Search Results (539)

Aim: This study analyzed the concurrent validity of the Optojump infrared photocell system for estimating lower limb peak power by comparing it with the 15 s Wingate anaerobic test (WAnT) and examining relationships with sprint performance indicators. Methods: Twelve physically active university students (ten males, two females; age: 23.39 ± 1.47 years; body mass: 73.08 ± 9.19 kg; height: 173.67 ± 6.97 cm; BMI: 24.17 ± 1.48 kg·m⁻²) completed a cross-sectional validation protocol. Participants performed WAnT on a calibrated Monark ergometer (7.5% body weight for males, 5.5% for females), 30 s continuous jump tests using the Optojump system (Microgate, Italy), and 30 m sprint assessments with 10 m and 20 m split times. Peak power was expressed in absolute (W), relative (W·kg⁻¹), and allometric (W·kg^−0.67) terms. Results: Thirty-second continuous jump testing produced systematically higher peak power values across all metrics (p < 0.001). Mean differences indicated large effect sizes: relative power (Cohen’s d = 0.99; 18.263 ± 4.243 vs. 10.99 ± 1.58 W·kg⁻¹), absolute power (d = 0.86; 1381.71 ± 393.44 vs. 807.28 ± 175.45 W), and allometric power (d = 0.79). Strong correlations emerged between protocols, with absolute power showing the strongest association (r = 0.842, p < 0.001). Linear regression analysis revealed that 30 s continuous jump-derived measurements explained 71% of the variance in Wingate outcomes (R² = 0.710, p < 0.001). Sprint performance showed equivalent predictive capacity for both tests (Wingate: R² = 0.66; 30 s continuous jump: R² = 0.67). Conclusions: The Optojump infrared photocell system provides a valid and practical alternative to laboratory-based ergometry for assessing lower limb anaerobic power. While it systematically overestimates absolute values compared with the Wingate anaerobic test, its strong concurrent validity (r > 0.80), large effect sizes, and equivalent predictive ability for sprint performance (R² = 0.66–0.71) confirm its reliability as a field-based assessment tool. These findings underscore the importance of sport-specific, weight-bearing assessment technologies in modern sports biomechanics, providing coaches, practitioners, and clinicians with a feasible method for monitoring performance, talent identification, and training optimization. The results further suggest that Optojump-based protocols can bridge the gap between laboratory precision and ecological validity, supporting both athletic performance enhancement and injury prevention strategies. Full article

Cardiopulmonary Exercise Testing (CPET) is the gold standard for the functional assessment in patients with heart failure (HF), providing objective parameters that reflect the integrated response of the cardiovascular, respiratory, and muscular systems, in addition several CPET-derived variables have shown independent prognostic value in patients with both reduced (HFrEF) and preserved ejection fraction (HFpEF) HF. This review aims to critically analyze the main CPET prognostic variables in heart failure, highlighting their underlying pathophysiological mechanisms, their predictive capacity for mortality and hospitalizations, and their integration into clinical decision-making models. Parameters such as peak oxygen uptake (VO₂), minute ventilation/carbon dioxide production (VE/VCO₂) slope, periodic breathing (or exercise oscillatory ventilation—EOV), anaerobic threshold (AT), oxygen pulse, and VO₂/work slope provide complementary insights into clinical risk; moreover, the combination of multiple CPET variables allows for more accurate risk stratification compared to the isolated use of each parameter. Multiparametric prognostic models such as the Metabolic Exercise Cardiac Kidney Index (MECKI) score, the Seattle Heart Failure Model, and the Heart Failure Survival Score (HFSS) incorporate these variables alongside clinical and laboratory data to guide advanced management and therapeutic decisions, including heart transplantation or left ventricular assistant device (LVAD) implantation. For these reasons, CPET-derived variables are essential prognostic tools in heart failure. Beyond improving risk stratification, their integration into multiparametric models supports a more personalized therapeutic approach, including tailored pharmacological management. Full article

