Leg Muscle Mass Research Articles

TMG Symmetry and Kinematic Analysis of the Impact of Different Plyometric Programs on Female Athletes’ Lower-Body Muscles

Asymmetries in sports are common and can lead to various issues; however, different training programs can facilitate change. This study aimed to assess the effects of opposing plyometric programs on tensiomyography lateral symmetry (TMG LS)/inter-limb asymmetry in female athletes’ lower-body muscles, alongside kinematic and body composition parameters. Twenty female subjects from basketball, volleyball, and track and field (sprinting disciplines) were divided into two experimental groups (n = 10 each). Two six-week plyometric programs (two sessions/week) were implemented: the first program (E1) focused on eccentric exercises, depth landings, while the second (E2) emphasized concentric exercises, squat jumps. TMG assessed LS in six muscles: vastus lateralis, vastus medialis, biceps femoris, semitendinosus, gastrocnemius lateralis, and gastrocnemius medialis. A kinematic analysis of the countermovement jump (CMJ) and body composition was conducted using “Kinovea; Version 0.9.4” software and InBody 770, respectively. The results showed significant increases in LS percentages (E1—VL 9.9%, BF 18.0%, GM 10.6% and E2—BF 22.5%, p < 0.05), and a significant large effect in E1 for VL, and in E2 for BF, p < 0.01). They also showed that E1 had a significant effect on VL, and that E2 had a significant large effect on BF (p < 0.01). E1 also led to increased lean muscle mass in both legs (left: 1.88%, right: 2.74%) and decreased BMIs (−0.4, p < 0.05). Both programs improved LS, with E1 enhancing muscle mass and lower-body positioning in CMJ. We recommend future studies use varied jump tests, incorporate 3D kinematic analysis, include male subjects, and examine more muscles to enhance TMG LS analysis.

Evaluation of waist-to-calf ratio as a diagnostic tool for sarcopenic obesity: a cross-sectional study from a geriatric outpatient clinic.

Proponents argue that a high waist-to-calf ratio (WCR) may indicate an imbalance between muscle and fat in the body, making it a potential predictor for sarcopenic obesity (SO). The WCR is a new index incorporating both measurements, providing a reliable approach for assessing the imbalance between abdominal fat and leg muscle mass. The present study aimed to examine the association of WCR with SO and reveal the predictive effect of SO in community-dwelling older adults. The study population was composed of 234 geriatric outpatients with obesity. WCR was calculated by dividing the waist circumference (in cm) by the calf circumference (in cm). SO was defined according to the ESPEN and EASO Consensus Statement. The mean age was 72.7 ± 5.8years, and 78.7% (n = 175) were female. Eighty-one patients (34.6%) were considered as sarcopenic obese. The WCR was 3.04 [Interquartile range (IQR), 2.88-3.32] in the sarcopenic obese group, and in the nonsarcopenic obese group, it was 2.82 [IQR, 2.7-3.0] (p < 0.001). Independent of age, sex, nutritional and frailty status WCR was associated with SO (OR 12.7, 95% CI 4.0-40.1 and p < 0.001). The cut-off value of WCR for SO was calculated as 2.94 with 72.8% sensitivity and 67.3% specificity (Area Under Curve: 0.72 and Positive likelihood ratio: 2.23, p < 0.001). WCR, a simple and accessible method, indicates promise as a possible and potential diagnostic tool for SO in community-dwelling older adults.

Differential impacts of fat and muscle mass on cardiovascular and non-cardiovascular mortality in individuals with type 2 diabetes.

