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PubMed2026

Comparative effects of 12-week resistance training on unstable and stable surfaces on muscle stiffness, muscle co-activation, and balance in older patients with knee osteoarthritis.

OBJECTIVE: This randomized trial compared the effects of unstable resistance training (URT), involving resistance exercises on unstable surfaces, and stable resistance training (SRT), performed on stable surfaces, on muscle stiffness, co-activation, and balance in older adults with knee osteoarthritis (KOA). We hypothesized that URT would yield greater improvements by enhancing neuromuscular adaptability. METHODS: Fifty patients with KOA were randomly assigned to the URT group (n = 25) or the SRT group (n = 25). After attrition, 46 participants (URT: n = 23; SRT: n = 23) completed the intervention and were included in the final analysis. Both groups completed a 12-week supervised lower-limb resistance training program (3 sessions/week) consisting of 10 exercises performed under either unstable or stable support conditions. RESULTS: After 12 weeks of intervention, both groups showed significant reductions in pain intensity (p < 0.001). However, compared with the SRT group, the URT group demonstrated significantly greater reductions in quadriceps stiffness (p < 0.05), selected hamstring stiffness outcomes (p < 0.05), and quadriceps-hamstring co-activation (p < 0.001), alongside superior improvements in both dynamic balance and static balance (all p < 0.05). CONCLUSION: While both training modalities are effective for pain relief, URT elicited greater improvements in balance-related performance and neuromuscular-mechanical outcomes than SRT in older adults with KOA. These findings suggest that incorporating unstable support conditions into resistance training may provide additional rehabilitation benefits for this population.

Humans↗

PubMed2026

Muscular fiber properties and multi-omics investigation of larval and adult locomotor muscle in Microhyla fissipes.

During metamorphosis, Microhyla fissipes undergoes a critical transition from an aquatic to a terrestrial lifestyle, accompanied by significant remodeling of skeletal muscle. Notably, larval tail muscle degenerates, while adult hindlimb muscle develops. However, the molecular mechanisms that orchestrate these muscle type-specific adaptations to the changing environment remain unclear. In this study, histological observation, transcriptomics, and metabolomics were integrated to compare locomotor muscles from two stages: larval muscle from tail versus adult muscle from hindlimb. Our results revealed that adult muscle fibers exhibited reduced diameter and shorter sarcomere length compared to those of tadpoles. Transcriptomic analysis identified 4103 differentially expressed genes (DEGs), including 2182 up-regulated and 1921 down-regulated genes. Up-regulated genes were mainly involved in energy metabolism and cellular homeostasis pathways, including PPAR signaling and oxidative phosphorylation, whereas down-regulated genes were associated with carbohydrate metabolism and cell proliferation pathways, such as glycolysis/gluconeogenesis and PI3K-Akt signaling. Metabolic profiling indicated a metabolic shift from anaerobic to aerobic energy production, with 57 differential metabolites identified, mainly involved in protein metabolism and insulin-related pathways. Integrated multi-omics analysis further highlighted the AMPK and FoxO signaling pathways play key roles in this process. In conclusion, our findings demonstrate that the metabolic and structural differences between larval and adult skeletal muscles are mediated by AMPK- and FoxO-dependent signaling pathways, providing novel insights into the molecular mechanisms underlying adaptive development and locomotor transition in anuran amphibians.

Animals↗

PubMed2026

Muscle mechanical and architectural adaptations in response to different endurance training modalities in older adults.

