Search Results (97)

Excess post-exercise oxygen consumption (EPOC) reflects cardiorespiratory fitness, energy metabolism and the residual physiological effects of preceding exercise. We aimed to compare EPOC profiles of master swimmers across different age groups and performance levels. Fourteen male master swimmers performed a 200 m all-out front crawl and breath-by-breath gas exchange and their heart rates were recorded during exercise and for 5 min post-exercise. A single exponential regression model was fitted to the post-exercise oxygen uptake kinetics to determine the EPOC amplitude, time constant and time delay. The EPOC magnitude was calculated as the area under the oxygen uptake–time curve. Swimmers were grouped into younger vs. older and faster vs. slower clusters using the 50th percentile, and the associations between age, performance and physiological variables were examined. Older swimmers were slower and showed a lower peak oxygen uptake than their younger counterparts (213.9 ± 27.9 vs. 165.7 ± 24.9 s and 39.1 ± 4.8 vs. 50.2 ± 8.1 mL∙kg⁻¹∙min⁻¹; p < 0.05). Slower swimmers were older and displayed a lower EPOC amplitude than faster performers (69.8 ± 7.3 vs. 45.7 ± 1.7 years and 23.2 ± 4.0 vs. 36.8 ± 10.2 mL∙kg⁻¹∙min⁻¹; p < 0.05). Although many of the variables did not differ between groups, effect sizes were moderate to very large (except for time constant and time delay). The swimmers’ age related directly to their performance and inversely to their peak oxygen uptake, peak heart rate and EPOC amplitude, while performance presented inverse associations with peak oxygen uptake, peak heart rate, EPOC amplitude and EPOC magnitude (p < 0.05). Master swimmers of different ages and performance levels exhibited distinct EPOC characteristics, which may provide relevant information regarding the individualisation of training and recovery strategies in this population. Full article

The rapid expansion of commercial human spaceflight is forcing a re-examination of how we decide who is “fit to fly” in space. For more than six decades, astronaut selection has been dominated by government programmes employing stringent medical and psychological criteria designed to minimise risk for small cohorts undertaking long-duration, high-consequence missions. Contemporary standards such as NASA-STD-3001 reflect this paradigm, treating astronauts as highly trained national assets expected to perform reliably under extreme physiological and psychological stress. In contrast, commercial operators aim to fly large numbers of spaceflight participants with highly heterogeneous medical and psychological profiles, within regulatory frameworks that emphasise informed consent and currently impose very limited prescriptive health requirements on passengers. This review examines the evolution and structure of traditional astronaut selection, outlines emerging approaches to screening and certifying commercial spaceflight customers, and explores the conceptual and practical gap between “selection” and “screening”. Particular attention is given to the increasing relevance of behavioural and psychological risk in short-duration but high-stress commercial missions, where acute responses, passenger–crew interaction, and behavioural variability can influence safety, especially in mixed-capability crews. Drawing on agency standards, psychological selection research, and recent proposals for commercial medical guidelines, this paper proposes a risk-informed, mission- and role-specific framework that adapts lessons from government astronaut corps to the needs of commercial spaceflight. We argue that future practice must balance safety, inclusion, and commercial viability through proportionate, evidence-based risk management, supported by systematic data collection across government and commercial flights. Full article

Physiologically based pharmacokinetic (PBPK) models are widely used in the context of personalized medicine, as they allow for the evaluation of dosing schedules and routes of administration by predicting absorption, distribution, metabolism and excretion (ADME) of drugs in biological systems. Traditionally, PBPK models have been developed and applied at the population level, enabling the characterization of predefined cohorts, which remains limited in supporting true precision dosing. In this review, we explored the increasingly common shift from population-based to individual PBPK modelling, where individuals are modelled as virtual twins (VTs). Through the inclusion of additional patient-specific data, such as demographic, physiological, phenotypic and genotypic information, models can be personalized, moving beyond traditional one-size-fits-all strategies. Overall, incorporating individual patient data (e.g., septic, psychiatric, cardiac, or neonatal populations) improves model performance. Physiological parameters, particularly renal function, show strong potential given their role in drug elimination, while demographic variables enhance predictive accuracy in certain studies. In contrast, the benefits of including cytochrome P450 (CYP) phenotypic and genotypic data remain inconsistent. We further emphasize methodologies used to evaluate model performance, with a focus on clinical validation through comparisons between predicted and observed concentration-time profiles. Key challenges, including limited sample sizes and data availability, that may compromise predictive precision, are also discussed. Finally, we highlight the potential integration of PBPK-based VTs into broader digital twin frameworks as a promising path toward clinical translation, while acknowledging the critical barriers that must be addressed to enable routine clinical implementation. Full article