The distribution of fat and muscle mass in different regions of the body can reflect different pathways to mortality in individuals with diabetes. Therefore, we investigated the associations between whole-body and regional body fat and muscle mass with cardiovascular disease (CVD) and non-CVD mortality in type 2 diabetes (T2D). Within the National Health and Nutrition Examination Survey 1999-2006, 1417 adults aged ≥50years with T2D were selected. Dual-energy X-ray absorptiometry was used to derive whole-body, trunk, arm, and leg fat mass and muscle mass indices (FMI and MMI). Mortality data until 31 December 2019 were retrieved from the National Death Index. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated from Cox proportional hazard models. A total of 1417 participants were included in this study (weighted mean age [standard error]: 63.7 [0.3] years; 50.5% female). Over a median follow-up of 13.6years, 797 deaths were recorded (371 CVD-related and 426 non-CVD deaths). Higher FMI in the arm was associated with increased risk of non-CVD mortality (fourth quartile [Q4] vs. first quartile [Q1]: HR 1.82 [95% CI 1.13-2.94]), whereas higher FMI in the trunk or leg was not significantly associated with CVD or non-CVD mortality. Conversely, higher arm MMI was associated with a lower risk of both CVD (Q4 vs. Q1: HR 0.51 [95% CI 0.33-0.81]) and non-CVD (Q4 vs. Q1: HR 0.56 [95% CI 0.33-0.94]) mortality. There was a significant interaction between smoking status and arm FMI on non-CVD mortality (P for interaction=0.007). Higher arm FMI was associated with a higher risk of non-CVD mortality among current or former smokers (Q4 vs. Q1: HR 2.67 [95% CI 1.46-4.88]) but not non-smokers (Q4 vs. Q1: HR 0.85 [95% CI 0.49-1.47]). Fat mass and muscle mass, especially in the arm, are differently associated with CVD and non-CVD mortality in people with T2D. Our findings underscore the predictive value of body compositions in the arm in forecasting mortality among older adults with T2D.

Accuracy of a portable lower-limb muscle strength measuring device with a training function.

[Purpose] Quadriceps muscle strength is essential for daily living activities. Therefore, we developed a compact and simple lower limb muscle strength measuring device (LocomoScan [LCS]). This study aimed to compare LCS with other instruments to analyze its simplicity, reproducibility, and accuracy. [Participants and Methods] One hundred and four healthy university students (56 males and 48 females) were included in the study. The knee extension force was measured using LCS, and the knee extension torque was measured using other devices (Cybex). In addition, lower leg muscle mass was measured using a body composition meter. The reproducibility of LCS and the correlation between the knee extension torque and lower leg muscle mass were evaluated. [Results] The measurement reproducibility of LCS was significantly higher. The knee extension force confirmed the proportional relative reliability of Cybex with knee extension torque. A relationship between knee extension force and lower limb muscle mass was also observed, indicating that muscle mass cannot be estimated as muscle strength. [Conclusion] The high reproducibility of the knee extension force measurement using LCS demonstrates its potential as a portable alternative instrument for muscle strength measurement in clinical practice. Therefore, LCS device is a simple and effective tool for assessing muscle strength.

Targeted activation of Nrf2 prevents losses in leg muscle mass and strength during 2 weeks of immobilization in young adults

Introduction: Leg immobilization results in substantial losses in muscle mass and strength. Strategies aimed at minimizing these losses have proven largely ineffective. Elevated oxidative stress has been identified as a potential mechanism contributing to these losses. Therefore, we tested the hypothesis that PB125, an activator of Nrf2 (the master regulator of the endogenous antioxidant system), and MitoQ, a mitochondrial-targeted antioxidant, would decrease the deleterious effects of limb immobilization on muscle mass and strength. Methods: A double-blind, placebo-controlled trial was performed in a cohort of twenty young healthy adults (6M/14F, Age: 28±7 y; Height: 169±7 cm; Mass: 70±14 kg). Participants were randomized into either placebo (n=7), PB125 (n=6), or MitoQ (n=7). Supplementation and measures of physical activity using an accelerometer began 2 weeks prior to single leg immobilization and continued through 2 weeks of immobilization. Knee extensor muscle strength was tested before and after immobilization using isometric maximal voluntary contractions (MVC) and isokinetic contractions (120 and 60 degrees/s). Muscle mass was determined by MRI, and thigh lean muscle volume from image slices between the patellar tendon and gluteal muscle were assessed. Results: Physical activity, measured by steps per day, decreased by 55-65% during limb immobilization for all groups (p &lt;0.05). Isometric muscle strength was significantly decreased following placebo (145±40 to 119±27 kg; p &lt;0.05) and MitoQ (148±36 to 118±36 kg; p &lt;0.05), but not PB125 (140±55 to 144±71 kg, p=0.7). Similarly, isokinetic muscle strength measured at 120 and 60 degrees/s was significantly decreased in placebo and MitoQ but preserved with PB125. Lean muscle volume in the immobilized limb significantly decreased by ~4% in placebo (p&lt;0.05) and MitoQ (p&lt;0.05) but was preserved with PB125 (p =0.55). Conclusions: Targeted activation of Nrf2 with PB125 preserved muscle mass and strength following 2 weeks of leg immobilization. In contrast, both placebo and MitoQ had no impact on immobilization-induced losses in muscle mass and strength. These findings provide novel evidence that targeting Nrf2 offsets the detrimental skeletal muscle effects of limb immobilization in young, healthy individuals. NIH-R01HL142603 and VA Merit-I01CX001999. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Sex differences in muscle morphology between male and female sprinters.

