Search Results (1,216)

Laboratory-based assessment of cardiorespiratory function is a widely applied method in sports science. Most performance evaluations focus on oxygen uptake parameters. Despite the well-established concept of oxygen deficit introduced by Hill in the 1920s, relatively few studies have examined its behavior during submaximal exercise, with limited exploration of deficit dynamics. The present study aimed to analyze the behavior of oxygen deficit in young female handball players (N = 42, age: 15.4 ± 1.3 years) during graded exercise. Oxygen deficit was estimated using the American College of Sports Medicine (ACSM) algorithm, restricted to subanaerobic threshold segments of a quasi-ramp exercise protocol. Cardiorespiratory parameters were measured with the spiroergometry test on treadmills, and body composition was assessed via Dual Energy X-ray Absorptiometry (DEXA). Cluster and principal component analyzes revealed two distinct athlete profiles with statistically significant differences in both morphological and physiological traits. Cluster 2 showed significantly higher relative VO₂ peak (51.43 ± 3.70 vs. 45.70 ± 2.87 mL·kg⁻¹·min⁻¹; p < 0.001; Cohen’s d = 1.76), yet also exhibited a greater oxygen deficit per kilogram (39.03 ± 16.71 vs. 32.56 ± 14.33 mL·kg⁻¹; p = 0.018; d = 0.80). Cluster 1 had higher absolute body mass (69.67 ± 8.13 vs. 59.66 ± 6.81 kg; p < 0.001), skeletal muscle mass (p < 0.001), and fat mass (p < 0.001), indicating that body composition strongly influenced oxygen deficit values. The observed differences in oxygen deficit profiles suggest a strong influence of genetic predispositions, particularly in cardiovascular and muscular oxygen utilization capacity. Age also emerged as a critical factor in determining the potential for adaptation. Oxygen deficit during submaximal exercise appears to be a multifactorial phenomenon shaped by structural and physiological traits. While certain influencing factors can be modified through training, others especially those of genetic origin pose inherent limitations. Early development of cardiorespiratory capacity may offer the most effective strategy for long-term optimization. Full article

Globins are a class of globular proteins that function in the transportation or storage of oxygen. They are critical for cellular metabolism. Notable examples include hemoglobin, which is found in red blood cells, and myoglobin, which is present in muscle cells. Approximately two decades ago, a third globin, designated as neuroglobin, was identified, expressed predominantly in neuronal cells. This was followed two years later by the fourth, cytoglobin, found in cells of the fibroblast lineage, as well as in neuronal cell populations of the central and nervous systems. Both neuroglobin and cytoglobin have been found in the sensory and endocrine systems, albeit inconsistently, and it is thought that they are engaged in functions such as oxygen transport and storage, scavenging of free radicals, NO metabolism, peroxidase activity, and signaling functions. Neuroglobin is also expressed in astrocytes under challenging conditions. Common neuroscience methods were utilized to study the distribution and regulation of globin tissues and of single brain cells. Despite considerable overlap in the findings of various studies, some results deviate significantly from other studies. The potential causes of these discrepancies may include variations in detection methods, animal age and sex, time of day and year, and differing cell culture conditions. This review will explore factors that may influence functional aspects of globins and their detection in the mammalian brain. Full article

Hypoxia represents a critical environmental stressor in aquaculture, significantly disrupting aquatic organisms’ physiological homeostasis and thereby constraining the sustainable development of aquaculture industries. To elucidate the mechanisms underlying hypoxia-induced metabolic regulation in aquatic species, this study employed hybrid yellow catfish (Pelteobagrus vachelli ♀ × Leiocassis longirostris ♂) as a model organism to systematically investigate the multidimensional physiological responses in brain, liver, and muscle tissues under hypoxia (0.7 mg/L) and reoxygenation (7.0 mg/L) conditions. Through qRT-PCR and enzymatic activity analyses, we comprehensively assessed molecular alterations associated with oxygen sensing (HIF-1α gene), respiratory metabolism (PFKL, HK1, PK, CS, and LDHA genes and corresponding enzyme activities), oxidative stress (SOD1, SOD2, GSH-PX, and CAT genes, along with LPO, MDA, PCO, T-SOD, GSH-PX, and CAT levels), apoptosis (Caspase-3, Bax/Bcl-2), inflammatory response (IL-1β, IKKβ), and mitochondrial function (COXIV, PGC-1α, ATP5A1). Key findings demonstrated pronounced HIF-1α activation across all examined tissues. Hepatic tissues exhibited adaptive metabolic reprogramming from aerobic to anaerobic metabolism, whereas cerebral tissues displayed suppressed anaerobic glycolysis during prolonged hypoxia, and muscular tissues manifested concurrent inhibition of both glycolytic and aerobic metabolic pathways. Notably, skeletal muscle exhibited marked oxidative stress accompanied by mitochondrial dysfunction, exacerbated inflammation, and apoptosis activation during hypoxia/reoxygenation cycles. This study delineates tissue-specific adaptive mechanisms to hypoxia in yellow catfish, providing theoretical foundations for both piscine hypoxia physiology research and aquaculture practices. Full article

