but also by promoting skeletal muscle mass atrophy. The decline in muscle mass is associated with an increased risk of all-cause mortality in individuals with this disease. The European Food Safety Authority approved pyrroloquinoline quinone (PQQ), a natural compound, as a dietary supplement in 2018. This narrative review aims to provide a comprehensive overview of the potential role of PQQ, based on its anti-inflammatory and antioxidant properties, in addressing dysfunctional adipose tissue metabolism and related disorders.

Flow-mediated dilation (FMD) is a common measure of endothelial function and an indicator of vascular health. Automated software methods exist to improve the speed and accuracy of FMD analysis. Compared with commercial software, open-source software offers similar capabilities at a much lower cost while allowing for increased customization specific to users' needs. We introduced modifications to an existing open-source software, FloWave.us to better meet FMD analysis needs. The purpose of this study was to compare the repeatability and reliability of the modified FloWave.us software to the original software and to manual measurements. To assess these outcomes, duplex ultrasound imaging data from the popliteal artery in older adults were analyzed. The average percent FMD for the modified software was 6.98 ± 3.68% and 7.27 ± 3.81% for observer 1 and 2 respectively, compared with 9.17 ± 4.91% and 10.70 ± 4.47% with manual measurements and 5.07 ± 31.79% with the original software for observer 1 . The modified software and manual methods demonstrated higher intraobserver intraclass correlation coefficients (ICCs) for repeated measures for baseline diameter, peak diameter, and percent FMD compared with the original software. For percent FMD, the interobserver ICC was 0.593 for manual measurements and 0.723 for the modified software. With the modified method, an average of 97.7 ± 2.4% of FMD videos frames were read, compared with only 17.9 ± 15.0% frames read with the original method when analyzed by the same observer. Overall, this work further establishes open-source software as a robust and viable tool for FMD analysis and demonstrates improved reliability compared with the original software. NEW & NOTEWORTHY This study improves edge detection capabilities and implements noise reduction strategies to optimize an existing open-source software's suitability for flow-mediated dilation (FMD) analysis. The modified software improves the precision and reliability of FMD analysis compared with the original software algorithm. We demonstrate that this modified open-source software is a robust tool for FMD analysis.

The force drop after transcranial magnetic stimulation (TMS) delivered to the motor cortex during voluntary muscle contractions could inform about muscle relaxation properties. Because of the physiological relation between skeletal muscle fiber-type distribution and size and muscle relaxation, TMS could be a noninvasive index of muscle relaxation in humans. By combining a noninvasive technique to record muscle relaxation in vivo (TMS) with the gold standard technique for muscle tissue sampling (muscle biopsy), we investigated the relation between TMS-induced muscle relaxation in unfatigued and fatigued states, and muscle fiber-type distribution and size. Sixteen participants (7F/9M) volunteered to participate. Maximal knee-extensor voluntary isometric contractions were performed with TMS before and after a 2-min sustained maximal voluntary isometric contraction. Vastus lateralis muscle tissue was obtained separately from the participants' dominant limb. Fiber type I distribution and relative cross-sectional area of fiber type I correlated with TMS-induced muscle relaxation at baseline ( r = 0.67, adjusted P = 0.01; r = 0.74, adjusted P = 0.004, respectively) and normalized TMS-induced muscle relaxation as a percentage of baseline ( r = 0.50, adjusted P = 0.049; r = 0.56, adjusted P = 0.031, respectively). The variance in the normalized peak relaxation rate at baseline (59.8%, P < 0.001) and in the fatigue resistance (23.0%, P = 0.035) were explained by the relative cross-sectional area of fiber type I to total fiber area. Fiber type I proportional area influences TMS-induced muscle relaxation, suggesting TMS as an alternative method to noninvasively inform about skeletal muscle relaxation properties. NEW & NOTEWORTHY Transcranial magnetic stimulation (TMS)-induced muscle relaxation reflects intrinsic muscle contractile properties by interrupting the drive from the central nervous system during voluntary muscle contractions. We showed that fiber type I proportional area influences the TMS-induced muscle relaxation, suggesting that TMS could be used for the noninvasive estimation of muscle relaxation in unfatigued and fatigued human muscles when the feasibility of more direct method to study relaxation properties (i.e., muscle biopsy) is restricted.