There is a marked difference between males and females in sprint running performance, yet a comprehensive investigation of sex differences in the muscle morphology of sprinters, which could explain the performance differences, remains to be completed. This study compared muscle volumes of 23 individual leg muscles and 5 functional muscle groups, assessed with 3 T magnetic resonance imaging, between male (n = 31) and female (n = 22) sprinters, as well as subgroups of elite males (EM, n = 5), elite females (EF, n = 5), and performance-matched (to elite females) males (PMMEF, n = 6). Differences in muscle volume distribution between EM, EF, and unathletic male (UM) controls were also assessed. For the full cohorts, male sprinters were more muscular than their female counterparts, but the differences were nonuniform and anatomically variable, with the largest differences in the hip extensors and flexors. However, among elite sprinters the sex differences in the volume of the functional muscle groups were almost uniform (absolute volume +47-53%), and the muscle volume distribution of EM was more similar to EF than to UM (P < 0.039). For PMMEF, relative hip extensor volume, but not stature or percent body fat, differentiated for performance (PMMEF and EF < EM) rather than sex. In conclusion, although the full cohorts of sprinters showed a marked sex difference in the amount and distribution of muscle mass, elite sprinters appeared to be selected for a common muscle distribution phenotype that for these elite subgroups was a stronger effect than that of sex. Relative hip extensor muscle volume, rather than stature, percent body fat, or total relative muscle volume, appeared to be the primary determinant of the sex difference in performance.NEW & NOTEWORTHY We present novel evidence suggesting muscle volume, specifically relative hip extensor volume, may be a primary deterministic variable for the sex difference in sprint performance, such that with matched sprint times, male and female sprinters may be expected to have equivalent muscle morphology. We highlight striking similarities in distribution of leg muscle mass between elite male and female sprinters and provide evidence for the existence of a muscular distribution phenotype specific to elite sprinters, irrespective of sex.

Reduced Muscle Mass and Muscle Quality in Patients with Intermittent Claudication due to Peripheral Artery Disease

ObjectivePeripheral arterial disease (PAD) is associated with reduced muscle mass and quality, but the effects of leg ischemia caused by PAD on muscle quality remain poorly understood. The purpose of this study was to evaluate leg muscle mass and muscle quality in patients with intermittent claudication due to PAD using bioelectrical impedance analysis (BIA). MethodsOne hundred forty-one patients with intermittent claudication due to PAD who visited Tokyo Medical University Hospital from April 2019 to April 2020 were retrospectively analyzed. Leg ischemia was assessed using ankle-brachial index (ABI). The skeletal muscle mass (SMM) assessed leg muscle mass, while the phase angle (PhA) assessed leg muscle quality using BIA. ResultsA total of 282 legs in 141 patients were included in the analysis. Leg PhA and SMM showed a decreasing trend according to the severity of leg ischemia (borderline/no ischemia: 2.80 ± 0.50 kg/m2, 4.38 ± 0.94°; mild ischemia: 2.83 ± 0.49 kg/m2, 4.33 ± 1.03°; moderate/severe ischemia: 2.50 ± 0.40 kg/m2, 3.89 ± 0. 88°; p<0.001 and p=0.020, respectively). The ABI was moderately correlated with leg SMM (B=0.347, β=0.134, p<0.001) and leg PhA (B=0.577, β=0.111, p=0.013) after adjustment for all significant covariates. Leg PhA was moderately correlated with leg SMM (r = 0.318, p < 0.001). ConclusionsLeg ischemia, especially when moderate or severe, has an adverse effect on both muscle mass and quality in the lower extremities and is associated with skeletal muscle myopathy.