Global food systems face growing pressure from population expansion and climate change, making the identification of resilient crops a priority. The nopal cactus (Opuntia spp.) stands out for its capacity to thrive in arid environments and for its cultural and economic importance in Mexico. This study analyzes worldwide research trends and evaluates evidence from Mexico to identify opportunities and strategies for closing production cycles through residue valorization. Scientific output over the past decade shows steady growth and a thematic transition from basic agronomic and compositional studies toward sustainability, bioactive compounds, and circular economy approaches. In the Mexican context, applied studies demonstrate that Opuntia spp. cladodes residues can be transformed into composts with C/N ratios between 12 and 26, improving soil organic matter and nutrient availability. Biofertilizers produced through anaerobic fermentation enhanced phosphorus solubility in alkaline soils, while direct residue incorporation increased carrot and tomato yields up to threefold. Farmers recognize these practices as low-cost and compatible with local systems. Nevertheless, the lack of standardized protocols and scalable models limits widespread adoption. Strengthening research collaboration, policy incentives, and technology transfer could position Mexico as a leader in sustainable Opuntia value chains and advance circular economy practices in smallholder farming systems. Full article

This study examined the physiological and performance adaptations of association football (soccer) players during a six-week transitional (off-season) period following the competitive season through a remotely supervised, periodized training program. Fifteen male players (19.57 ± 1.14 years; training experience: 13.60 ± 1.81 years) from the Greek Super League 2 completed pre- and post-intervention laboratory assessments, including anthropometry, cardiopulmonary function, isokinetic strength, and jump performance. The program integrated high-intensity interval training, aerobic conditioning, and individualized resistance training, adjusted according to test results. Anthropometric parameters remained stable. Maximal oxygen uptake (VO₂max) increased significantly by 2.8% (56.31 ± 3.87 vs. 57.91 ± 3.02 mL/kg/min), while anaerobic threshold time and velocity declined by 6.2% (472.87 ± 35.06 vs. 443.33 ± 24.69 sec) and anaerobic threshold velocity fell by 6.1% (15.97 ± 1.17 vs. 15.00 ± 0.91 km/h), indicating a partial preservation of aerobic capacity but reductions in submaximal endurance. Isokinetic strength of the quadriceps and hamstrings was maintained across angular velocities, but squat jump height decreased significantly by 4.3% (p = 0.033), suggesting a loss of concentric-only explosive power despite stable countermovement jump performance. These findings indicate that targeted off-season training can maintain overall physical readiness, body composition, and VO₂max, but may require additional endurance and concentric power elements to preserve all performance qualities essential for the competitive season. Overall, the program effectively preserved most performance variables with only minor decrements, representing a favorable outcome for the off-season; however, if greater asymmetries, deficits, or other training targets are identified, more specific adjustments to training intensities, such as the inclusion of additional endurance and concentric-only power elements, may be required to achieve significant improvements. Full article

High-Intensity Functional Training (HIFT) is a training method that has garnered increasing attention due to the rise in hybrid competitions such as CrossFit or Hyrox, a race format combining strength and endurance tasks in a fixed structure. Therefore, an integrative approach is needed to help us understand which physiological capacities this training method enhances. Objectives: This scoping review aimed to map the current scientific literature related to HIFT, with a particular focus on physiological and psychobiological determinants of performance in hybrid competition contexts. Methods: Following the methodological framework of Arksey and O’Malley and the PRISMA-ScR guidelines, a systematic search was conducted in Web of Science, Scopus, and PubMed. Thirty-nine studies published between 2015 and 2025 were included. Results: HIFT was found to improve key physical attributes such as aerobic capacity, muscular strength, anaerobic power, and fatigue tolerance. Increases in VO₂max ranging from 8% to 15% and strength gains of 10% to 20% in major lifts were commonly reported. Improvements in local muscular endurance, power output, and recovery capacity were also observed. The physiological benefits appeared more pronounced in trained individuals, especially those with greater resistance training volume. In addition, psychobiological responses, including perceived exertion, cognitive control, and motivation, were explored in several studies, with more experienced athletes showing higher fatigue tolerance and better performance consistency under stress. Conclusions: HIFT enhances essential physical attributes applicable to hybrid events. The findings support the use of HIFT as a foundational method for training athletes involved in demanding multi-domain fitness settings, without attributing these benefits specifically to any single competitive event. Full article