Semitransparent perovskite photovoltaic (sPV) covers offer an attractive route for agrivoltaics, but their spectrally selective transmittance must be validated on plants cultivated under panel or in simulated conditions. Here, an AVA–MAPI perovskite module transmission profile was replicated using a programmable multi-channel LED platform and compared with a Reference McCree-adapted LED spectrum at identical photon flux density. Two lettuce cultivars (Lactuca sativa L.; ‘Canasta’ and ‘Trocadero’) were grown hydroponically in a light-sealed phytotron for 30 days (300 μmol m⁻² s⁻¹; 16/8 h photoperiod) under uniform temperature and humidity. Leaf gas exchange was quantified by fitting photosynthetic light-response curves, and plant performance was concurrently evaluated through growth metrics, biomass partitioning, and pigment-related traits (chlorophyll a/b, total carotenoids). The perovskite-emulated spectrum measurably reshaped net CO₂ assimilation across the PAR domain—yielding higher A_N at selected irradiances in post hoc contrasts—yet these physiological shifts did not translate into differences in leaf area, shoot or root biomass, or pigment concentrations—demonstrating spectral plasticity and agricultural compatibility of field-characterized perovskite transmission spectra. Overall, perovskite-emulated light sustained agronomically equivalent lettuce performance under moderate irradiance, supporting the feasibility of semitransparent perovskite PV covers, while underscoring the need for validation under natural sunlight. Full article

Background: Evidence on how physical and technical factors distinguish U-18 basketball levels is limited, yet these determinants may aid talent identification and development. This study examined differences in anthropometric, physical performance, and technical characteristics between high-level (HL; n = 38) and low-level (LL; n = 35) U-18 male basketball players and explored relationships between technical skills and key physical attributes across all participants. Methods: Participants were evaluated across anthropometry, physical performance, and basketball-specific technical skills. Statistical analyses assessed between-group differences and correlations, with significance set at p ≤ 0.05. Results: Compared to LL players, HL players exhibited significantly superior physical attributes, including greater height (Cohen’s d = 0.67) and arm-span (d = 0.65), reduced body fat (d = −0.58), and advanced performance metrics (10 m-speed running (d = −0.78), 20 m-speed running (d = −0.93), flexibility (d = 1.26), counter-movement jump height (d = 1.27), intermittent endurance (d = 1.18)). Technical proficiency in tasks such as 10 m- and 20 m-speed dribbling, maneuver dribbling and defensive sliding was also significantly faster in the HL group (d = −0.96, d = −1.05, d = −1.87, and d = −1.14, respectively). Several anthropometric and performance variables were strongly correlated with technical skills, indicating their relevance for distinguishing competitive levels. Conclusions: These findings underscore the interplay of physical, technical, and performance factors in high-level youth basketball. Coaches may use this information to guide targeted training strategies that support talent identification, player development, and competitive success. Full article