Background: Repeated high-intensity intervals under normoxic (NOR) and hypoxic (HYP) conditions is a training strategy used by athletes. Although different protocols have been used, the effect of longer recovery between repetitions is unclear. In addition, information on the effect of repeated high-intensity intervals on HYP in women is scarce. Aims: To analyse the differences between sexes and between conditions (NOR and HYP) in Repeated Wingate (RW) performance and neuromuscular fatigue in triathletes. Methods: A total of 12 triathletes (men: n = 7, 23.00 ± 4.04 years; women: n = 5, 20.40 ± 3.91) participated in this randomised, blinded, crossover study. In two separate sessions over seven days, participants performed 3 × 30” all out with 7′ of recovery in randomised NOR (fraction of inspired oxygen: ≈20%; ≈300 m altitude) and HYP (fraction of inspired oxygen: ≈15.5%; ≈2500 m altitude) conditions. Before and after RW, vertical jump tests were performed to assess neuromuscular fatigue. Oxygen saturation, power, perceived exertion, muscle soreness and heart rate parameters were assessed. Results: Significant differences were reported between sexes in the parameters of vertical jump, oxygen saturation, RW performance and heart rate (p < 0.05). However, between conditions (NOR and HYP), only differences in oxygen saturation were reported (p < 0.05). No significant differences were reported between conditions (NOR and HYP) in RW performance, neuromuscular fatigue, muscle soreness and perception of exertion. Conclusions: A 3 × 30” RW protocol with 7′ recovery in HYP could have no negative consequences on performance, neuromuscular fatigue and perception of exertion in triathletes compared to NOR, independently of sex. Full article

Skeletal muscle atrophy is a debilitating condition characterized by the loss of muscle mass and function. It is commonly associated with aging, chronic diseases, disuse, and prolonged glucocorticoid therapy. Oxidative stress and catabolic signaling pathways play significant roles in the progression of muscle degradation. Despite its clinical relevance, few effective therapeutic options are currently available. In this study, we investigated the protective effects of an ethanolic extract of Glycine Semen Preparata (GSP), i.e., fermented black soybeans, using in vitro and in vivo models of dexamethasone (Dexa)-induced muscle atrophy. In C2C12 myoblasts and myotubes, GSP significantly attenuated both oxidative stress-induced and Dexa-induced damages by reducing reactive oxygen species levels and by suppressing the expression of the muscle-specific E3 ubiquitin ligases MuRF1 and Atrogin-1. Moreover, GSP upregulated key genes involved in muscle regeneration (Myod1 and Myog) and mitochondrial biogenesis (PGC1α), indicating its dual role in muscle protection and regeneration. Oral administration of GSP to mice with Dexa-induced muscle atrophy resulted in improved muscle fiber integrity, increased proportion of large cross-sectional area fibers, and partial recovery of motor function. Isoflavone aglycones, such as daidzein and genistein, were identified as active compounds that contribute to the beneficial effects of GSP through antioxidant activity and gene promoter enhancement. Thus, GSP is a promising nutraceutical that prevents or mitigates muscle atrophy by targeting oxidative stress and promoting myogenesis and mitochondrial function. Further studies are warranted to standardize the bioactive components and explore their clinical applications. Full article

Doxorubicin (DOX) is a highly effective chemotherapy drug used in the treatment of many cancers, including solid tumors, hematological malignancies, and soft tissue sarcomas. Despite its potent antitumor effects, DOX is known to have toxic effects in non-tumorous tissues, such as skeletal muscle. Potential mediators of DOX-induced skeletal muscle toxicity are reactive oxygen species (ROS). An overproduction of ROS can disrupt the balance between oxidants and antioxidants in a cell, leading to oxidative stress. Chronic oxidative stress has been shown to upregulate proteolysis, ultimately leading to muscle wasting. Exercise stands as a potent nonpharmacological therapy capable of attenuating muscle wasting by enhancing metabolic function and antioxidant defenses while suppressing harmful ROS production. This review focuses on the current understanding of the role of oxidative stress in DOX-induced skeletal muscle toxicity. In addition, we highlight the effects of various exercise types on oxidative stress and muscle remodeling during DOX chemotherapy. Full article