Anaerobic digestion (AD) is a mature industrial fermentation technology for converting organic matter into renewable bioenergy, and chicken manure (CM) is a promising feedstock due to its high organic content. However, the industrial-scale AD of CM is often hindered by ammonium inhibition, particularly under high organic loading rates (OLRs). Biochar has emerged as a sustainable additive that can enhance microbial activity, buffer pH, and improve system stability. In this study, the effects of biochar on the methane production and fermentation performance of CM in terms of AD were evaluated under both batch and continuous conditions, where batch experiments were conducted at different biochar-to-CM ratios. Ammonium nitrogen and methane production were monitored to determine the optimal biochar addition ratio. Continuous stirred-tank reactors (CSTRs) were then operated with the optimal biochar addition ratio under stepwise-increasing OLR conditions to assess methane production, fermentation parameters, and methanogen community composition. The results showed that an optimal biochar addition of 9% reduced total ammonium nitrogen (TAN) by 31.75% and increased cumulative methane production by 25.93% compared with the control. In continuous operation, biochar addition mitigated ammonium inhibition, stabilized pH, enhanced system stability and organic loading capacity, and improved methane production by 21.15%, 27.78%, and 83.33% at OLRs of 2.37, 4.74, and 7.11 g volatile solids (VS)/(L·d), respectively, compared to the control. Biochar also inhibited the growth of methylotrophic methanogen of RumEn_M2. These findings provide scientific and technical support for applying biochar as a process enhancer during the AD of CM. Full article

This study investigated the influence of aerobic capacity on lactate clearance rate and heart rate recovery during ice hockey matches. Considering the growing intensity and anaerobic demands of modern ice hockey, the ability to recover quickly between high-intensity shifts is essential for optimal performance. Thirty-eight amateur ice hockey players (age: 35 ± 5 years; VO₂max: 48.93 ± 3.88 mL·min⁻¹·kg⁻¹) from the Silesian Amateur Hockey League underwent laboratory ramp tests to determine VO₂max, followed by on-ice repeated sprint tests and heart rate monitoring during matches. The results demonstrated significant positive correlations between VO₂max and lactate clearance (ΔLa4–8min [mmol/L]= 2.55 ± 0.58 mmol·L⁻¹; rho = 0.545; p < 0.001), as well as heart rate recovery (Δ%HRmax = 25.88 ± 2.09%; rho = 0.682; p < 0.001). Players with higher VO₂max exhibited a faster reduction in heart rate during recovery periods between shifts and maintained better sprint performance (rho = –0.877; p < 0.001). These findings confirm that higher aerobic capacity enhances both metabolic and autonomic recovery processes, enabling players to sustain high-intensity efforts more effectively during the game. The study highlights the importance of developing aerobic fitness in hockey training to improve recovery efficiency and match performance. Full article

The increasing generation of agricultural waste poses both environmental and economic challenges, particularly in rural areas with limited infrastructure. Anaerobic digestion has emerged as a sustainable alternative, enabling the valorization of waste and the production of biogas and biofertilizer. This study evaluated the economic and environmental gains of mono- and co-digestion of equine manure and vegetable waste using biodigesters of different capacities across four simulated projects—Project 1 (15 m² biodigester with monodigestion), Project 2 (15 m² biodigester with co-digestion), Project 3 (20 m² biodigester with monodigestion), and Project 4 (20 m² biodigester with co-digestion). Economic feasibility was assessed through indicators such as Net Present Value (NPV), Internal Rate of Return (IRR), Modified IRR (MIRR), Profitability Index (PI), Benefit-Cost Ratio (B/C), Discounted Payback Period, sensitivity analysis, and Monte Carlo simulation, adopting a Minimum Attractiveness Rate (MAR) of 6.43% per year. Environmental benefits were estimated based on the annual reduction of CO₂ equivalent emissions. The results showed that all projects were economically viable and had the potential to mitigate up to 36 tons of CO₂eq per year. Additionally, an eco-efficiency indicator (NPV per CO₂eq avoided) was calculated to enable an integrated assessment of economic performance and environmental impact. Projects using 20 m³ biodigesters achieved the best results, with Project 3 being the most eco-efficient (USD256.05/tCO₂eq), while Project 4 yielded the highest absolute return in all economic analysis tools: NPV (USD 9063.81), IRR (25.10%), MIRR (10.95%), PI (USD 1.65), B/C (USD 1.65) and DPP (4.56 years). The integrated analysis underscores the significance of co-digestion and economies of scale in encouraging the adoption of this technology by small rural producers. Full article