Background: Precise measurement of resting energy expenditure (REE) is essential in the intensive care unit (ICU), where metabolic requirements evolve throughout the course of critical illness. Predictive equations frequently fail to capture this variability, and limited data describe phase-dependent changes in REE using indirect calorimetry (IC). This study aimed to evaluate phase-related variation in REE and metabolic phenotypes in mechanically ventilated adults and to identify clinical and physiological correlates of both absolute REE and REE normalized by ideal body weight (REE/IBW). Methods: We conducted an observational, retrospective cross-sectional study in two ICUs at different hospitals. A total of 149 mechanically ventilated adults with a valid IC measurement were included and classified by illness phase: acute (0–3 days), intermediate (4–14 days), or chronic (>14 days). Differences in metabolic and gas-exchange variables were assessed using ANOVA or Kruskal–Wallis tests. Two multivariable linear regression models were fitted, one using absolute REE and a second using REE/IBW, incorporating metabolic phenotype categories to account for body-size heterogeneity. Results: Metabolic profiles differed across illness phases. Median REE increased from the acute (1664 kcal/day) to the intermediate (1869 kcal/day) and chronic (2074 kcal/day; p = 0.024) phases. Hypometabolic profiles were more frequent in the acute phase (64%), whereas hypermetabolic profiles were more prevalent in later phases (48%). RQ values were higher in the chronic phase compared with the acute phase (median 0.99 vs. 0.80; p < 0.001). In multivariable analyses, illness severity scores showed weak or inconsistent associations with REE after adjustment for gas-exchange variables. VCO₂ was independently associated with absolute REE (adjusted R² = 0.83). In the REE/IBW model, VCO₂, RQ, BMI, and metabolic phenotype were associated with normalized energy expenditure, with higher adjusted R² (0.87) and lower prediction error metrics. Conclusions: Resting energy expenditure and metabolic phenotypes vary across phases of critical illness. Gas-exchange variables, particularly VCO₂, were more closely associated with measured energy expenditure than severity scores. Normalization of REE by ideal body weight reduced variability and improved model performance, highlighting the analytical value of indirect calorimetry for characterizing phase-dependent metabolic patterns in critically ill adults. Full article

WW-type super-female broodstock are essential for all-female breeding in sturgeons under the ZZ/ZW sex-determination system, but their practical use is constrained by high mortality. This study investigates the underlying physiological and molecular mechanisms contributing to the reduced viability of WW-type super-female sterlet (Acipenser ruthenus) by comparing three genotypes (ZZ, ZW and WW) in terms of survival rates, oxidative stress levels, and gonadal gene expression. F₂ gynogenetic diploid juvenile sterlet with three genotypes were reared for 100 days under controlled conditions. Survival rates were recorded, and oxidative stress markers, including SOD, CAT, MDA and GSH-Px, were measured using commercially available assay kits. Gonadal gene expression profiles were analyzed using transcriptomic analysis. The results revealed that WW-type juveniles exhibited a significantly lower survival rate (64.2%) compared to ZZ-type and ZW-type fish (both 94.2%, p < 0.0001). While hepatic SOD and CAT activities did not differ among genotypes, MDA and GSH-Px levels were significantly higher in WW-type fish, suggesting enhanced lipid peroxidation and an insufficient compensatory antioxidant response. Transcriptome analysis revealed 747 significantly differentially expressed genes between WW-type super-females and normal ZZ/ZW individuals (p < 0.05), with significant enrichment in pathways related to immune regulation, receptor activity, lipid metabolism, and ferroptosis. Notably, downregulation of arachidonic acid metabolism genes (PTGS2, PTGES, PTGDS) was observed, while ferroptosis-related genes GPX4 and SLC3A2 were upregulated, suggesting that disturbed arachidonic acid metabolism, along with lipid peroxidation and ferroptosis activation, contribute to the reduced survival of WW-type super-females. These findings provide integrative physiological and transcriptomic evidence for the mechanistic basis of poor fitness in gynogenetic WW-type super-females and offer foundational data for improving the feasibility of all-female breeding in sturgeon. Full article

