Search Results (233)

Background/Objectives: Regular physical exercise is strongly recommended for individuals with type 1 diabetes mellitus (T1DM) because of its beneficial effects on cardiovascular fitness, insulin sensitivity, metabolic control, and overall health. Nevertheless, participation in physical activity remains limited, largely due to the fear of exercise-induced hypoglycemia and glycemic instability. Glycemic responses to exercise in T1DM are influenced by the interaction between exercise modality, circulating insulin levels, nutritional status, and diabetes technologies. Continuous aerobic exercise, resistance training, high-intensity interval exercise, and mixed intermittent activities elicit distinct metabolic and hormonal responses, resulting in heterogeneous glycemic trajectories. This narrative review aimed to provide a clinically oriented synthesis of the physiological mechanisms underlying exercise-related glycemic fluctuations in T1DM and to discuss integrated insulin- and carbohydrate-based strategies to support safer participation in physical activity in the context of modern diabetes technologies. Methods: A structured narrative review was conducted using PubMed/MEDLINE, Scopus, and complementary searches in Google Scholar to identify experimental studies, observational studies, systematic reviews, consensus statements, and clinical guidelines focused on exercise-related glycemic responses in individuals with T1DM. Only articles published in English were considered. Evidence was selected and synthesized according to relevance to exercise modality, insulin therapy strategies, carbohydrate management, and diabetes technologies, including continuous glucose monitoring, continuous subcutaneous insulin infusion, and automated insulin delivery systems. The final narrative synthesis was based on 44 selected studies, reviews, consensus statements, and guidance documents considered most relevant to the objectives of this narrative review. Results: Available evidence indicates that continuous moderate-intensity aerobic exercise is most consistently associated with progressive glucose declines and increased risk of hypoglycemia, particularly when performed in the presence of elevated insulin on board. In contrast, resistance exercise and short-duration high-intensity or anaerobic exercise more frequently induce stable glycemia or transient hyperglycemia through adrenergic stimulation and increased hepatic glucose output. Mixed and intermittent exercise modalities often produce more variable responses depending on exercise sequencing, nutritional status, and insulin exposure. Across studies, integrated adjustment of basal and prandial insulin doses together with individualized carbohydrate supplementation emerged as the most effective strategy to reduce exercise-related glycemic instability. Continuous glucose monitoring and insulin pump technologies improved glucose trend awareness and management flexibility; however, physical exercise remains a challenging condition for current automated insulin delivery algorithms and still requires active user-driven decision-making. Conclusions: Exercise management in T1DM should be based on an individualized interpretation of exercise modality, glucose trends, insulin exposure, and nutritional context rather than on fixed glucose thresholds alone. Combining anticipatory insulin adjustments, tailored carbohydrate strategies, and appropriate use of diabetes technologies may substantially reduce glycemic variability and improve confidence toward physical activity participation. Structured education and individualized clinical guidance remain essential to translate physiological knowledge into effective real-world exercise management. Full article

Background: The aim of this study was to investigate the preliminary evidence supporting the validity of the Running Advisor Billat Training test (RABIT^®) in determining the three intensity domains in male adults with obesity. Methods: Thirteen male adults with obesity completed a graded (GRAD) and a RABIT^® test. The RABIT^® test consisted of three fixed levels of perceived exertion (RPE): (1) 10 min at RPE 13, (2) 5 min at RPE 16, and (3) 3 min at RPE 18. GRAD was composed of 1 min step, increasing speed by 0.5 km/h every minute until volitional exhaustion. Results: At RPE 18, maximal oxygen consumption ($\stackrel{.}{\mathrm{V}}$O₂max), minute ventilation ($\stackrel{.}{\mathrm{V}}$_E), maximal heart rate (HRmax), and running speed were not significantly different from the values measured during the GRAD. As well, oxygen consumption ($\stackrel{.}{\mathrm{V}}$O₂), $\stackrel{.}{\mathrm{V}}$_E, and HR measured during RPE 16 and RPE 13 of the RABIT^® test were not significantly different from the anaerobic threshold (AnT) and aerobic Threshold (AerT) values measured during GRAD. However, running speed at RPE 16 and RPE 13 of the RABIT^® test was lower by −5.03% (p = 0.041) and −7.00% (p < 0.001), compared to GRAD. Conclusions: The data obtained in our study provide preliminary evidence supporting the ability of the RABIT test to estimate maximal exercise parameters, as well as most parameters associated with AerT and AnT. Consequently, the test may be useful for identifying the three training intensity domains and for planning training sessions for adults with obesity. Full article