The amount of lower leg muscle and physical activity in patients with postural tachycardia syndrome

Background: Resistance training for leg muscles is recommended for patients with postural tachycardia syndrome (POTS). However, no study has characterized the relationships between orthostatic symptoms, heart rate (HR) increase, and the mass of the lower leg muscle in patients with POTS. We sought to determine the relationships between the mass of the lower leg muscle, HR increase during the head-up tilt (HUT) test, and orthostatic symptoms in patients with POTS.Methods: We prospectively enrolled 42 patients with POTS who were older than 16 years. The muscle mass was estimated using bioelectrical impedance analysis. We used the International Physical Activity Questionnaire-Short Form to measure self-reported physical activity. All patients were asked to complete the Korean version of the Orthostatic Grading Scale (KOGS).Results: The HR increased during the HUT test by 38.7±7.88 beats/minutes. Both the HR increase during the HUT test and the total KOGS score were negatively correlated with the total metabolic equivalent of the task. The leg circumference and muscle mass were not correlated with the HR increase during the HUT test or the KOGS score.Conclusions: The leg circumference and muscle mass were not related to orthostatic symptoms in patients with POTS. Cardiac remodeling or blood volume increase may be responsible for improvement in POTS after physical activity.

Unveiling the muscle-brain axis: A bidirectional mendelian randomization study investigating the causal relationship between sarcopenia-related traits and brain aging

BackgroundObservational studies suggest an association between sarcopenia-related traits and brain aging, but whether this association reflects a causal relationship remains unclear. This study aims to employ Mendelian randomization (MR) methods to investigate the causal impact of sarcopenia-related traits on brain aging. MethodsThis study presents a comprehensive analysis of genome-wide association study (GWAS) summary data associated with sarcopenia-related traits. The data were derived from a large-scale cohort, encompassing measures such as grip strength, lean body mass, and walking pace. Measurements of brain aging were obtained from neuroimaging genetics, utilizing meta-analysis (ENIGMA) to combine magnetic resonance imaging (MRI) data from 33,992 participants. The primary methodology employed in this analysis was the inverse-variance-weighted method (IVW). Additionally, sensitivity analyses were conducted, to assess heterogeneity and pleiotropy. ResultAppendicular lean mass(ALM) is negatively correlated with Pallidum aging; Whole body fat-free mass shows a negative correlation with Amygdala aging; Leg fat-free mass (left) and Leg fat-free mass (right) are negatively correlated with Pallidum aging; Usual walking pace is positively correlated with Nucleus Accumbens aging. Cerebellum WM aging is negatively correlated with Leg fat-free mass (left) and Leg fat-free mass (right); Hippocampus aging is negatively correlated with Hand grip strength (left) and Hand grip strength (right). Ventricles aging is positively correlated with Usual walking pace; Nucleus Accumbens aging is positively correlated with Leg fat-free mass (left) and Leg fat-free mass (right); Putamen aging is positively correlated with ALM. ConclusionOur study confirms that reduced muscle mass speeds up brain aging. Walking too fast raises the risk of brain aging, while maintaining or increasing appendicular lean mass, overall muscle mass, and muscle mass in both legs lowers the risk of brain aging.

Proteomic Profiling of Muscular Adaptations to Short-Term Concentric Versus Eccentric Exercise Training in Humans

The molecular mechanisms underlying muscular adaptations to concentric (CON) and eccentric (ECC) exercise training have been extensively explored. However, most previous studies have focused on specifically selected proteins, thus, unable to provide a comprehensive protein profile and potentially missing the crucial mechanisms underlying muscular adaptation to exercise training. We herein aimed to investigate proteomic profiles of human skeletal muscle in response to short-term resistance training. Twenty young males were randomly and evenly assigned to two groups to complete a 4-week either ECC or CON training program. Measurements of body composition and physiological function of the quadriceps femoris were conducted both before and after the training. Muscle biopsies from the vastus lateralis of randomly selected participants (five in ECC and four in CON) of both before and after the training were analyzed using the liquid-chromatography tandem mass spectrometry in combination with bioinformatics analysis. Neither group presented a significant difference in body composition or leg muscle mass; however, muscle peak torque, total work, and maximal voluntary contraction were significantly increased after the training in both groups. Proteomics analysis revealed 122 differentially abundant proteins (DAPs; p value < 0.05 & fold change >1.5 or <0.67) in ECC, of which the increased DAPs were mainly related to skeletal muscle contraction and cytoskeleton and enriched specifically in the pentose phosphate pathway, extracellular matrix–receptor interaction, and PI3K−Akt signaling pathway, whereas the decreased DAPs were associated with the mitochondrial respiratory chain. One hundred one DAPs were identified in CON, of which the increased DAPs were primarily involved in translation/protein synthesis and the mitochondria respiratory, whereas the decreased DAPs were related to metabolic processes, cytoskeleton, and de-ubiquitination. In conclusion, the 4-week CON and ECC training resulted in distinctly different proteomic profiles, especially in proteins related to muscular structure and metabolism.