Background: Mixed martial arts (MMA) requires athletes to generate repeated bursts of high-intensity effort with minimal recovery time. Despite the sport’s reliance on anaerobic power, there are minimal data assessing pre-competition physiological capacity in MMA fighters. This study aimed to evaluate anaerobic performance using the Wingate Anaerobic Test (WAnT) and Countermovement Jump (CMJ) in professional MMA athletes, and to examine relationships between performance metrics across weight classes. Methods: Twelve professional male MMA fighters (age 29.00 ± 4.80 years, weight 85.60 ± 13.90 kg) completed both CMJ and WAnT assessments using sensor-integrated devices (Just Jump mat and Wattbike Pro). CMJ height and WAnT variables (peak power, average power, and fatigue index) were measured. Pearson correlations were used to examine the relationships between CMJ and Wingate outputs. Independent t-tests compared performance between lighter (<83.9 kg) and heavier (≥83.9 kg) weight groups. Results: CMJ performance showed significant positive correlations with both average power (r = 0.71, p < 0.001) and peak power (r = 0.61, p = 0.004). Peak power was also positively correlated with fatigue index (r = 0.84, p < 0.001), suggesting greater fatigue in higher power-producing athletes. Finally, the heavier weight group of fighters produced significantly (p = 0.03) more peak power when compared to the lighter weight group. Conclusions: The findings support the use of CMJ and WAnT testing as practical tools for evaluating anaerobic performance in MMA athletes. These assessments can help guide individualized training strategies, particularly when accounting for weight group specific differences in power and fatigue dynamics. Full article

Accurate assessment of cardiorespiratory fitness (CRF) in adolescents is critical. However, normalizing oxygen consumption (VO₂) to body mass (BM) may underestimate CRF in overweight (OW) youth by including metabolically inactive fat mass. This study examined differences in VO₂ normalized by BM and fat-free mass (FFM) between normal weight (NW) and OW adolescents. Thirty-eight participants (19 NW, 19 OW; 12–17 years) underwent anthropometric, body composition, and cardiorespiratory fitness assessments. VO₂ at the aerobic threshold (VO₂AerT), anaerobic threshold (VO₂AnT), and peak exercise (VO₂peak) were measured and expressed in absolute terms and relative to BM and FFM. Group differences in the main outcomes were analyzed using a one-way ANOVA, and Pearson correlation was used to examine associations between VO₂, BM and FFM. When normalized by BM, NW adolescents showed significantly higher VO₂AerT (18.7 ± 3.6 vs. 14.5 ± 2.3), VO₂AnT (28.8 ± 6.3 vs. 23.6 ± 4.7), and VO₂peak (37.7 ± 6.7 vs. 29.1 ± 7.0) compared to OW peers (p < 0.05). No significant differences were found when VO₂ values were normalized by FFM. A group difference was observed in the VO₂peak vs. BM slope (p = 0.03) but not in the VO₂peak vs. FFM slope. FFM normalization provides a more accurate assessment of CRF by accounting for differences in body composition, underscoring the importance of evaluating the aerobic capacity of metabolically active tissue rather than total body weight in youth populations. Full article