INTRODUCTION: This study examined the effects of various cycling endurance training modalities, matched for total workload, on muscle mechanical and architectural characteristics in older adults. METHODS: Fifty healthy participants (25 females, 59-79 yrs) were randomly assigned to five age and sex matched groups: one control and four workload-matched training groups (moderate-intensity continuous, heavy-intensity continuous, high-intensity interval, and heavy-intensity continuous in eccentric cycling). Training consisted of three weekly sessions over 8 weeks, with evaluations conducted at the beginning and end of the intervention with maximal voluntary isometric contractions at five different knee angles (90, 75, 60, 45, 30°) and maximal concentric and eccentric isokinetic contractions at five different knee angular velocities (45, 90, 150, 210, 250°/s). Maximum voluntary isometric torque (Tmax) and optimal knee angle (KAopt) were obtained from the isometric contractions; eccentric torque (Tecc) and maximum concentric knee angular velocity (Vmax) were obtained from the isokinetic contractions. The muscle architecture of vastus lateralis (VL) at rest (muscle thickness, pennation angle, and fascicle length) was investigated as well. RESULTS: No statistical differences were detected between groups or time points in VL architecture, in KAopt and in Vmax. A main effect of time was observed for Tmax (p < 0.001, η2p = 0.458) and Tecc (p = 0.002, η2p = 0.191) in all the investigated training groups. The within-group comparisons indicate significant increases in Tmax in the training groups, but not in the control group. CONCLUSIONS: Commonly applied endurance exercises improve muscle mechanical capacity (Tmax and Tecc) in older adults, with no structural (architectural) muscle remodelling, when matched for workload.

Humans↗

PubMed2026

Intestinal content accelerates muscle protein degradation in red shrimp (Solenocera crassicornis) during refrigeration: Insights from metagenomics and metabolomics.

This study systematically explored the effects of intestinal components on muscle quality deterioration and protein degradation of red shrimp during refrigerated storage. The results demonstrated that refrigeration induced continuous quality degradation and muscle protein breakdown in red shrimp, whereas eliminating intestinal tissues effectively retarded muscle spoilage and protein degradation, and optimized muscle texture. The intestinal microorganisms could secrete extracellular proteases to promote muscle protein degradation were primarily Vibrio, Bacillus, Pseudomonas, Photobacterium, and Shewanella. These microorganisms promote protein degradation by secreting zinc proteases, serine proteases, and aspartyl proteases. This study elucidates the molecular mechanisms of intestinal microbial metabolism influences the muscle protein degradation of red shrimp during refrigeration. The findings provide a theoretical foundation for precise regulation of intestinal-targeted microorganisms, thereby maintaining optimal quality of shrimps during refrigeration.

Animals↗

PubMed2026

Effects of rumen fluid transplantation on longissimus dorsi muscle development in Xizang sheep: An association analysis based on transcriptomic and serum metabolomic profiles.

This study aimed to investigate the effects of rumen fluid transplantation (RFT) on the growth and development of the longissimus dorsi muscle in female Xizang sheep. After RFT, muscle lightness differed significantly between the two groups, with the LDC group showing significantly higher lightness than the LDT group. In contrast, no significant differences were observed between groups in other muscle phenotypic traits, including drip loss, pH, cooking loss, shear force, redness, and yellowness. Antioxidant-related indices (SOD, GSH-PX, MDA, CAT, and T-AOC) also showed no significant differences between groups. Histological analysis revealed that muscle fiber length, width, and density were significantly greater in the experimental group than in the control group. Transcriptomic analysis identified 515 differentially expressed genes (DEGs), of which 419 were downregulated. KEGG analysis indicated that genes involved in muscle development-related pathways, such as cell adhesion and the PI3K-Akt signaling pathway, were predominantly downregulated. Key serum metabolites (L-kynurenine, IPA, allantoin, and propionylcarnitine) showed highly significant positive correlations with muscle fiber growth indices. In contrast, metabolites such as l-carnitine, acetylcarnitine, and citrulline were negatively correlated with muscle fiber growth, but positively correlated with the expression of muscle structure-related genes (COL11A1 and EFNA5) and with meat lightness. Overall, this study provides new insights into the potential molecular basis by which RFT influences muscle growth and development. However, the mechanisms by which RFT affects muscle development and meat quality-related traits remain unclear and warrant further investigation.

Animals↗

PubMed2026

Comparative transcriptome analysis reveals ncRNA-mediated regulatory networks associated with muscle crispiness in grass carp.