Association between Osteoporosis and Skeletal Muscle Mass in Men.

Cross-sectional study. This cross-sectional study aimed to investigate the risk factors for osteoporosis in men by assessing bone mineral density (BMD), skeletal muscle mass, body fat mass, grip strength, and advanced glycation end products (AGEs). Fewer studies have reported the correlation between BMD and skeletal muscle mass in women. Moreover, a few studies have examined the relationship between osteoporosis and skeletal muscle mass. This study included 99 men (mean age, 74.9 years; range, 28-93 years) who visited Qiball Clinic for BMD and body composition examinations. The osteoporosis group consisted of 24 patients (mean age, 72.5 years; range, 44-92 years), and the control group consisted of 75 individuals (mean age, 74.9 years; range, 28-93 years). Whole-body skeletal muscle mass was measured using a bioelectrical impedance analyzer. BMD was measured by dual X-ray absorptiometry. Skin autofluorescence (SAF), a marker of dermal AGE accumulation, was measured using a spectroscope. Osteoporosis was defined as a bone density T score of -2.5 or less. Physical findings, skeletal muscle mass, BMD, grip strength, and SAF were compared between the osteoporosis and control groups. The osteoporosis group had significantly lower trunk muscle mass (23.1 kg vs. 24.9 kg), lower leg muscle mass (14.4 kg vs. 13.0 kg), and skeletal mass index (7.1 kg/m2 vs. 6.7 kg/m2) than the control group (all p<0.05). Lower limb muscle mass was identified as a risk factor for osteoporosis in men (odds ratio, 0.64; p=0.03). Conservative treatment of osteoporosis in men will require an effective approach that facilitates the maintenance or strengthening of skeletal muscle mass, including exercise therapy with a focus on lower extremities and nutritional supplementation.

A Genotype-Phenotype Model for Predicting Resistance Training Effects on Leg Press Performance.

This study develops a comprehensive genotype-phenotype model for predicting the effects of resistance training on leg press performance. A cohort of physically inactive adults (N=193) underwent 12 weeks of resistance training, and measurements of maximum isokinetic leg press peak force, muscle mass, and thickness were taken before and after the intervention. Whole-genome genotyping was performed, and genome-wide association analysis identified 85 novel SNPs significantly associated with changes in leg press strength after training. A prediction model was constructed using stepwise linear regression, incorporating seven lead SNPs that explained 40.4% of the training effect variance. The polygenic score showed a significant positive correlation with changes in leg press strength. By integrating genomic markers and phenotypic indicators, the comprehensive prediction model explained 75.4% of the variance in the training effect. Additionally, five SNPs were found to potentially impact muscle contraction, metabolism, growth, and development through their association with REACTOME pathways. Individual responses to resistance training varied, with changes in leg press strength ranging from -55.83% to 151.20%. The study highlights the importance of genetic factors in predicting training outcomes and provides insights into the potential biological functions underlying resistance training effects. The comprehensive model offers valuable guidance for personalized fitness programs based on individual genetic profiles and phenotypic characteristics.

2019 Association of Bradykinin receptor 2 variants with physical performance and muscle mass: findings from the LACE sarcopenia trial

Abstract Introduction The kinin-kallikrein system has been implicated in muscle performance: bradykinin promotes glucose uptake and blood flow in muscle through bradykinin receptor 2 (BDKRB2). BDKRB2 variants include rs1799722 and rs5810761, where the T and -9 alleles respectively have associated with increased transcriptional rates and were overrepresented in endurance athletes. However, these variants have rarely been studied among older people or those with sarcopenia. Methods The Leucine and ACE inhibitor (ACE) trial enrolled 145 participants aged ≥70 years with low grip strength and low gait speed. Participants’ blood samples had DNA extracted and were genotyped for rs179972 using TaqMan and rs5810761 by amplification through Hotstar Taq (and visualised through 4% agarose gel electrophoresis). The differences in genotypes for each variant against physical performance measures (e.g. six-minute walk distance [6MWD]) was calculated using t-tests or Mann-Whitney tests where appropriate. Genotypes were also tested for Hardy-Weinberg equilibrium (HWE) using Chi-squared test. Results Data from 136 individuals were included in the analysis. For rs1799722, the genotype frequency (TT: 17, CC: 48, CT: 71) remained in HWE (p=0.248). No difference between TT and CC/CT group was seen for 6MWD, grip strength or SPPB. Among men, the TT genotype had greater 6MWD compared to CC/CT (400m vs 312m, p=0.007), and also greater leg muscle mass (17.6kg vs 15.3kg, p =0.005), but no difference was noted in women. For rs5810761, the genotype frequency (-9-9: 31, +9+9: 43, -9+9: 60) also remained in HWE (p=0.269). No difference between -9-9 and +9+9/+9-9 was seen for 6MWD, grip strength or SPPB. In men, but not women, -9-9 genotype had reduced arm fat baseline (1.85kg vs 2.72kg; p=0.005). Conclusion Among men, the TT genotype was associated with longer 6MW distance and higher leg muscle mass. The -9-9 genotype was associated with lower regional fat mass in men.