Regarding skeletal muscle hypertrophy, resistance training and nutrition, the most often discussed and proposed supplements include proteins. Although, the correct amount, quality, and daily distribution of proteins is of paramount importance for skeletal muscle hypertrophy, there are many other nutritional supplements that can help and support the physiological response of skeletal muscle to resistance training in terms of muscle hypertrophy. A healthy muscle environment and a correct whole muscle metabolism response to the stress of training is a prerequisite for the increase in muscle protein synthesis and, therefore, muscle hypertrophy. In this review, we discuss the role of different nutritional supplements such as carbohydrates, vitamins, minerals, creatine, omega-3, polyphenols, and probiotics as a support and complementary factors to the main supplement i.e., protein. The different mechanisms are discussed in the light of recent evidence., Competing Interests: The authors declare no conflict of interest., (Copyright: © Academy of Physical Education in Katowice.)

Aim: Force expression is characterized by an interplay of biological and molecular determinants that are expected to differentiate males and females in terms of maximal performance. These include muscle characteristics (muscle size, fiber type, contractility), neuromuscular regulation (central and peripheral factors of force expression), and individual genetic factors (miRNAs and gene/protein expression). This research aims to comprehensively assess these physiological variables and their role as determinants of maximal force difference between sexes., Methods: Experimental evaluations include neuromuscular components of isometric contraction, intrinsic muscle characteristics (proteins and fiber type), and some biomarkers associated with muscle function (circulating miRNAs and gut microbiome) in 12 young and healthy males and 12 females., Results: Male strength superiority appears to stem primarily from muscle size while muscle fiber-type distribution plays a crucial role in contractile properties. Moderate-to-strong pooled correlations between these muscle parameters were established with specific circulating miRNAs, as well as muscle and plasma proteins., Conclusion: Muscle size is crucial in explaining the differences in maximal voluntary isometric force generation between males and females with similar fiber type distribution. Potential physiological mechanisms are seen from associations between maximal force, skeletal muscle contractile properties, and biological markers., (© 2024 The Authors. Acta Physiologica published by John Wiley & Sons Ltd on behalf of Scandinavian Physiological Society.)

Purpose: Dragon Boat discipline has become a popular type of physical exercise among women with breast cancer. The present study aims to investigate the effects of Dragon Boat activity on body composition, physical function, and psychosocial aspects (i.e., body appreciation and quality of life [QoL]) in women operated for breast cancer., Methods: Thirty-one women (age, 57.88 ± 7.88 years; BMI, 27.86 ± 6.38 kg·m -2 ) with a previous breast removal surgery were recruited and randomized into two groups: Dragon Boat group (DB, N = 18) or a home-based non-supervised training program (home exercise group; HG, N = 13). All participants underwent body composition, handgrip test, 30-s chair stand test (30CST), 6-min walking test (6MWT), and shoulder mobility measurements at baseline and after 12 weeks of intervention. Participants also filled out the Body Appreciation Scale-2 (BAS-2) and the Short Form Health Survey-12 (SF-12) self-report questionnaires., Results: Dragon Boat activity significantly improved the 30CST (+ 6%, p = .011) and 6MWT performance (+ 30%, p = .011) compared to a home-based non-supervised training program. Moreover, 20% (3/15 women) of women in the DB group obtained a reliable change from pre- to post-intervention in the BAS-2 and in the mental QoL component of the SF-12 (vs 15% and 0% of the HC group). No reliable change emerged for the physical component of the SF-12., Conclusion: Dragon Boat activity is efficient to improve lower limb strength in women operated for breast cancer. Furthermore, Dragon Boat activity emerged to improve body appreciation and mental QoL in some of the women assigned to this activity. Importantly, no adverse events were documented during the intervention., Trial Registration: NCT05206526 (10/02/2022)., (© 2024. The Author(s).)

An elderly patient with upper back pain and hypertension was diagnosed as having spontaneous spinal epidural hematoma (SSEH) after excluding artery dissection. The initial symptoms of SSEH mimic those of artery dissection, and the symptoms of spinal damage frequently appear later. Physicians should, therefore, be mindful of SSEH., Competing Interests: The authors state that they have no conflict of interest., (© 2024 The Authors. Clinical Case Reports published by John Wiley & Sons Ltd.)