A newly discovered facultative anaerobic strain, designated as LXY-3^T, was obtained from a soil sample collected at an industrial site in Guangxi, China, known for heavy metal processing. An investigation including phenotypic, chemotaxonomic, and genomic traits was conducted. Phylogenetic analysis based on 16S rRNA showed that LXY-3^T belonged to the genus Paenibacillus. The closest phylogenetic relative of this strain was Paenibacillus anaericanus MH21^T with the similarity of 97.03%. Iso-C_15:0, antéiso-C_15:0, and C_16:1 ω7c alcohol were the major cellular fatty acids. The predominant polar lipids comprised diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), unidentified phospholipids (PL1-PL8), unidentified resistant material (RM1–RM4), and lipids (L1–L3). For genome sequencing, the genomic DNA G+C content of the strain is 51.2 mol%. Comparative genomic analysis revealed that the average nucleotide identity (ANI) values between strain LXY-3^T and its closest phylogenetic relatives within the genus Paenibacillus (represented by type strains) were consistently below the 95% species demarcation threshold. Nitrogen fixation gene cluster (nifB, nifE, nifK, nifN, nifV, nifX, nifD, and nifH) was conserved in the strain. Correspondingly, digital DNA–DNA hybridization (dDDH) values remained below the 70% cutoff for species delineation. These genomic metrics provide compelling evidence that strain LXY-3^T represents a novel species within the genus Paenibacillus. The type strain LXY-3^T (=CGMCC 1.64949^T = JCM 37600^T) is proposed. Full article

Basketball performance is influenced by cardiorespiratory fitness and body composition. However, evidence regarding the ability of maximal oxygen uptake (VO₂max) to distinguish between competitive levels remains inconsistent. This study aimed to examine differences in cardiorespiratory fitness and body composition between professional and amateur basketball players and to explore their contribution to variability in relative VO₂max. This pilot study also informed sample size estimation for future studies. A cross-sectional study was conducted with 12 professional (21.0 ± 2.3 years; BMI: 25.37 ± 3.04 kg/m²) and 12 amateur (22.6 ± 1.7 years; BMI: 26.83 ± 3.24 kg/m²) male basketball players. Absolute and relative VO₂max, ventilatory thresholds, and body composition (five-component fractionation) were assessed. Between-group comparisons were performed using Welch’s t-tests, effect sizes were estimated using Hedges’ g, and covariance analyses were adjusted for height and body fat percentage. No statistically significant differences were observed in relative VO₂max between groups. However, the absolute second ventilatory threshold was significantly higher in professional players, and absolute VO₂max showed a large effect size favoring this group. Professionals also showed lower body fat percentage and greater fat-free mass (p < 0.01; g ≈ 1.2). These findings suggest that body composition differences may partly explain variability in relative VO₂max between competitive levels. Full article

In heart failure (HF), elevated blood lactate levels, particularly during exercise or in advanced disease stages, reflect impaired tissue perfusion and altered metabolic regulation. Beyond its traditional role as a marker of anaerobic metabolism, lactate has emerged as a dynamic indicator of metabolic reserve and ventilatory control. This narrative review summarizes current evidence on lactate dynamics at rest and during exercise, highlighting their pathophysiological and clinical relevance. In HF patients, exercise-induced lactate accumulation occurs earlier and at lower workloads, reflecting impaired oxidative capacity and reduced peripheral oxygen utilization. This phenomenon is closely associated with ventilatory inefficiency, as demonstrated by the relationship between lactate levels and the VE/VCO₂ slope during cardiopulmonary exercise testing (CPET). Emerging data suggest that lactate is not only a marker of disease severity but also a potential mediator of chemoreflex activation and abnormal ventilatory responses. Furthermore, both pharmacologic and non-pharmacologic interventions may influence lactate production and utilization, supporting its role as a potential tool for therapeutic monitoring. Overall, the integration of lactate assessment, particularly during exercise, into clinical evaluation may provide additional insight into disease mechanisms, improve risk stratification, and contribute to personalized therapeutic optimization in patients with HF. Full article