Background: This study examined the impact of aerobic capacity on force–velocity (F–v) variables and repeated-sprint (RS) performance in male national-level sprinters (SPRs, n = 8; 177.0 ± 4.3 cm; 74.0 ± 5.0 kg; maximal oxygen uptake [VO₂max]: 55.4 ± 3.0 mL/kg/min) and middle-distance runners (MDRs; n = 8; 179.0 ± 5.1 cm; 67.2 ± 5.0 kg; VO₂max: 64.3 ± 3.3 mL/kg/min). Method: Participants underwent assessments of aerobic capacity, mechanical F-v profiling in sprinting 2 × 60 m with full recovery, and a 10 × 60 m repeated-sprint test with 30 s recovery. Results: MDRs exhibited significantly higher VO₂max (p < 0.001) and speed at VO₂max (vVO₂max, p < 0.001), while SPRs demonstrated greater anaerobic speed reserve (ASR, p < 0.001), maximal theoretical horizontal force (F₀, p = 0.012), and power output (P_max, p < 0.01). During the RS test, SPRs displayed a 16.6% performance decrement (p = 0.002) and failed to complete all sprints with voluntary withdrawal after 5–8 sprints due to exhaustion, whereas MDRs maintained consistent performance. SPRs exhibited a larger decrease in v₀ compared to MDRs (p < 0.01), whereas no differences were observed on F₀ (p = 0.519) and P_max (p = 0.758). Blood lactate accumulation was higher in SPRs (p < 0.001). Multiple linear regression analysis on the pooled sample identified vVO₂max (p = 0.003) and not ASR (p = 0.482) as a key predictor of fatigue resistance. Conclusions: These findings underscore the critical role of aerobic capacity in sustaining RS performance. Aerobic capacity, specifically vVO₂max, emerged as the primary determinant of fatigue resistance during repeated sprints, underscoring its critical role in sustaining RS performance over mechanical variables such as v₀ but not F₀ and P_max. Full article

The circadian rhythm controls the sleep/wake cycle and a wide variety of metabolic and physiological functions. Clock genes regulate it in response to both external and endogenous stimuli, and their expression may change because of aging, leading to an increased risk of health problems. Despite the well-described benefits of physical exercise as a circadian synchronizer, there is a lack of literature regarding the role of chronic exercise intensity in clock gene expression during aging. This article aims to analyze the differential expression of genes that regulate the biological clock under the effects of variable-intensity aerobic swimming training in aging mice, determining whether these exercise regimens interfere with the genomic regulation of the circadian rhythm. For this purpose, the mice were exposed to low- and high-intensity exercise and had their heart and gastrocnemius tissues molecularly analyzed by cDNA synthesis and qPCR to determine the expression levels of the selected genes: Clock, Arntl, Per1, Per2, Cry1, Cry2, and Nr1d1. The results showed that low-intensity exercise, performed at workloads below the anaerobic threshold, significantly changed their expression in the gastrocnemius muscle (p < 0.05), while high-intensity exercise had no statistically significant effects (p > 0.05), with the heart being immune to exercise influence except when it comes to the Per1 gene, for which expression was increased (p = 0.031) by low-intensity exercise. Additionally, both body weight and lactate thresholds had no change during the experiment (p > 0.05), while the maximum supported workload was maintained for high-intensity exercise (p > 0.05) and increased for low-intensity exercise (p < 0.01), with the control group experiencing a decay instead (p < 0.05). Thus, the present study highlights the importance of chronic exercise in modulating clock genes and opens exciting possibilities for circadian medicine, such as improvements in exercise capacity, heart condition, and lipid metabolism for subjects of low-intensity regimens. Full article

This two-part study assesses the impact of biogas inhibition on large-scale waste-to-energy anaerobic digestion (WtE-AD) plants through techno-economic and life cycle assessment approaches. The first part addresses technical and economic aspects. An anaerobic co-digestion system using vegetable waste (FVW) and meat waste (MW) was operated at laboratory scale in a semi-continuous regime with daily feeding to establish a stable process and induce programmed failures causing methanogenic inhibition, achieved by removing MW from the reactor feed and drastically reducing the protein content. Experimental data, combined with bioprocess scale-up models and cost engineering methods, were then used to evaluate the effect of inhibition periods on the profitability of large-scale WtE-AD processes. In the experimental stage, the stable process achieved a yield of 521.5 ± 21 mL CH₄ g⁻¹ volatile solids (VS) and a biogas productivity of 0.965 ± 0.04 L L⁻¹ d⁻¹ (volume of biogas generated per reactor volume per day), with no failure risk detected, as indicated by the volatile fatty acids/total alkalinity ratio (VFA/TA, mg VFA L⁻¹/mg L⁻¹) and the VFA/productivity ratio (mg VFA L⁻¹/L L⁻¹ d⁻¹), both recognized as effective early warning indicators. However, during the inhibition period, productivity decreased by 64.26 ± 11.81% due to VFA accumulation and gradual TA loss. With the progressive reintroduction of the FVW:MW management and the addition of fresh inoculum to the reaction medium, productivity recovered to 96.7 ± 1.70% of its pre-inhibition level. In WtE-AD plants processing 60 t d⁻¹ of waste, inhibition events can reduce net present value (NPV) by up to 40.2% (from 0.98 M USD to 0.55 M USD) if occurring once per year. Increasing plant capacity (200 t d⁻¹), combined with higher revenues from waste management fees (99.5 USD t⁻¹) and favorable electricity markets allowing higher selling prices (up to 0.23 USD kWh⁻¹), can enhance resilience and offset inhibition impacts without significantly compromising profitability. These findings provide policymakers and industry stakeholders with key insights into the economic drivers influencing the competitiveness and sustainability of WtE-AD systems. Full article