Non-coding RNAs (ncRNAs) have been demonstrated to be involved in muscle development and to function as key regulators. However, the molecular mechanism underlying muscle crispiness in grass carp (GC) remains poorly understood, and whether these ncRNAs are involved in its regulation is still unknown. In the current investigation, differentially expressed (DE) RNAs (including lncRNAs, circRNAs, miRNAs, and mRNAs) were identified; concomitantly, target genes prediction was conducted, and functional and signaling pathway enrichment analyses were performed. Pathways related to muscle crispiness were identified, and the competitive endogenous RNA (ceRNA) (lncRNA/circRNA-miRNA-mRNA) regulatory network was further constructed. The results showed that a total of 126 DE-lncRNAs, 17 DE-circRNAs, 329 DE-miRNAs, and 442 DE-mRNAs were identified in muscle tissues of both the GC and crisp grass carp (CGC). GO and KEGG enrichment analyses revealed that target genes of DE-ncRNAs were significantly enriched in signaling pathways, including structural constituents of muscle, apoptosis, oxidative phosphorylation, and regulation of actin cytoskeleton, suggesting that these pathways may be involved in muscle texture remodeling. Subsequently, DE-RNAs enriched in related pathways were identified, and a core ceRNA regulation network comprising 3 lncRNAs, 4 circRNAs, 3 miRNAs, and 17 mRNAs was constructed. Additionally, 10 DE-RNAs from randomly selected groups were validated by qRT-PCR. Our findings not only provide scientific evidence elucidating the molecular mechanisms underlying muscle crispiness in GC but also establish a foundation for studying changes in muscle textural qualities across other fish species.

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PubMed2026

Comprehensive multi-post-translational modifications profiling reveals age-associated remodeling in skeletal muscle.

Sarcopenia, characterized by the progressive loss of skeletal muscle mass and function, is a major hallmark of aging. Post-translational modifications (PTMs) play essential roles in regulating protein activity and cellular homeostasis; however, how multiple PTMs are remodeled during skeletal muscle aging remains incompletely characterized. Here, we performed comprehensive multi-layered proteomic profiling of skeletal muscle from young (3-month-old) and aged (24-month-old) mice, systematically quantifying the global proteome together with five major PTMs: acetylation, phosphorylation, N-glycosylation, O-glycosylation, and ubiquitination. In total, we identified 5 337 proteins and mapped thousands of PTM sites, generating an integrated atlas of age-associated proteomic and PTM remodeling in skeletal muscle. Pathway enrichment analyses revealed distinct modification-specific patterns: acetylation and phosphorylation were predominantly associated with metabolic and mitochondrial-related pathways; N-glycosylation was enriched in immune- and secretory pathway-related processes; O-glycosylation was associated with muscle contraction-related pathways; and ubiquitination was preferentially linked to cytoskeletal organization in muscle cells. Correlation analyses further uncovered diverse association patterns among different PTMs across protein- and modification-level datasets. Phosphorylation and ubiquitination exhibited consistent positive associations, whereas acetylation and ubiquitination showed both inverse and concordant co-variation patterns across subsets of proteins. Phosphorylation and O-glycosylation displayed heterogeneous association patterns across different proteins, and acetylation and phosphorylation demonstrated positive correlations with distinct age-associated directional changes across protein subsets. Together, these results provide a comprehensive, multi-dimensional view of age-associated remodeling of the skeletal muscle proteome and multiple PTM layers, offering a valuable resource for understanding molecular alterations accompanying muscle aging and sarcopenia.

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PubMed2026

Transcriptomic insights into temperature regulation of proliferation and differentiation in skeletal muscle cells of Nibea albiflora.