Drought responses in poplar are genotype-dependent, yet standardized metrics for quantifying drought tolerance remain scarce. Here, we employed logistic modeling of relative electrolyte leakage (REC) for the first time in poplar to derive clone-specific semi-lethal polyethylene glycol (PEG) concentrations (LC₅₀), transforming a traditional descriptive assay into a quantitative, high-throughput drought-injury metric. Six elite Populus cultivars were exposed to increasing PEG concentrations, and their REC curves were fitted using a logistic function (R² = 0.885−0.981). The derived semi-lethal PEG concentration (LC₅₀) ranged from 7.99% in ‘PZ1’ (drought-sensitive, SS) to 13.44% in ‘YX2’ (drought-tolerant, ST), enabling clear classification. Under 10% PEG stress, ST maintained leaf water content (LWC) at 73%, while SS dropped to 63%. Malondialdehyde (MDA) content doubled in SS (44.7 nmol·g⁻¹ FW) but increased by only 25% in ST (33.5 nmol·g⁻¹ FW). Gas exchange analysis revealed that SS exhibited approximately twice the reduction in net photosynthetic rate (Pn), transpiration rate (Tr), and stomatal conductance (Gs) compared to ST, with intercellular CO₂ accumulation (Ci) occurring only in SS—indicating both stomatal and non-stomatal limitations. Osmolyte profiling showed that SS accumulated large amounts of soluble sugars (Ss) (+128%) and proline (Pro) (+230%), whereas ST maintained stable soluble protein (Sp) levels and only moderately increased proline (+120%). Antioxidant capacity differed markedly: catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD) activities increased by 5.6-, 1.8-, and 2.0-fold in ST, respectively, compared to 3.4-, 1.3-, and 1.7-fold in SS. Principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) of ten physiological traits explained 89% of the total variance (R²X = 0.954, Q² = 0.973), identifying POD, SOD, CAT, and Pro as the most discriminative variables (VIP > 1). This four-marker signature converts a conventional dose–response assay into a rapid, low-cost screening module that can be deployed in robotic phenotyping platforms. Specifically, the high-ranking genotype ‘YX2’ is recommended for immediate use in water-limited plantations and as a robust parent for next-generation dryland breeding programs. Full article

An integrated physiological model would be useful for monitoring internal load in functional fitness, including formats like CrossFit and Hyrox. Traditional performance metrics often neglect internal strain, energy system engagement, and neuromuscular fatigue, central to these modalities. Oxygen uptake kinetics, metabolic profiling, heart rate and heart rate variability monitoring, and neuromuscular fatigue assessment can be employed for load monitoring. Breath-by-breath oxygen uptake analysis characterizes aerobic activation and recovery. Metabolic stress is estimated via indirect calorimetry and capillary blood lactate to quantify oxidative, glycolytic, and phosphagen contributions. Heart rate is tracked continuously to assess session intensity, while heart rate variability provides insights into autonomic recovery. Neuromuscular fatigue can be assessed via countermovement jump performance, offering sensitive measures of recovery and training tolerance. Portable tools such as the Cosmed K5™, Lactate Pro 2, heart rate sensors, and force platforms support real-time monitoring in training and competitions. Rather than advocating for the continuous use of advanced tools, the model promotes strategic integration of high-precision methods for research, and practical, low-cost alternatives (e.g., heart rate monitoring, session rating of perceived exertion, or jump analysis apps) for day-to-day coaching. This approach enables early detection of maladaptation, supports individualized training adjustments, and improves safety and performance outcomes. Ultimately, this framework bridges physiological science and real-world practice, providing value across both applied and research settings. Full article

Training on deep sand is commonly employed in endurance horses, but its physiological adaptation remains poorly characterized. This study aimed to characterize locomotor adaptations during a 7 km controlled-speed canter on deep sand in eighteen endurance horses, to identify heart rate variability (HRV) components, and to investigate changes in hematological variables before and after exercise. Stride frequency (SF) and stride length (SL), HRV, and hematological profiles were recorded during exercise and recovery with a fitness tracker. Associations between maximum speed and locomotor parameters were assessed by linear regression, while Pearson’s correlation assessed HRV relationships, also with physiological parameters. Hematological parameters were assessed with paired t-test before and after training. SL percentage change was the strongest predictor of speed (β = 0.677). HRV analysis revealed delayed parasympathetic reactivation; the parasympathetic recovery index (PNS REC) was correlated with mean RR interval on the ECG (r = 0.968) and heart rate (r = −0.964) during recovery. Post-exercise rectal temperature showed correlations with HRV recovery indices. Hematological evaluation revealed post-exercise increases in red blood cell count, hematocrit, hemoglobin, and corpuscular indices. SL plays a predominant role in achieving higher speeds on deep sand, while PNS REC emerges as a practical and accessible marker of autonomic recovery and fatigue. Horses with enhanced thermoregulation recover better. Hematological results confirm a physiological stress response that may optimize oxygen delivery. Integrating locomotor, cardiovascular, and hematological monitoring may improve management and welfare in endurance training. Full article