In placental mammals, the co-option of vertebrate orthologous ATP1B4 genes has profoundly altered the properties of the encoded BetaM proteins, which function as bona fide β-subunits of Na,K-ATPases in lower vertebrates. Eutherian BetaM acquired an extended Glu-rich N-terminal domain resulting in the complete loss of its ancestral function and became a skeletal and cardiac muscle-specific component of the inner nuclear membrane. BetaM is expressed at the highest level during perinatal development and is implicated in gene regulation. Here we report the long-term consequences of Atp1b4 ablation on metabolic parameters in adult mice. Male BetaM-deficient (Atp1b4−/Y) mice have remarkably lower body weight and adiposity than their wild-type littermates, despite higher food intake. Indirect calorimetry shows higher energy expenditure (heat production and oxygen consumption) with a greater spontaneous locomotor activity in Atp1b4−/Y males. Their lower respiratory exchange ratio suggests a greater reliance on fat metabolism compared to their wild-type counterparts. Consistently, Atp1b4−/Y KO mice exhibit enhanced β-oxidation in skeletal muscle, along with improved glucose and insulin tolerance. These robust metabolic changes induced by Atp1b4 disruption demonstrate that eutherian BetaM plays an important role in regulating adult mouse metabolism. This demonstrates that bypassing the co-option of Atp1b4 potentially reduces susceptibility to obesity. Thus, Atp1b4 ablation leading to the loss of evolutionarily acquired BetaM functions serves as a model for a potential alternative pathway in mammalian evolution. Full article

Strength training has established itself as an essential component in physical conditioning programmes, not only to improve sports performance, but also for health purposes. To evaluate the effects of a strength training protocol with a predominance of the eccentric component on blood count, blood chemistry, and quadriceps muscle ultrasound in university students. 31 students (22.3 ± 4.14 years) of the professional programme in Sports of the Politécnico Colombiano Jaime Isaza Cadavid participated. A mesocycle was developed with three weekly sessions of eccentric training focused on the lower body and core zone. Pre and post-intervention measurements were taken anthropometry, haemogram, lipid profile, ultrasound of the right quadriceps, Bosco test, and Rockport test. The Wilcoxon signed-rank test was used, and the effect size was calculated using rank correlation. Statistically significant changes were observed in haematocrit, mean corpuscular volume, HDL, muscle thickness and echo-intensity, vertical jump power, and maximal oxygen consumption. A four-week eccentric strength training programme generates improvements in haematology, lipid profile, muscle quality assessed by ultrasound, and functional performance in university students. Full article

Muscle activity during exercise is typically assessed using oximeters, to evaluate local oxygen saturation (SmO₂), or surface electromyography (sEMG), to analyze electrical activation. Despite the importance of combining these analyses, no study has evaluated both of them during specific swimming exercises in combination with mechanical power output. This study aimed to assess muscle activity during an incremental test on a swim-bench utilizing oximeters and sEMG. Nine male swimmers performed a five-steps test: PRE (3 min at rest), STEP 1, 2, and 3 (swimming at a frequency of 25, 30, and 40 cycle/min for a duration of 2, 2, and 1 min, respectively), and POST (5 min at rest). Each swimmer wore two oximeters and sEMG, one for each triceps brachii. Stroke frequency and arm mechanical power (from ~13 to ~52 watts) estimated by the swim-bench were different among all steps, while no differences between arms were found. SmO₂ (from ~70% to ~60%) and sEMG signals (from ~20 to ~65% in signal amplitude) showed a significant increase among all steps. In both arms, a large/very large correlation was found between mechanical power and SmO₂ (r < −0.634), mechanical power and sEMG onset/amplitude (r > 0.581), and SmO₂ and sEMG amplitude (r > 0.508). No correlations were found between the slope of the sEMG spectral indexes and the slope of SmO₂; only sEMG detected electrical manifestation of muscle fatigue through the steps (p < 0.05). Increased muscle activity, assessed by both oximeters and sEMG, was found at mechanical power increases, revealing both devices can detect effort variation during exercise. However, only sEMG seems to detect peripheral manifestations of fatigue in dynamic conditions. Full article