Myogenesis involves sequential stages of muscle satellite cell activation, myoblast proliferation, differentiation, and fusion into multinucleated myotubes. Teleost muscle exhibits indeterminate growth and is highly sensitive to environmental temperature, yet the underlying mechanisms by which temperature regulate proliferation and differentiation remain poorly understood. In this study, we established a primary skeletal muscle cell culture from the yellow drum (Nibea albiflora), an economically important marine fish, and integrated morphological observations with comparative transcriptomics analysis to characterize cellular and molecular responses at 28 °C and 20 °C during both proliferation and differentiation stages. Phenotypic analysis revealed that 28 °C significantly enhanced both myoblast proliferation and myogenic differentiation ability compared with 20 °C. Transcriptomic profiling revealed that at 28 °C, differentiation upregulated extracellular matrix(ECM) organization, calcium signaling, and sarcomere assembly, while proliferation enhanced focal adhesion, growth factor signaling, and lipid metabolism. At 20 °C, differentiation was characterized by glutathione metabolism, and ferroptosis, while proliferation involved cytokine-cytokine receptor interaction and negative regulation of signal transduction. Core myogenic regulatory factors (MRFs), particularly myogenin, were strongly upregulated at 28 °C during the differentiation stage, serving as an internal control. Based on these findings, we propose a testable model that elevated temperature coordinates Ca2+-dependent MRF activation with ECM-integrin signaling to drive sarcomere assembly and muscle growth. Key differentially expressed genes (DEGs) regulating myogenesis in N. albiflora were also identified. This study provides a mechanistic framework for temperature adaptation in teleost skeletal muscle and identifies candidate genes for functional validation and marker-assisted selection, as well as a rationale for temperature management strategies to improve aquaculture yield of N. albiflora.

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PubMed2026

Comparative analysis of histological and transcriptomic characteristics in caudal muscles of nile crocodiles (Crocodylus niloticus), siamese crocodiles (Crocodylus siamensis), and their hybrids.

Crocodylus niloticus and Crocodylus siamensis are high-value aquaculture species. C. niloticus is large-bodied but less abundant, while C. siamensis grows fast but is small-sized. Their hybrids combine parental advantages, yet relevant research is scarce. This study compared the histological and transcriptomic characteristics of the caudal muscle across the three taxa. HE staining indicated that C. niloticus had significantly larger myofiber diameters (p < 0.05); C. siamensis had the smallest, and the myofiber density of hybrids was much closer to that of C. siamensis. Masson's trichrome staining indicated that C. niloticus had the thickest collagen fibers (p < 0.05), C. siamensis the thinnest, and hybrids exhibited highly similar histological traits to C. siamensis. C. niloticus had higher LDH and SDH activities in caudal muscles, whereas the hybrid crocodile indicated the highest CK activity. Transcriptomic analysis identified numerous differentially expressed genes (DEGs), which were enriched in growth, muscle metabolism, and energy allocation pathways via GO/KEGG annotations. PPI analysis screened 24 hub genes related to energy metabolism. This study systematically reveals caudal muscle differences, providing insights into growth-related molecular mechanisms and theoretical support for crocodile artificial breeding.

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PubMed2026

Effects of passive blood flow restriction on muscle function following exercise-induced muscle damage in recreationally active males.

This investigation examined the effects of passive blood flow restriction (pBFR) on indices of exercise-induced muscle damage (EIMD) in recreationally active males. Fifteen males completed six consecutive visits (±2 hours). Participants completed 3 × 25 maximal, unilateral, isokinetic (60°·s-1), concentric-eccentric leg extensions on both legs. Each leg was randomly assigned to receive pBFR (80% arterial occlusion pressure) or sham (20 mmHg) at 0, 24, 48, 72, and 96 hours post-EIMD. Perceived muscle soreness, range of motion (ROM), pain pressure threshold (PPT), concentric peak torque (CPT), and maximal voluntary isometric contraction (MVIC) torque were assessed and analyzed using separate linear mixed-effects models. Perceived muscle soreness increased at 24 hours (mean difference [meandiff] = 4.9 au; p < 0.001) and recovered by 96 hours (p = 0.482), with no differences between conditions (p = 0.450). ROM (meandiff = -3.1°; p = 0.040), PPT (meandiff = -1.63 kgf; p < 0.001), CPT (meandiff = -27.7 Nm; p < 0.001), and MVIC torque (meandiff = -30.8 Nm; p < 0.001) decreased at 24 hours, with recovery occurring between 48-96 hours. Condition-specific differences were observed for ROM (meandiff = 2.5°; p < 0.001), PPT (meandiff = 0.49 kgf; p = 0.005), CPT (meandiff = 6.2 Nm; p = 0.020), and MVIC torque (meandiff = 7.1 Nm; p = 0.044), which were greater in pBFR than sham. These findings suggested that pBFR may reduce impairments in ROM, PPT, CPT, and MVIC torque following EIMD, despite a similar recovery trajectory between conditions.