This study aimed to identify distinct lactate kinetic phenotypes in professional soccer players using unsupervised machine learning and determine their relationship with maximal running velocity (V_max) through explainable artificial intelligence methods. A total of 361 professional male soccer players from the First Division participated in the study. Incremental treadmill tests measured lactate concentrations at five standardized velocities, alongside VO_2max, V_max, lactate threshold (LT), and anaerobic threshold (AT) parameters. Three distinct lactate kinetic phenotypes emerged: Economical Aerobic (n = 216), Balanced Metabolic (n = 19), and High Producer (n = 126). The Economical Aerobic phenotype demonstrated superior performance metrics compared to High Producer (V_max: 15.85 ± 0.85 km/h; VO_2max: 56.20 ± 4.26 mL/kg/min; p < 0.001). Initial multicollinearity assessment revealed notable collinearity among all 10 candidate predictors (VIF > 10; maximum VIF = 10.75 for V_AT), necessitating rigorous feature selection. Ridge regression with 4 selected features (V_AT, VO_2max, 9.5 km/h lactate, 14 km/h lactate) achieved moderate but statistically significant predictive performance: 10-fold cross-validation R²= 0.392 ± 0.147 (permutation test p = 0.001). Standardized coefficients identified V_AT (β = 0.399) as the dominant predictor, followed by VO_2max (β = 0.253), 9.5 km/h lactate (β = 0.107), and 14 km/h lactate (β = −0.066). Lactate kinetic phenotyping reveals position-independent metabolic profiles with potentially meaningful performance associations in professional soccer. The Economical Aerobic phenotype demonstrates performance advantages associated with superior anaerobic threshold capacity. These exploratory findings suggest that individualized training strategies based on metabolic phenotype rather than playing position alone warrant further investigation, with potential applications for talent identification, training periodization, and return-to-play protocols pending prospective validation. Full article

Background: Ice hockey is characterized by repeated short-duration, high-intensity efforts interspersed with brief recovery periods, requiring a complex interaction of aerobic and anaerobic energy systems. The aim of this study was to determine the energetic structure of repeated high-intensity on-ice sprint exercise in ice hockey players by quantifying the relative contributions of the oxidative, glycolytic and ATP–PCr energy systems. Methods: 14 male semi-professional ice hockey players performed the 30–15_IIT followed by the Repeated High-Intensity Effort (RHIE) on-ice. Oxygen uptake was measured breath-by-breath, blood lactate concentration and energy system contributions were estimated using a three-component PCr–La–O₂ model. Results: The RHIE on-ice was characterized by a dominant aerobic contribution (63.1 ± 2.6%), followed by phosphagen metabolism (29.8 ± 2.9%), with a relatively small glycolytic contribution (7.4 ± 1.5%). Conclusions: No significant relationships were observed between maximal oxygen uptake (VO_2max) and the RHIE performance parameters, energy system contributions or lactate responses, except for a moderate relationship between absolute VO_2max and absolute aerobic work. In contrast, parameters determined at the anaerobic threshold showed more consistent relationships with absolute metabolic work. These findings indicate that repeated high-intensity on-ice performance in ice hockey is largely independent of VO_2max and is more closely related to individual energetic profiles and metabolic tolerance. Full article