Intermittent short-term fasting (ISTF) and ketogenic diets (KDs) exert overlapping but not identical effects on cell metabolism, function, and resilience. Whereas health benefits of KD are largely mediated by the ketone bodies (KBs), ISTF engages additional adaptive physiological responses. KDs act mainly through inhibition of histone deacetylases (HDACs), reduction of oxidative stress, improvement of mitochondria efficiency, and control of inflammation. Mechanisms of action of ISTF include stimulation of autophagy, increased insulin and leptin sensitivity, activation of AMP-activated protein kinase (AMPK), inhibition of the mechanistic target of rapamycin (mTOR) pathway, bolstering mitochondrial resilience, and suppression of oxidative stress and inflammation. Frequent switching between ketogenic and nonketogenic states may optimize health by increasing stress resistance, while also enhancing cell plasticity and functionality., Competing Interests: Declaration of interests The authors have no interests to declare., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background: Bioelectrical impedance analysis (BIA) is a rapid and user-friendly technique for assessing body composition in sports. Currently, no sport-specific predictive equations are available, and the utilization of generalized formulas can introduce systematic bias. The objectives of this study were as follows: (i) to develop and validate new predictive models for estimating fat-free mass (FFM) components in male elite soccer players; (ii) to evaluate the accuracy of existing predictive equations., Methods: A total of 102 male elite soccer players (mean age 24.7 ± 5.7 years), participating in the Italian first league, underwent assessments during the first half of the in-season period and were randomly divided into development and validation groups. Bioelectrical resistance (R) and reactance (Xc), representing the bioimpedance components, were measured using a foot-to-hand BIA device at a single frequency of 50 kHz. Dual-energy X-ray absorptiometry was employed to acquire reference data for FFM, lean soft tissue (LST), and appendicular lean soft tissue (ALST). The validation of the newly developed predictive equations was conducted through regression analysis, Bland-Altman tests, and the area under the curves (AUC) of regression receiver operating characteristic (RROC) curves., Results: Developed models were: FFM = - 7.729 + (body mass × 0.686) + (stature 2 /R × 0.227) + (Xc × 0.086) + (age × 0.058), R 2  = 0.97, Standard error of estimation (SEE) = 1.0 kg; LST = - 8.929 + (body mass × 0.635) + (stature 2 /R × 0.244) + (Xc × 0.093) + (age × 0.048), R 2  = 0.96, SEE = 0.9 kg; ALST = - 24.068 + (body mass × 0.347) + (stature 2 /R × 0.308) + (Xc × 0.152), R 2  = 0.88, SEE = 1.4 kg. Train-test validation, performed on the validation group, revealed that generalized formulas for athletes underestimated all the predicted FFM components (p < 0.01), while the new predictive models showed no mean bias (p > 0.05), with R 2 values ranging from 0.83 to 0.91, and no trend (p > 0.05). The AUC scores of the RROC curves indicated an accuracy of 0.92, 0.92, and 0.74 for FFM, LST, and ALST, respectively., Conclusions: The utilization of generalized predictive equations leads to an underestimation of FFM and ALST in elite soccer players. The newly developed soccer-specific formulas enable valid estimations of body composition while preserving the portability of a field-based method., (© 2023. The Author(s).)

Background: Bioelectrical impedance analysis (BIA) is a technique widely used for estimating body composition and health-related parameters. The technology is relatively simple, quick, and non-invasive, and is currently used globally in diverse settings, including private clinicians' offices, sports and health clubs, and hospitals, and across a spectrum of age, body weight, and disease states. BIA parameters can be used to estimate body composition (fat, fat-free mass, total-body water and its compartments). Moreover, raw measurements including resistance, reactance, phase angle, and impedance vector length can also be used to track health-related markers, including hydration and malnutrition, and disease-prognostic, athletic and general health status. Body composition shows profound variability in association with age, sex, race and ethnicity, geographic ancestry, lifestyle, and health status. To advance understanding of this variability, we propose to develop a large and diverse multi-country dataset of BIA raw measures and derived body components. The aim of this paper is to describe the 'BIA International Database' project and encourage researchers to join the consortium., Methods: The Exercise and Health Laboratory of the Faculty of Human Kinetics, University of Lisbon has agreed to host the database using an online portal. At present, the database contains 277,922 measures from individuals ranging from 11 months to 102 years, along with additional data on these participants., Conclusion: The BIA International Database represents a key resource for research on body composition., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