Humans↗

PubMed2026

The effects of nitrate and nitrite supplementation on mitochondrial respiration in permeabilized muscle fibres in young healthy adults.

Nitric oxide (NO) is a direct regulator of mitochondrial respiration. Nitrate (NO3-) and nitrite (NO2-) are good sources of NO, but whether their effects on mitochondrial respiration differ between in vivo and in vitro administration remains unclear. In Study 1, 8 participants consumed NO3- -rich beetroot juice (BR) (∼12.8 mmol NO3-) and NO3- -depleted placebo beetroot juice (PL) (∼0.08 mmol NO3-) acutely and chronically for 2 weeks in a randomised, double-blind, crossover design. A substrate-uncoupler-inhibitor titration (SUIT) protocol was used to assess mitochondrial respiration using high-resolution respirometry (oxygen tension: ∼200-450 μM) in permeabilized muscle fibres. In Study 2, skeletal muscle samples were collected from 11 participants. In a randomised, crossover design, different doses (0, 1.5, and 3.0 μM) of sodium nitrite (NaNO2) were administered to permeabilized muscle fibres. Mitochondrial respiration was measured using the same SUIT protocol under lower oxygen tension (∼50-200 μM). Although muscle NO3- concentration significantly increased after both acute and chronic BR supplementation, mitochondrial respiration and exercise performance did not differ between PL and BR in either condition. Similarly, absolute oxygen flux across different respiratory states were not different between different doses of NaNO2. However, the leak control ratio, reflecting the degree of uncoupling of mitochondrial respiration, was significantly higher with 3.0 μM NaNO2 administration (0.12 ± 0.05) compared to 0 μM NaNO2 administration (0.09 ± 0.04, P = 0.03). These findings, involving both in vivo and in vitro administration approaches, albeit in the presence of relatively high oxygen concentrations, suggest that neither NO3- nor NO2- improves mitochondrial respiration, at least in young healthy adults.

Humans↗

PubMed2026

Integrated miRNA-mRNA profiling reveals candidate regulatory relationships associated with high-fat diet-induced muscle lipid deposition in black seabream (Acanthopagrus schlegelii).

High-fat diets are increasingly used in aquaculture due to their protein-sparing effects; however, the post-transcriptional regulatory mechanisms of fish muscle in response to high-fat diets (HFD) remain unclear. In this study, juvenile black seabream were fed either a normal-fat diet (NFD) or a HFD to investigate the miRNA-mRNA regulatory network associated with diet-induced muscle lipid deposition. Oil Red O staining and biochemical analysis showed that high-fat diet feeding markedly increased lipid droplet accumulation and crude lipid content in muscle, indicating significant induction of muscle lipid deposition. Integrated mRNA and miRNA expression profiling revealed substantial transcriptomic and post-transcriptional responses to high-fat diet challenge. A total of 271 differentially expressed genes were identified, including 120 upregulated and 151 downregulated genes. Through combined target prediction and expression correlation analysis, thirteen candidate inverse miRNA-mRNA relationships were subsequently identified, and RT-qPCR supported the expression patterns of selected miRNAs and mRNAs. These pairs included miR-499-x-dmgdh, miR-499-y-gatm, miR-727-y-ass1, miR-4649-x-foxo4, miR-9129-z-myl7, and several novel miRNA-mediated interactions involving adk, chst11, lypla2, frem2, kcnc4, wars1, bag2, and capn2. Functional analysis suggested that these regulatory pairs were mainly associated with metabolic adaptation, structural remodeling, and cellular stress responses. In particular, gatm, dmgdh, ass1, and adk were associated with energy metabolism-related processes, including pathways previously linked to Ampk regulation, whereas myl7, frem2, and kcnc4 may contribute to muscle structural maintenance and excitability regulation. Overall, this study provides candidate miRNA-mRNA regulatory relationships potentially involved in high-fat diet-induced muscle lipid deposition and adaptive remodeling in black seabream, offering a basis for future functional studies on muscle metabolism and quality regulation in marine fish.