Effect of multicomponent intervention on malnutrition in older adults: A multicenter randomized clinical trial

Background & aimsMalnutrition is a significant geriatric syndrome (GS) prevalent in older adults and seriously affects patient prognosis and quality of life. We assessed the impact of the multicomponent intervention of health education, dietary advice, and exercise with oral nutritional supplementation (ONS) on nutritional status, body composition, physical functions, and quality of life. MethodsThis multicenter randomized clinical trial (RCT) was performed from April 2021 to April 2022. The intervention lasted for 12 weeks, and 99 older adults with malnutrition or at risk of malnutrition were enrolled in six nursing homes. All participants were randomly assigned to the control (health education plus standard diet plus exercise) or research (health education plus standard diet plus exercise plus ONS) group. The research group consumed ONS (244 kcal, 9.8g protein, and 9.6g fat per time) twice a day between meals. The primary outcomes were changes in the nutritional status and body composition from baseline to 12 weeks. The secondary outcomes were changes in physical function, quality of life and nutritional associated other blood markers. ResultsFor primary outcomes, after 12 weeks, body weight increased similarly in both treatment arms (time × treatment effect, P>0.05). There were no between-group differences in body mass index (BMI) or mini nutritional assessment tool-short form (MNA-SF) scores (time × treatment effects, P>0.05). The MNA-SF score from 11.0 (10.5, 12.0) to 13.0 (11.0, 13.0) in the research group and from 11.0 (10.0, 12.0) to 12.0 (11.0, 13.0) in the control group (both P<0.05). There were no between-group differences in the skeletal muscle mass index (SMI), fat-free mass index (FFMI), appendicular skeletal muscle mass (ASMM), fat mass (FAT), or leg muscle mass (LMM) (time × treatment effects, P>0.05). Both groups showed similar and highly significant increases in SMI, FFMI, and LMM after (P<0.05). The research group showed an increase in fat-free mass(FFM) and ASMM and a decrease in the percent of body fat (PBF) and waist circumference (WC) (P<0.05).For secondary outcomes, There were no between-group differences in grip strength, short physical performance battery (SPPB), 6-min walking distance (6MWD), activities of daily living (ADL), instrumental activities of daily living (IADL), frailty status (FRAIL), mini-mental state examination (MMSE), Tinetti, geriatric depression scale-15 (GDS-15), or 12-item short form survey (SF-12) (time × treatment effects, P>0.05). Although there was no significant difference, the 6MWD changed differentially between the two treatment arms during the study period in favor of the research group. Although not significant, SF-12 scores improved after 12 weeks in both groups. No between-group differences were observed in prealbumin (PRE), c-reactive protein (CRP), vitamin D (VIT-D), insulin-like growth factor 1 (IGF-1), alanine transaminase (ALT), aspartate aminotransferase (AST), serum creatinine (Scr), interleukin-6 (IL-6), interleukin-10 (IL-10), tumor necrosis factor-α (TNF-α), insulin, and adiponectin levels (time × treatment effects, P>0.05). Insulin and adiponectin levels were significantly higher in the control group (P<0.05). ConclusionThe twelve-week multicomponent intervention improved the nutritional status of older people in China at risk of malnutrition. ONS may enhance the effects of exercise on muscle mass.This clinical trial was registered (https://www.clinicaltrials.gov). The trial number is ChiCTR2000040343.

Association of bradykinin receptor 2 (BDKRB2) variants with physical performance and muscle mass: Findings from the LACE sarcopenia trial.