Insulin signaling often plays a role in the regulation of cancer, including tumor initiation, progression, and response to treatment. In addition, the insulin-regulated PI3K-Akt-mTOR pathway plays an important role in the regulation of islet cell proliferation, and this pathway is hyperactivated in human non-functional pancreatic neuroendocrine tumors (PanNETs). We, therefore, investigated the effect of a very low carbohydrate diet (ketogenic diet) on a mouse model that develops non-functional PanNETs to ask how reduced PI3K-Akt-mTOR signaling might affect the development and progression of non-functional PanNET. We found that this dietary intervention resulted in lower PI3K-Akt-mTOR signaling in islet cells and a significant reduction in PanNET formation and progression. We also found that this treatment had a significant effect on the suppression of pituitary NET development. Furthermore, we found that non-functional PanNET patients with lower blood glucose levels tend to have a better prognosis than patients with higher blood glucose levels. This preclinical study shows that a dietary intervention that results in lower serum insulin levels leads to lower insulin signals within the neuroendocrine cells and has a striking suppressive effect on the development and progression of both pancreatic and pituitary NETs., (© 2023. The Author(s).)

Background & Aims: The bioelectrical impedance vector analysis (BIVA) represents a qualitative analysis of body composition. The vector, defined by resistance (R) and reactance (Xc) standardized by stature, can be evaluated compared to the 50%,75%, and 95% tolerance ellipses representative of the reference populations. The tolerance ellipses for healthy adults have been provided in 1995 and were developed by mixing underage, adult, and elderly subjects, possibly misrepresenting the actual adult population. The current multicentric, cross-sectional study aimed to provide new tolerance ellipses specific for the general adult population and as a secondary aim to present centile curves for the bioelectrical phase angle., Methods: R, Xc, and phase angle were measured in 2137 and 2230 males and females using phase-sensitive foot-to-hand analyzers at 50 kHz. A minimum of 35 subjects were included for each sex and age category from 18 to 65 years., Results: The new mean vectors showed a leftward shift on the R-Xc graph with respect to the former reference values (males: F = 75.3; p < 0.001; females: F = 36.6, p < 0.001). The results provided new 3rd, 5th, 10th, 25th, 50th, 75th, 90th, 95th, and 97th percentile curves for phase angle, identifying time point phases of decrement (males: -0.03° per year at 33.0-51.0 years and -0.05° per year after 51 years; females: -0.03° per year from 37.2 to 57.9 years)., Conclusions: Compared to the original references, the new data are characterized by a different distribution within the R-Xc graph with a higher phase angle. Thirty years after the BIVA invention, the current study presents new tolerance ellipses and phase angle reference values for the adult population., Competing Interests: Conflicts of interest The authors declare that they have no competing interests., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Several factors affect muscle protein synthesis (MPS) in the postabsorptive state. Extreme physical inactivity (e.g., bedrest) may reduce basal MPS, whereas walking may augment basal MPS. We hypothesized that outpatients would have a higher postabsorptive MPS than inpatients. To test this hypothesis, we conducted a retrospective analysis. We compared 152 outpatient participants who arrived at the research site the morning of the MPS assessment with 350 Inpatient participants who had an overnight stay in the hospital unit before the MPS assessment the following morning. We used stable isotopic methods and collected vastus lateralis biopsies ∼2 to 3 h apart to assess mixed MPS. MPS was ∼12% higher ( P < 0.05) for outpatients than inpatients. Within a subset of participants, we discovered that after instruction to limit activity, outpatients ( n = 13) took 800 to 900 steps in the morning to arrive at the unit, seven times more steps than inpatients ( n = 12). We concluded that an overnight stay in the hospital as an inpatient is characterized by reduced morning activity and causes a slight but significant reduction in MPS compared with participants studied as outpatients. Researchers should be aware of physical activity status when designing and interpreting MPS results. NEW & NOTEWORTHY The postabsorptive muscle protein synthesis rate is lower in the morning after an overnight inpatient hospital stay compared with an outpatient visit. Although only a minimal amount of steps was conducted by outpatients (∼900), this was enough to increase postabsorptive muscle protein synthesis rate.