The human lower extremity plays a vital role in locomotion, posture, and weight-bearing through coordinated motion at the hip, knee, and ankle joints. These joints facilitate essential functions including flexion, extension, and internal and external rotation. To address mobility impairments through personalized therapy, this study presents the design, dynamic modeling, and control of a four-degree-of-freedom (4-DOF) lower limb exoskeleton robot. The system actuates hip flexion–extension and internal–external rotation, knee flexion–extension, and ankle dorsiflexion–plantarflexion. Anatomically aligned joint axes were incorporated to enhance biomechanical compatibility and reduce user discomfort. A detailed CAD model ensures ergonomic fit, modular adjustability, and the integration of actuators and sensors. The exoskeleton robot dynamic model, derived using Lagrangian mechanics, incorporates subject-specific anthropometric parameters to accurately reflect human biomechanics. A conventional sliding mode controller (SMC) was implemented to ensure robust trajectory tracking under model uncertainties. To overcome limitations of conventional SMC, an adaptive sliding mode controller with boundary layer-based chattering suppression was developed. Simulations in MATLAB/Simulink 2025 R2025a demonstrate that the adaptive controller achieves smoother torque profiles, minimizes high-frequency oscillations, and improves tracking accuracy. This work establishes a comprehensive framework for anatomically congruent exoskeleton design and robust control, supporting the future integration of physiological intent detection and clinical validation for neurorehabilitation applications. Full article

Background: Burning Mouth Syndrome (BMS) is a nociplastic pain condition characterized by altered central nervous system pain processing, significantly impacting patient quality of life. Pharmacological management often involves amitriptyline (monotherapy) and aripiprazole (for refractory cases) in Japan. However, the therapeutic efficacy of these drugs in BMS frequently exhibits a non-sigmoid (U-shaped or bell-shaped) dose–response relationship, indicating a clinically effective dose that is often considerably lower than those used for their primary indications and challenging conventional pharmacological assumptions. Method: This paper synthesizes existing pharmacological knowledge to elucidate the mechanisms underlying the non-dose-dependent actions of amitriptyline and aripiprazole in BMS. It focuses on their specific interactions with key neurotransmitter systems and receptors, particularly N-methyl-D-aspartate (NMDA) receptors and dopamine D2 receptors, to explain the observed non-linear dose–response and the importance of identifying a personalized therapeutic window. Result: Amitriptyline demonstrates efficacy in BMS at low doses (e.g., 25 mg), primarily through its action as an NMDA receptor antagonist via calcium-dependent desensitization and open-channel block, addressing central sensitization. Its effects are distinct from its antidepressant actions, and the “serotonin paradox” highlights the complexity of serotonin’s role in pain. Aripiprazole, utilized for refractory BMS, acts as a dopamine D2 receptor partial agonist, leading to a non-linear dose–response where sustained therapeutic effect is observed at specific low doses (e.g., 1.7–1.8 mg/day). This non-linearity is attributed to partial agonism, alongside interactions with serotonin 5-HT1A and 5-HT2A receptors. The general non-dose-dependency for both drugs is further explained by phenomena such as multiple binding sites with differing affinities, receptor desensitization/downregulation, activation of counter-regulatory mechanisms, and hormesis. Discussion: The observed non-linear dose–response curves for amitriptyline and aripiprazole in BMS underscore the inadequacy of a “one-size-fits-all” treatment approach. This necessitates a shift towards personalized medicine, which considers individual patient factors including pharmacogenomics, comorbidities, age, organ function, and psychological/social profiles. The true “personalized therapeutic window” is a balance between achieving significant pain relief and minimizing adverse effects, emphasizing careful titration and patient-centered care. Conclusions: The pharmacological actions of amitriptyline and aripiprazole in BMS are not linearly dose-dependent, but rather exhibit a personalized therapeutic window driven by complex interactions with NMDA and D2 receptors and adaptive physiological responses. This intricate pharmacological landscape mandates a personalized medicine approach to optimize treatment outcomes, improve patient adherence, and enhance the quality of life for individuals suffering from this challenging nociplastic pain condition. Full article