Understanding genetic contributors to sarcopenia (age-related loss of muscle strength and mass) is key to finding effective therapies. Variants of the bradykinin receptor 2 (BDKRB2) have been linked to athletic and muscle performance. The rs1799722-9 and rs5810761 T alleles have been shown to be overrepresented in endurance athletes, possibly due to increased transcriptional rates of the receptor. These variants have been rarely studied in older people or people with sarcopenia. We performed a post hoc sub-study of the Leucine and ACE (LACE) inhibitor trial, which enrolled 145 participants aged ≥70 years with low grip strength and low gait speed. Participants' blood samples were genotyped for rs179972 using TaqMan and rs5810761 by amplification through Hotstar Taq. Genotypes were compared with outcomes of physical performance and body composition measures. Data from 136 individuals were included in the analysis. For rs1799722 the genotype frequency (TT: 17, CC: 48, CT: 71) remained in Hardy-Weinberg Equilibrium (HWE p = 0.248). There was no difference between the genotypes for six-Minute Walk Distance (6MWD) or Short Physical Performance Battery (SPPB). Men with the TT genotype had a significantly greater 6MWD than other genotypes (TT 400m vs CT 310m vs CC 314m, p = 0.027), and greater leg muscle mass (TT 17.59kg vs CT 15.04kg vs CC 15.65kg, p = 0.007). For rs5810761, the genotype frequency (-9-9: 31, +9+9: 43, -9+9: 60) remained in HWE (p = 0.269). The +9+9 genotype was associated with a significant change in SPPB score at 12 months (-9-9 0 vs -9+9 0 vs +9+9-1, p<0.001), suggesting an improvement. In men, the -9-9 genotype was associated with lower arm fat (-9-9 2.39kg vs -9+9 2.72kg vs +9+9 2.76kg, p = 0.019). In men, the rs1799722 TT genotype was associated with longer 6MWD and greater leg muscle mass, while the rs5810761 -9-9 genotype was associated with lower arm fat mass.

The Correlation Between Leg Muscle Mass Index and Non-Alcoholic Fatty Liver Disease in Patients with Type 2 Diabetes Mellitus.

To analyze the relationship between leg skeletal muscle mass index (LSMI) and non-alcoholic fatty liver disease (NAFLD) in patients with type 2 diabetes mellitus (T2DM) and the ability of LSMI to predict NAFLD. Two hundred patients with T2DM and NAFLD treated at Changzhou Second People's Hospital Affiliated with Nanjing Medical University and the National Metabolic Management Center from June 2022 to June 2023 were divided into four LSMI quartiles. The clinical information from the four patient groups was compared, and the relationship between type 2 diabetes and LSMI and NAFLD was examined. We used receiver operating characteristic curves to determine how well the LSMI predicts NAFLD in T2DM. The lowest quartile (Q1) had a higher prevalence of NAFLD than group Q4 (P < 0.05). LSMI was negatively associated with body mass index, LS, CAP, and other markers (P < 0.05). Receiver operating characteristic curve analysis LSMI predicted NAFLD with an ideal critical value of 0.64 and an area under the curve of 70.9%. The combined predictive value of the LSMI and the appendicular skeletal muscle mass index was more significant. Reduced LSMI is associated with NAFLD.

Analysis of anthropometric and physical performance variables in U-17 soccer players

IntroductionSoccer is considered a multifaceted collective sport, and to reach an elevated level, players must have moderate to high power, good agility, joint flexibility and muscle development. Also, players must be able to generate high torques during fast movements, which implies the development of different capacities, understood as multifactorial preparation. The objective was to analyse the effects of training (aerobic and continuous) on the leg power, fatigue levels, speed, agility, body fat, muscle mass and bone mass of these players.MethodsSeventy-two soccer players, male and under 17, from 4 teams participated. The teams performed 3 times a week training sessions of about 60–90 min each. Informed consent requests were given to their parents for authorisation to participate in this investigation. Data was collected in two different time points, about ten months apart. Specific tests were performed for each variable: the vertical jump with Bosco System for leg power, the T-Test for agility, the linear sprint test for speed and the RAST test for fatigue levels. A precision Tanita scale was used for the anthropometric tests such as body fat, muscle mass and bone mass. Statistical procedures were applied through the Wilcoxon test to compare the two time points of evaluation.ResultsImprovements were found between evaluations regarding the level of anthropometric and physical fitness variables.ConclusionsThe implemented training improved all the analysed variables with significant statistical values for leg power, speed, bone mass, muscle mass and fat mass.

Vascular dysfunction and the age-related decline in critical power.