Elite soccer places significant neuromuscular and metabolic stress on athletes, leading to elevated production of reactive oxygen and nitrogen species (RONS), particularly in skeletal muscle, where intense contractile activity and increased oxygen flux drive oxidative processes. These reactive species play a dual role in skeletal muscle, supporting adaptive signaling at controlled levels while causing oxidative damage when poorly regulated. This paper presents an integrated synthesis of current knowledge on redox biology in elite soccer players, focusing on the origins and regulation of RONS, the functions of enzymatic and non-enzymatic antioxidant systems, and how both RONS and antioxidant responses influence muscle performance, fatigue, recovery, and long-term physiological adaptation. Drawing on studies conducted between 2000 and 2025, the discussion underscores the seasonal fluctuations in oxidative stress, individual variability in redox responses, and the potential adverse effects of unsystematic antioxidant supplementation. The analysis also emphasizes the value of using biomarker-guided, periodized antioxidant interventions tailored to training demands. Future directions include longitudinal tracking and the use of AI-assisted monitoring to enable personalized strategies for maintaining redox balance and optimizing performance in elite sport. Full article

Background: Under oxidative stress conditions, the increased levels of reactive oxygen species (ROS) within cells disrupt the intracellular homeostasis. Tartary buckwheat peptides exert their effects by scavenging oxidative free radicals, such as superoxide anion and hydrogen peroxide, thereby reducing oxidative damage within cells. Meanwhile, these peptides safeguard mitochondria by maintaining the mitochondrial membrane potential, decreasing the production of mitochondrial oxygen free radicals, and regulating mitochondrial biogenesis and autophagy to preserve mitochondrial homeostasis. Through these mechanisms, Tartary buckwheat peptides restore the intracellular redox balance, sustain cellular energy metabolism and biosynthesis, and ensure normal cellular physiological functions, which is of great significance for cell survival and adaptation under oxidative stress conditions. Objectives: In this experiment, a classical cellular oxidative stress model was established. Indicators related to antioxidant capacity and mitochondrial membrane potential changes, as well as pathways associated with oxidative stress, were selected for detection. The aim was to elucidate the effects of Tartary buckwheat oligopeptides on the metabolism of cells in response to oxidative stress. Methods: In this study, we established an oxidative damage model of mouse skeletal muscle myoblast (SOL8) cells using hydrogen peroxide (H₂O₂), investigated the pre-protective effects of Tartary buckwheat oligopeptides on H₂O₂-induced oxidative stress damage in SOL8 cells at the cellular level, and explored the possible mechanisms. The CCK-8 method is a colorimetric assay based on WST-8-[2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodiumsalt], which is used to detect cell proliferation and cytotoxicity. Results: The value of CCK-8 showed that, when the cells were exposed to 0.01 mmol/L H₂O₂ for 1 h and 10 mg/mL Tartary buckwheat oligopeptides intervention for 48 h, these were the optimal conditions. Compared with the H₂O₂ group, the intervention group (KB/H₂O₂ group) showed that the production of ROS was significantly reduced (p < 0.001), the malondialdehyde (MDA) content was significantly decreased (p < 0.05), and the activity of catalase (CAT) was significantly increased (p < 0.01); the mitochondrial membrane potential in the KB/H₂O₂ group tended to return to the level of the control group, and they all showed dose-dependent effects. Compared with the H₂O₂ group, the mRNA expression of KEAP1 in the KB/H₂O₂ group decreased, while the mRNA expression of NRF2α, HO-1, nrf1, PGC-1, P62, and PINK increased. Conclusions: Therefore, Tartary buckwheat oligopeptides have a significant pre-protective effect on H₂O₂-induced SOL8 cells, possibly by enhancing the activity of superoxide dismutase, reducing ROS attack, balancing mitochondrial membrane potential, and maintaining intracellular homeostasis. Full article

This study investigated whether the addition of nitrate (from beetroot) to an isotonic drink provided over 5 days would affect sprint interval exercise (SIE) performance and muscle oxygenation. Twenty (seven female) physically active participants (mean ± SD; age 28 ± 6 years, BMI 22.6 ± 2.0 kg/m²) completed a double-blind, randomized, crossover study where they consumed 570 mL of either isotonic drink (ISO-C) or isotonic beetroot juice drink (ISO-BR) for 5 days before performing SIE (six 10 s maximal effort, interspersed with 50 s active recovery) on a cycle ergometer. Both drinks contained equal osmolality (290 mOsm/kg) but differed in the nutrients from beetroot extract, particularly the nitrate content (ISO-C: 0 mmol, ISO-BR: 12.9 mmol). ISO-BR significantly reduced the average time to peak power (ISO-C: 2.0 ± 0.18 s vs. ISO-BR: 1.6 ± 0.37 s; main effect of drink, p = 0.003, partial η² = 0.04) and increased muscle deoxygenation (ΔHHb) (main effect of drink, p = 0.002, partial η² = 0.021) compared to ISO-C. Five-day supplementation with ISO-BR improved the time to peak power but not the peak or mean power output for SIE compared with ISO-C. Full article