CrossFit performance is influenced by physiological, neuromuscular, and perceptual factors, yet the extent to which these determinants vary by sex or training experience in standardized CrossFit Workouts of the Day (WODs) remains unclear. This study examined whether variables such as lactate accumulation, oxygen uptake dynamics, jump performance loss, and ventilatory responses relate differently to performance when stratified by sex and expertise. Fifteen trained athletes (eight males, seven females; overall mean age 27.7 ± 4.6 years) took part. Assessments included body composition, squat (SJ) and countermovement jumps (CMJ), and maximal oxygen consumption [VO₂max]. On a separate day, they performed Fran (21-15-9 thrusters and pull-ups, Rx or scaled) The prescribed (‘Rx’) version used standardized barbell loads (43 kg for men, 29 kg for women), while the scaled version involved reduced loads or pull-up modifications. Respiratory gas exchange and heart rate were continuously monitored, while blood lactate and jump performance were measured pre- and post-WOD. Workout completion time [s] was the primary outcome. Correlation heatmaps explored associations in the overall sample and by sex and expertise. Mean completion time was 422.1 ± 173.2 s (range: 200–840). Faster performance correlated with higher ventilatory responses [ΔVe, r = −0.60, p = 0.018], greater mean VO₂ (r = −0.62, p = 0.014), superior jump power [CMJ pre, r = −0.65, p = 0.009], and higher post-WOD lactate [r = −0.54, p = 0.036]. Sex-stratified analyses showed that males relied on ventilatory efficiency and neuromuscular power, whereas females were more constrained by performance loss and higher resting perceived exertion (RPE). Experts depended on ventilatory and neuromuscular efficiency, while initiates showed stronger associations with decrements in jump performance and higher RPE. These findings highlight subgroup-specific performance profiles and reinforce the need for tailored training strategies in CrossFit athletes. Full article

Background: The multifactorial nature of CrossFit performance remains incompletely understood, particularly regarding sex- and experience-related physiological and biomechanical factors. Methods: Fifteen trained athletes (8 males, 7 females) completed assessments of anthropometry, estimated one-repetition maximums (bench press, back squat, deadlift), squat jump (SJ), maximal oxygen uptake (VO₂max), ventilatory responses ($\dot{\mathrm{V}}$E), and heart rate (HR). Spearman, Pearson, and partial correlations were calculated with Holm and false discovery rate (FDR) corrections. Results: Males displayed greater body mass, lean and muscle mass, maximal strength, and aerobic capacity than females (all Holm-adjusted p < 0.01). Experienced athletes completed Fran faster than beginners despite broadly similar anthropometric and aerobic profiles. In the pooled sample, WOD time showed moderate negative relationships with estimated 1RM back squat (ρ = −0.54), deadlift (ρ = −0.56), and bench press (ρ = −0.65) before correction; none remained significant after Holm/FDR adjustment, and partial correlations controlling for training years were further attenuated. Conclusions: This exploratory study provides preliminary evidence suggesting that maximal strength may contribute to Fran performance, whereas conventional aerobic measures were less influential. However, given the very small sample (n = 15, 8 males and 7 females) and the fact that no relationships remained statistically significant after correction for multiple testing, the results must be regarded as preliminary, hypothesis-generating evidence only, requiring confirmation in larger and adequately powered studies. Full article

Background: Basketball is characterized as a high-intensity, intermittent sport that places considerable demands on the cardiorespiratory, neuromuscular, and mechanical systems. These physiological requirements are modulated by contextual variables and the athlete’s stage of biological maturation, both of which significantly influence physical fitness outcomes. Consequently, it is imperative to employ age- and development-specific assessment protocols. Objectives: This study aimed to evaluate the differences in physical fitness across competitive categories and to explore the interrelationships among the various physical assessment tests. Twenty-four male players (U14 = 12; U16 = 12) participated in this research. Methods: Athletes were monitored using WIMUPRO inertial measurement units and completed the SBAFIT test battery to evaluate physical fitness parameters. Statistical analyses included both inferential and correlational approaches, with effect sizes calculated for all relevant variables. The independent variable was the competitive age category of the players. Results: The results indicated notable differences in physical performance between developmental groups, primarily attributed to biological maturation. Significant disparities were observed in measures of aerobic capacity, linear speed, agility, and centripetal force. Conclusions: The comparative nature of this study across developmental categories offers novel insights and practical implications for talent development and training optimization. Full article