Ageing results in lower exercise tolerance, manifested as decreased critical power (CP). We examined whether the age-related decrease in CP occurs independently of changes in muscle mass and whether it is related to impaired vascular function. Ten older (63.1±2.5 years) and 10 younger (24.4±4.0 years) physically active volunteers participated. Physical activity was measured with accelerometry. Leg muscle mass was quantified with dual X-ray absorptiometry. The CP and maximum power during a graded exercise test (PGXT ) of single-leg knee-extension exercise were determined over the course of four visits. During a fifth visit, vascular function of the leg was assessed with passive leg movement (PLM) hyperaemia and leg blood flow and vascular conductance during knee-extension exercise at 10W, 20W, slightly below CP (90% CP) and PGXT . Despite not differing in leg lean mass (P=0.901) and physical activity (e.g., steps per day, P=0.735), older subjects had ∼30% lower mass-specific CP (old=3.20±0.94Wkg-1 vs. young=4.60±0.87Wkg-1 ; P<0.001). The PLM-induced hyperaemia and leg blood flow and/or conductance were blunted in the old at 20W, 90% CP and PGXT (P<0.05). When normalized for leg muscle mass, CP was strongly correlated with PLM-induced hyperaemia (R2 =0.52; P<0.001) and vascular conductance during knee-extension exercise at 20W (R2 =0.34; P=0.014) and 90% CP (R2 =0.39; P=0.004). In conclusion, the age-related decline in CP is not only an issue of muscle quantity, but also of impaired muscle quality that corresponds to impaired vascular function.

Inhaled beta2 -agonist, formoterol, enhances intense exercise performance, and sprint ability in elite cyclists.

Many athletes use long-acting beta2 -agonist formoterol in treatment of asthma. However, studies in non-athlete cohorts demonstrate that inhaled formoterol can enhance sprint performance calling into question whether its use in competitive sports should be restricted. We investigated whether formoterol at upper recommended inhaled doses (54 μg) would enhance sprint ability and intense exercise performance in elite cyclists. Twenty-one male cyclists (V̇O2max : 70.4 ± 4.3 mL × min-1 × kg-1 , mean ± SD) completed two 6-s all-out sprints followed by 4-min all-out cycling after inhaling either 54 μg formoterol or placebo. We also assessed cyclists' leg muscle mass by dual-energy X-ray absorptiometry and muscle fiber type distribution of vastus lateralis biopsies. Peak and mean power output during the 6-s sprint was 32 W (95% CI, 19-44 W, p < 0.001) and 36 W (95% CI, 24-48 W, p < 0.001) higher with formoterol than placebo, corresponding to an enhancing effect of around 3%. Power output during 4-min all-out cycling was 9 W (95% CI, 2-16 W, p = 0.01) greater with formoterol than placebo, corresponding to an enhancing effect of 2.3%. Performance changes in response to formoterol were unrelated to cyclists' VO2max and leg lean mass, whereas muscle fiber Type I distribution correlated with change in sprinting peak power in response to formoterol (r2 = 0.314, p = 0.012). Our findings demonstrate that an inhaled one-off dose of 54 μg formoterol has a performance-enhancing potential on sprint ability and short intense performance in elite male cyclists, which is irrespective of training status but partly related to muscle fiber type distribution for sprint ability.

MOTS-c Serum Concentration Positively Correlates with Lower-Body Muscle Strength and Is Not Related to Maximal Oxygen Uptake-A Preliminary Study.

The mitochondrial open reading frame of 12S rRNA-c (MOTS-c) is a mitochondrial-derived peptide that regulates the nuclear genome during stressful conditions such as hypoxia, which is typical of exercise and training. We aim to mainly investigate the relationship between serum MOTS-c concentration and muscle strength parameters measured during the countermovement jump test with oxygen consumption (VO2) measured during the cardiopulmonary exercise test to exhaustion. Physically active healthy volunteers (17 male, three female, median age 30 years), not involved in any regular exercise program or participating in any sports competitions, performed five consecutive countermovement jump tests and cardiopulmonary exercise tests until maximal exhaustion and underwent a body composition assessment by means of bioelectrical impedance analysis, and had serum MOTS-c concentration measured at rest. Serum MOTS-c concentration was positively correlated with the average power and average and maximal force of the jumps, both overall muscle mass and leg muscle mass, but not with body fat percentage. There was no correlation with peak VO2. A higher serum MOTS-c concentration is associated with greater muscle mass, force, and power generated during jumping in healthy individuals but not exercise capacity reflected by peak VO2. More studies are needed to better understand the physiological and clinical values of these findings and why MOTS-c is better associated with measures of muscle strength and not endurance in physically active people.