Staphylococcus aureus is a leading cause of skin and soft tissue infections (SSTIs), yet the bacterial genomic adaptations underlying the transition from nasal colonization to invasive infection remain incompletely defined. We sequenced and analyzed 157 S. aureus isolates (126 from SSTIs and 31 from asymptomatic nasal colonization) from a primary care network in South Texas. Using genome-wide association studies, non-synonymous single-nucleotide variant (NSNV) profiling, and machine learning, we identified strain-specific adaptations in metabolic and regulatory pathways. SSTI isolates exhibited significant enrichment of nitrogen assimilation, purine biosynthesis, menaquinone production, and anaerobic respiration genes. Elevated copy number and colocalization of phage-linked metabolic genes—including nirB, narH, and nifR3—suggest a pathoadaptive genomic island supporting infection-specific energy generation. The enrichment of α/β-hydrolase domain-encoding genes was associated with clinical severity. To quantify severity, we developed the Purulent Ulcer Skin (PUS) score, which integrates wound size, drainage, and erythema. The α/β-hydrolase and lipoprotein genes were significantly associated with higher PUS scores (higher SSTI severity) and phage-encoded virulence gene products were linked to larger wound size. Machine learning prioritized purL and other metabolic loci as key infection classifiers. NSNVs and unitig-level changes co-localized within nutrient transport, stress resistance, and cytolytic genes, supporting a model of multi-layered genomic selection. Metagenomic assemblies of nasal microbiota were enriched for Staphylococcus, Enterococcus, and Micrococcus species, core metabolic pathways, and taxon-specific virulence determinants. This underscores the roles of metabolic and virulent co-networks within nasal commensals and their adaptive capacity for pathogenic transition. These findings provide a potential genomic blueprint of S. aureus pathoadaptation during SSTI and are a step towards the development of novel therapeutic targets. Full article

Background/Objectives: This study aimed to identify the functional adaptations that enable competitive performance in a Paralympic cyclist with optimized bilateral transtibial prostheses compared to a conventional cyclist. Additionally, it describes the development of the prosthesis, designed through a user-centered engineering process incorporating Quality Function Deployment (QFD), Computer-Aided Design (CAD), Finite Element Analysis (FEA), Computational Fluid Dynamics (CFD), and topological optimization, with the final design (Design 1.4) achieving optimal structural integrity, aerodynamic efficiency, and anatomical fit. Methods: Both athletes performed a progressive cycling test with 50-watt increments every three minutes until exhaustion. Cardiorespiratory metrics, lactate thresholds, and joint kinematics were assessed. Results: Although the conventional cyclist demonstrated higher Maximal Oxygen Uptake (VO₂max) and anaerobic threshold, the Paralympic cyclist exceeded 120% of his predicted VO₂max, had a higher Respiratory Exchange Ratio (RER) [1.32 vs. 1.11], and displayed greater joint ranges of motion with lower trunk angular variability. Lactate thresholds were similar between athletes. Conclusions: These findings illustrate, in this specific case, that despite lower aerobic capacity, the Paralympic cyclist achieved comparable performance through efficient biomechanical and physiological adaptations. Integrating advanced prosthetic design with individualized evaluation appears essential to optimizing performance in elite adaptive cycling. Full article