Background: Obstructive sleep apnea syndrome (OSAS) is associated with altered body composition, including increased fat accumulation and potential reductions in muscle quality. Sarcopenic obesity—a condition marked by simultaneous muscle degradation and adiposity—is of growing concern in OSAS populations. Methods: We conducted a retrospective study evaluating thoracoabdominal CT scans of 71 OSAS patients and 34 age- and sex-matched controls. Erector spinae muscle thickness and subcutaneous fat were measured at the L1 vertebral level. Associations with clinical markers such as BMI, CRP, and oxygen saturation were examined. Results: OSAS patients had significantly greater muscle thickness and subcutaneous fat compared to controls (p < 0.01). Muscle thickness was positively correlated with BMI and waist circumference but inversely associated with CRP and oxygen saturation. Despite structural hypertrophy, these findings suggest impaired muscle quality and support the presence of sarcopenic obesity in OSAS. Conclusions: CT-based imaging provides valuable structural insights but may overestimate muscle function, particularly in obese OSAS patients. These results highlight the need to integrate imaging with functional assessments to accurately diagnose sarcopenia and guide individualized management strategies. Full article

While faba bean feeding improves grass carp muscle texture via reactive oxygen species (ROS), the main bioactive compound was unclear. In this study, vicine—a pro-oxidant glycoside—was isolated from faba beans using cation-exchange column chromatography and supplemented into the feed of grass carp at 0.6%. To assess the impact of vicine on muscle texture, the grass carp were fed for 150 days with three treatments: control group, faba bean group, and vicine group. The results showed that vicine improved muscle texture similarly to faba beans but caused fewer adverse effects on muscle, liver, and intestinal health. Vicine improved grass carp muscle texture in the following ways: (1) induced ROS overproduction, activating the Caspase apoptosis pathway and downregulating Pax-7 to promote satellite cell-mediated myofiber regeneration; (2) vicine-mediated intestinal microbiota alterations increased lipopolysaccharide (LPS) levels, indirectly elevating muscle ROS via the gut–muscle axis to further affect muscle structure. This study demonstrated that vicine improved muscle texture by activating ROS-dependent myofiber regeneration but also induced oxidative stress and gut microbiota perturbation. While vicine mitigated the severe toxicity of faba beans, its application requires careful evaluation of its toxicological properties to balance benefits and risks. This study offers new insights for enhancing the quality of aquatic animals. Full article

Muscle atrophy, characterized by progressive loss of skeletal muscle mass and strength, remains a significant therapeutic challenge. Jakyak-gamcho-tang (JGT) is a traditional herbal formulation that has demonstrated promising muscle-protective effects; however, the key bioactive constituents and the influence of different extraction methods have not yet been fully elucidated. This study compared the muscle-protective effects of the ethanol and water extracts of JGT (JGT-E and JGT-W, respectively), while also identifying the principal bioactive compounds that contribute to the enhanced efficacy of JGT-E. An integrative methodological approach was adopted, incorporating transcriptomic profiling, network pharmacology analysis, antioxidant activity assays, and in vitro validation using C2C12 myoblasts and myotubes. This comprehensive investigation enabled a detailed assessment of the biological activities of both JGT-E and JGT-W. Transcriptomic analysis revealed that JGT-E significantly modulates key pathways involved in oxidative phosphorylation, mitochondrial biogenesis, and signaling cascades related to PGC-1α, mTORC1, and ERRα, while simultaneously inhibiting TGF-β-mediated muscle atrophic signaling. Functional assays demonstrated that under oxidative stress conditions, JGT-E preserved mitochondrial content more effectively, reduced reactive oxygen species levels, and enhanced both myoblast viability and myotube integrity. Network pharmacology analysis identified isoliquiritigenin, catechin, and glabridin as major bioactive compounds enriched in JGT-E, all of which play critical roles in mitigating oxidative stress and supporting mitochondrial function. These findings were further substantiated by antioxidant assays that confirmed the contribution of these compounds to the observed muscle-protective effects of JGT-E. Overall, JGT-E exhibited superior efficacy in preventing muscle atrophy compared to JGT-W, likely due to its enriched profile of potent bioactive constituents. These results highlight the critical role of extraction methods in herbal medicine research and support the potential of JGT-E as a promising candidate for the treatment of muscle atrophy. Full article