Introduction: Mitochondrial dysfunction is implicated in the metabolic myopathy accompanying peripheral artery disease (PAD) and critical limb ischemia (CLI). Type-2 diabetes mellitus (T2DM) is a major risk factor for PAD development and progression to CLI and may also independently be related to mitochondrial dysfunction. We set out to determine the effect of T2DM in the relationship between CLI and muscle mitochondrial respiratory capacity and coupling control., Methods: We studied CLI patients undergoing revascularization procedures or amputation, and non-CLI patients with or without T2DM of similar age. Mitochondrial respiratory capacity and function were determined in lower limb permeabilized myofibers by high-resolution respirometry., Results: Fourteen CLI patients (65 ± 10y) were stratified into CLI patients with (n = 8) or without (n = 6) T2DM and were compared to non-CLI patients with (n = 18; 69 ± 5y) or without (n = 19; 71 ± 6y) T2DM. Presence of CLI but not T2DM had a marked impact on all mitochondrial respiratory states in skeletal muscle, adjusted for the effects of sex. Leak respiration (State 2, P < 0.025 and State 4 o , P < 0.01), phosphorylating respiration (P < 0.001), and maximal respiration in the uncoupled state (P < 0.001), were all suppressed in CLI patients, independent of T2DM. T2DM had no significant effect on mitochondrial respiratory capacity and function in adults without CLI., Conclusions: Skeletal muscle mitochondrial respiratory capacity was blunted by ∼35% in patients with CLI. T2DM was not associated with muscle oxidative capacity and did not moderate the relationship between muscle mitochondrial respiratory capacity and CLI., (Copyright © 2023. Published by Elsevier Inc.)

The ketogenic diet (KD) is, nowadays, considered an interesting nutritional approach for weight loss and improvement in insulin resistance. Nevertheless, most of the studies available in the literature do not allow a clear distinction between its effects on insulin sensitivity per se, and the effects of weight loss induced by KDs on insulin sensitivity. In this review, we discuss the scientific evidence on the direct and weight loss mediated effects of KDs on glycemic status in humans, describing the KD's biochemical background and the underlying mechanisms.

Resistance training has been proposed as a valid practice to counteract the aging effect on body mass and its components, which can be easily evaluated though the bioelectrical impedance analysis. This study aimed to achieve a systematic review with meta-analysis on the impact of resistance training on bioelectrical proprieties in older adults.A literature review was done in four electronic databases up to 1 January 2022. The inclusion criteria were: (i) participants aged ≥ 60 years; (ii) resistance training lasted ≥ 8 weeks; (iii) measurement of raw bioelectrical parameters in randomized controlled study designs.The outcomes of the trial had to be bioelectrical phase angle (PhA), resistance (R), and reactance (Xc). The methodological quality was assessed using the Rosendal scale.Overall, seven studies with a total of 344 participants were eligible for the analysis. The quality assessment yielded a score of 71.3%. Bioelectrical PhA (0.52 degree [95%CI 0.32, 0.71], p < 0.001) and Xc (3.58 ohms [95%CI 1.97, 5.19], p < 0.001) increased, whereas R decreased (-28.50 ohms [95%CI -41.39, -15.60], p < 0.001) after the resistance training programs.In this meta-analysis, resistance training promoted increases of PhA, which result from an increase in Xc concomitant with a reduction in R. According to the bioimpedance vector analysis, resistance-trained people experienced a beneficial leftward vector displacement, whilst inactivity induced a rightward vector displacement within the R-Xc graph. In future, more sophisticated and rigorous studies that address specific criteria, methods and targeted designs are required to identify which equipment and protocols allow for an optimization of the resistance training effects.Registration code in PROSPERO: CRD42020168057., (© 2022. The Author(s).)