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PubMed2026

Mitochondrial dysfunction in muscle cells induced by snoring vibrations.

Snoring-related vibrations have been proposed as a pathogenic factor contributing to upper airway muscle dysfunction in patients with obstructive sleep apnea (OSA). To investigate whether exposure to snoring vibration is linked to muscle weakness, we used an in vitro vibration model to examine its effects on mitochondrial homeostasis in L6 muscle cells at 8, 12, 24, and 48 h. The findings were then compared with mitochondrial alterations in the upper airway muscles from snorers and patients with OSA. Proteomic analysis of L6 myoblasts revealed extensive remodeling of the mitochondrial proteome at 8 h, affecting pathways involved in oxidative phosphorylation, protein import, ribosome biogenesis, and RNA processing. Respiratory chain remodeling was subunit-specific, with increased abundance of selected components of Complexes I, IV, and V, including NDUFS4, COX5A, and ATP5PD. However, reductions in spliceosome-associated factors, such as SRSF2 and DDX46, along with alterations in mitochondrial ribosomal proteins, indicated impaired RNA processing and protein synthesis. Furthermore, both proteomic and transcriptomic analyses revealed activation of a mechanosensing-mechanotransduction axis, with early upregulation of integrin subunits and mechanosensitive ion channels, followed by transient activation of focal adhesion signaling. Despite transcriptional upregulation of selected Complex IV subunits Cox5a and Cox6a2, this response was accompanied by accumulation of unspliced pre-mRNA, indicating impaired RNA processing efficiency and a decoupling between transcript and protein levels. Real-time Seahorse assay revealed a collapse of mitochondrial respiration and glycolytic reserve at 8 h. Although mitochondrial oxygen consumption recovered after 48 h, the ability to dynamically upregulate glycolysis remained impaired. In patients, muscle capillarization was impaired, COX activity was reduced, and mitochondrial organization was disrupted. Moreover, transcription of Complex IV subunits COX5A and COX6A2 was, as in vibrated L6 cells, upregulated, suggesting a mismatch between transcript levels and protein expression. We conclude that snoring-induced vibrations are an unrecognized stressor that disrupts mitochondrial homeostasis in muscle by impairing RNA processing, protein synthesis, and mechanotransduction-driven mitochondrial remodeling, leading to transcript-protein uncoupling and likely muscle dysfunction.

Humans↗

PubMed2026

Low Carbohydrate Availability in Energy Balance Alters Bone Turnover and Muscle Proteomic Response With Limited Endocrine Disruption.

Training with low carbohydrate availability (LCA) has been proposed as an independent determinant of physiological perturbations commonly attributed to low energy availability (LEA) and to increase skeletal muscle oxidative machinery, yet the effects of LCA in isolation from LEA remain unclear. We examined whether short-term carbohydrate restriction under energy balance alters endocrine and metabolic markers associated with LEA and skeletal muscle proteomic response. In a randomized crossover design, eight trained males completed 4 days of either a low-carbohydrate high-fat diet (LOW; 12% carbohydrate, 69% fat, 19% protein) or a normal-carbohydrate diet (NORM; 62% carbohydrate, 19% fat, 19% protein), while undertaking daily cycloergometer exercise (15 kcal kg FFM-1 day-1) and maintaining energy availability at 45 kcal kg FFM-1 day-1. LOW induced a clear metabolic shift consistent with LCA, evidenced by elevated circulating free fatty acids, glycerol and β-hydroxybutyrate, in fasting conditions and fat oxidation at rest and during exercise, alongside reduced exercise glucose concentrations. Despite these responses, LOW did not alter insulin, testosterone, triiodothyronine, leptin, hepcidin, or P1NP. In contrast, β-CTX increased and IGF-1 decreased relative to NORM. Muscle glycogen concentration decreased only in LOW (40% ± 14%). Proteomic analysis identified 671 proteins; 57 differentially expressed in LOW relative to NORM were limited to fatty acid metabolism pathways and suppression of ribosomal, sarcomeric, and extracellular matrix proteins. These findings indicate that isolated LCA exerts limited endocrine disruption but may selectively compromise bone turnover and muscle anabolic response, suggesting that without acute LEA, LCA has limited influence on muscle oxidative phenotype.