Background: While fear of movement is an important predictor of pain and disability in osteoarthritis (OA), its impact on patients with hip OA remains uncertain. This study aimed to determine whether fear of movement, evaluated by the Tampa Scale for Kinesiophobia (TSK)-11, and pain catastrophizing, evaluated by the Pain Catastrophizing Scale (PCS), were associated with quality of life (QOL) in patients with hip OA., Methods: This cross-sectional study was conducted between November 2017 and December 2018. Ninety-one consecutively enrolled patients with severe hip OA were scheduled for primary unilateral total hip arthroplasty. The EuroQOL-5 Dimensions questionnaire was used to measure general QOL. The Japanese Orthopedic Association Hip Disease Evaluation Questionnaire was used to assess disease-specific QOL. The covariates included age, sex, body mass index (BMI), pain intensity, high pain catastrophizing (PCS ≥ 30), and high kinesiophobia (TSK-11 ≥ 25). Variables were subjected to multivariate analysis using each QOL scale., Results: In multiple regression analysis, pain intensity, high pain catastrophizing, and BMI were independently correlated with the disease-specific QOL scale. High pain catastrophizing, pain intensity, and high kinesiophobia were independently correlated with the general QOL scale., Conclusions: High pain catastrophizing (PCS ≥ 30) was independently associated with disease and general QOL scales. High kinesiophobia (TSK-11 ≥ 25) was independently associated with the general QOL scale in preoperative patients with severe hip OA., (© 2023. The Author(s).)

Because of the biophysical relation between muscle fibre diameter and the propagation velocity of action potentials along the muscle fibres, motor unit conduction velocity could be a non-invasive index of muscle fibre size in humans. However, the relation between motor unit conduction velocity and fibre size has been only assessed indirectly in animal models and in human patients with invasive intramuscular EMG recordings, or it has been mathematically derived from computer simulations. By combining advanced non-invasive techniques to record motor unit activity in vivo, i.e. high-density surface EMG, with the gold standard technique for muscle tissue sampling, i.e. muscle biopsy, here we investigated the relation between the conduction velocity of populations of motor units identified from the biceps brachii muscle, and muscle fibre diameter. We demonstrate the possibility of predicting muscle fibre diameter (R 2  = 0.66) and cross-sectional area (R 2  = 0.65) from conduction velocity estimates with low systematic bias (∼2% and ∼4% respectively) and a relatively low margin of individual error (∼8% and ∼16%, respectively). The proposed neuromuscular interface opens new perspectives in the use of high-density EMG as a non-invasive tool to estimate muscle fibre size without the need of surgical biopsy sampling. The non-invasive nature of high-density surface EMG for the assessment of muscle fibre size may be useful in studies monitoring child development, ageing, space and exercise physiology, although the applicability and validity of the proposed methodology need to be more directly assessed in these specific populations by future studies. KEY POINTS: Because of the biophysical relation between muscle fibre size and the propagation velocity of action potentials along the sarcolemma, motor unit conduction velocity could represent a potential non-invasive candidate for estimating muscle fibre size in vivo. This relation has been previously assessed in animal models and humans with invasive techniques, or it has been mathematically derived from simulations. By combining high-density surface EMG with muscle biopsy, here we explored the relation between the conduction velocity of populations of motor units and muscle fibre size in healthy individuals. Our results confirmed that motor unit conduction velocity can be considered as a novel biomarker of fibre size, which can be adopted to predict muscle fibre diameter and cross-sectional area with low systematic bias and margin of individual error. The proposed neuromuscular interface opens new perspectives in the use of high-density EMG as a non-invasive tool to estimate muscle fibre size without the need of surgical biopsy sampling., (© 2023 The Authors. The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.)

Rigid spinal fusion with instrumentation has been widely applied in treating degenerative spinal disorders and has shown excellent and stable surgical results. However, adjacent segment pathology or implants' loosening could be problematic due to the spine's segmental fusion. Therefore, this study verified a novel concept for posterior stabilization with polyethylene inserts inside a pedicle screw assembly using bone models. We observed that although the gripping capacity of the dynamic pedicle screw system using a tensile and compression tester was less than half that of the rigid pedicle screw system, the flexion-extension moment of the dynamic pedicle screws was significantly lower than that of the rigid pedicle screws. Furthermore, while the bending force of the rigid pedicle screw assembly increased linearly with an increase in the bending angle throughout the test, that of the dynamic pedicle screw assembly also increased linearly until a bending angle of 2.5° was reached. However, this angle decreased at a bending angle of more than 2.5°. Additionally, the fatigue test of 1.0 × 10 6 cycles showed that the pull-out force of the dynamic pedicle screws from two different polyurethane foam blocks was significantly higher than that of the rigid pedicle screws. Therefore, based on our results, we propose that the device can be applied in clinical cases to reduce screw loosening and adjacent segment pathology., (© 2022 Wiley Periodicals LLC.)