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PubMed2026

Effects of Progressive Inspiratory Muscle Training on Lung Volume and Respiratory Strength in Patients With Pre-Dialysis Chronic Kidney Disease.

INTRODUCTION: Chronic kidney disease can present changes in thoracic cavity volume and respiratory muscle weakness, even in the pre-dialysis stage. However, there is little evidence on the effects of inspiratory muscle training in these patients. METHODS: This was a randomized clinical trial which comprised patients with Chronic Kidney Disease in stages 3, 4, and 5 undergoing conservative treatment, allocated experimental group (EG) with progressive loading (up to 50% of maximal inspiratory pressure [MIP]) and control group (CG) with a fixed load (5 cmH2O) and no load progression performed daily for 8 weeks. The outcomes assessed were thoracic cavity volumes, as measured by optoelectronic plethysmography, and inspiratory and expiratory respiratory muscle strength. RESULTS: A total of 30 patients completed the study. All volumes significantly increased at the end of the protocol with a large effect size, but only the pulmonary thoracic cavity volume showed a significant interaction (F = 3.698; p = 0.042). There was an increase in inspiratory muscle strength in the EG (73.88-90.35 cmH2O; p < 0.001) and in the CG (70.85-86.92 cmH2O; p = 0.001), as well as in expiratory muscle strength in the EG (97.71-108.53 cmH2O; p = 0.001) and in the CG (80.69-94.77 cmH2O; p = 0.004). CONCLUSION: Daily IMT increased thoracoabdominal volumes, particularly pulmonary rib cage volume in the progressive-load group, as well as respiratory muscle strength in patients with pre-dialysis CKD. However, progressive-load IMT was not superior to minimal-load training.

Humans↗

PubMed2026

Risk factors for loss of skeletal muscle mass in patients with chronic kidney disease on a low-protein diet.

OBJECTIVES: A low-protein diet (LPD) is recommended for patients with chronic kidney disease (CKD) to prevent a further decline in renal function. However, its impact on muscle mass in these patients remains unclear. This study investigated the risk factors for loss of muscle mass in patients with CKD on an LPD. METHODS: Eighty-four patients with predialysis CKD (59 men, mean age 61.9 ± 11.5 y) who participated in a multicenter randomized controlled trial initiated in 2014 were retrospectively reviewed. We collected data on baseline blood and urine tests, body composition, and dietary records at the start and end of the observation period. We evaluated muscle mass using the skeletal muscle index (SMI) and analyzed risk factors for a decrease in SMI during the 24-wk observation period, using logistic regression analysis. Variables with an association (P < 0.1) in univariate analysis, as well as age, sex, use of low-protein rice, and changes in protein intake, were subjected to multivariate analysis. RESULTS: SMI decreased in 50 patients (59.5%) during the observation period. Multivariate analysis identified significant associations of the SMI with serum albumin at baseline (odds ratio 0.11, 95% confidence interval 0.02-0.52, P = 0.004) and changes in energy intake while on the LPD (odds ratio 3.39, 95% confidence interval 1.00-11.43, P = 0.049). CONCLUSIONS: Risk factors for reduced SMI in patients with CKD on an LPD were malnutrition when initiating the LPD and reduced energy intake during its implementation. Clinicians should optimize nutritional status before initiation of an LPD and ensure adequate energy intake throughout treatment.

Humans↗

PubMed2026

Effects of essential amino acid supplementation on musculotendinous recovery following eccentric plantar flexor exercise: a randomized controlled trial.

BACKGROUND: Exercise-induced muscle damage (EIMD) resulting from eccentric contractions leads to transient impairments in muscle function. Essential amino acids (EAAs) stimulate muscle protein synthesis and may support recovery following damaging exercise. However, limited research has examined the effects of EAAs on muscle function following eccentric plantar flexor exercise. The purpose of this study was to examine the effects of EAA supplementation on indirect markers of muscle and musculotendinous recovery following EIMD. METHODS: Thirty-six recreationally active males (age: 21.2 ± 2.7 years) were randomly assigned to an EAA group (10 g of EAAs), placebo (10 g of maltodextrin), or control (no supplementation). Supplements were consumed 30 minutes before and immediately after an eccentric plantar flexor protocol (4 × 50 repetitions followed by one set to failure) and during the 72 hours recovery period. Indirect markers of muscle damage were assessed pre-exercise, immediately post-exercise, and 24, 48, and 72 hours post-exercise, consisting of perceived soreness (NPRS), pain pressure threshold (PPT), calf muscle thickness and Achilles tendon thickness (ultrasound), and calf circumference. RESULTS: The eccentric protocol elicited responses consistent with EIMD, including increased soreness (p < 0.001), increased calf muscle thickness and circumference (p < 0.001), and reduced PPT (p = 0.018). EAA supplementation attenuated soreness at 24 hours compared with placebo. Calf muscle thickness increased following exercise in both groups; however, swelling returned to baseline by 72 hours in the EAA group but remained elevated in placebo (Condition × Time, p < 0.001). Achilles tendon thickness decreased immediately post-exercise (p = 0.005) but was not influenced by supplementation. CONCLUSIONS: EAA supplementation modestly reduced soreness and was associated with faster recovery of muscle swelling but did not influence tendon morphology within 72 hours.

Humans↗

PubMed2026

Effect of Motor-Control Exercises on Scapulohumeral and Scapulothoracic Muscle Activations in Athletes With Secondary Subacromial Impingement Syndrome.

CONTEXT: Unbalanced or uncoordinated activity across either the scapulohumeral or the scapulothoracic muscle may impair scapulohumeral rhythm during arm elevation. OBJECTIVE: To compare the effects of progressive resistance exercises (PREs), integrated with and without facilitatory motor-control exercises (MCEs), on scapulohumeral and scapulothoracic myoelectric activities in overhead athletes diagnosed with secondary subacromial impingement syndrome (SAIS). DESIGN: Randomized controlled clinical trial. SETTING: Neuromuscular Rehabilitation Research Center. PATIENTS OR OTHER PARTICIPANTS: Overhead athletes diagnosed with secondary SAIS were assigned randomly to 3 parallel groups: 2 intervention groups and 1 control group. INTERVENTIONS: All groups received contemporary physical therapy modalities every other day for 8 weeks. Intervention groups I and II also completed scapulohumeral and scapulothoracic PREs, integrated, respectively, with and without facilitatory MCEs targeting infraspinatus and lower trapezius muscles. MAIN OUTCOME MEASURES: Scapulohumeral and scapulothoracic myoelectric activities were recorded during scapular arm abduction between 80° and 110° before and after the prescribed treatment protocols. RESULTS: Scapulohumeral and scapulothoracic PREs reduced the corresponding myoelectric activities during scapular arm abduction within the groups (P ≤ .02, partial η2 ≥ 0.127). Facilitatory biofeedback-guided exercises integrated into PREs preserved scapulohumeral and scapulothoracic myoelectric activities (P ≤ .03), excluding teres minor myoelectric activity (P > .99). CONCLUSIONS: Scapulohumeral and scapulothoracic PREs reduced the corresponding muscle activations during scapular arm abduction in overhead athletes with secondary SAIS. Facilitatory MCEs targeting infraspinatus and lower trapezius muscles, integrated into PREs, preserved scapulohumeral and scapulothoracic muscle activations.

Humans↗