Slaughterhouse by-products are promising feedstocks for anaerobic digestion due to their high lipid and protein content. However, their complex structures often limit hydrolysis, and excessive pretreatment can induce inhibitory conditions. This study evaluates the effects of ball-milling (BM), ball-milling with water (BM + water), and combined thermal hydrolysis and ball-milling (THP + BM) on the digestion performance of a mixed substrate of slaughterhouse and agricultural wastes. The results demonstrate that all BM-based pretreatments significantly improved digestion kinetics, reducing the lag phase by 26–66% and shortening the T₅₀ values by approximately 40% compared to the untreated substrate. While no statistically significant differences were observed in the ultimate methane yield, the onset of methanogenesis was markedly accelerated in the BM and BM + water treatments. In contrast, despite achieving superior solubilization, the THP + BM treatment failed to provide proportional kinetic enhancements. This was attributed to a severe initial metabolic imbalance—characterized by a pH drop below the inhibitory threshold (6.33)—which induced physiological stress and delayed the functional recovery of methanogens. These findings indicate that while ball-milling effectively facilitates digestion initiation by enhancing physical accessibility, the intensity of combined thermal-mechanical processes must be strategically optimized. For high-strength organic biomass, managing pretreatment severity is crucial to prevent initial acid stress and maximize process efficiency. Full article

Background: Succinic acid plays a central role in human energy metabolism as a key intermediate of the Krebs cycle that releases energy accumulated as guanosine triphosphate (GTP). Through its conversion via succinate dehydrogenase (SDH), succinate directly links the Krebs cycle to oxidative phosphorylation (OXPHOS), contributing to adenosine triphosphate (ATP) production. Exercise induces pronounced changes in succinate concentrations in skeletal muscle, blood, and saliva, with responses influenced by training status, exercise modality, and intensity. Objective: This systematic review evaluated the effects of succinate-containing supplements or sole-ingredient succinic acid supplementation on exercise performance and post-exercise recovery in healthy trained individuals. Methods: The review was conducted in accordance with PRISMA guidelines. PubMed/MEDLINE, Scopus, Web of Science, and Google Scholar were searched without date restrictions. Interventional studies assessing succinate-containing supplementation with outcomes related to exercise performance or recovery were included. Methodological quality was evaluated using the Cochrane Risk of Bias 2 tool. This study was registered in advance with the International Prospective Register of Systematic Reviews (PROSPERO, CRD420251237042). Results: Six studies involving 153 participants (mean age: 23 years) met the inclusion criteria. Five of the six included studies were rated as having a high risk of bias, while the only study judged to be at low risk of bias reported no beneficial effects on exercise performance outcomes. Supplementation protocols included daily doses of 300–2040 mg for up to 21 days and a single acute dose of 30 mg/kg, with most interventions administering succinate as part of multi-ingredient formulations rather than as an isolated compound. Three studies reported ergogenic effects in direct performance metrics, including improvements in maximal oxygen uptake, oxygen consumption, anaerobic threshold power, and total work performed. Two additional studies demonstrated favorable physiological adaptations indirectly relevant to exercise performance, including improved acid-base regulation, hematological markers related to oxygen transport, and antioxidant status, although validated performance outcomes were not assessed. Substantial heterogeneity and overall methodological limitations precluded meta-analysis. Conclusions: Current evidence suggests that succinate-containing supplements or sole-ingredient succinic acid supplementation may enhance direct performance outcomes such as aerobic performance, total workload, and indirect physiological markers, e.g., acid-base balance, hematological indicators and antioxidant capacity in healthy trained individuals. However, given that the majority of included studies were at high risk of bias and the only low-risk study reported no ergogenic effects, current evidence does not provide reliable support for performance-enhancing benefits of succinate supplementation. Interpretation is further limited by the predominant use of multi-ingredient formulations, making it difficult to isolate the effects of succinic acid. While biologically plausible mechanisms exist, well-controlled trials using isolated succinic acid are required before conclusions regarding efficacy can be drawn. Full article

Background/Objectives: This study examined the acute effects of different doses of melatonin on performance, physiological, and psychophysiological responses during individualized exhaustive cycling exercise. Methods: Fifteen physically active but cycling-inexperienced men (18–35 years) completed a double-blind, randomized, placebo-controlled, crossover protocol. Following an incremental test to determine the anaerobic threshold (AnT), participants performed four exhaustive exercise sessions at 80% of AnT after ingesting placebo or melatonin (5, 12.5, or 20 mg), administered approximately 30 min before exercise. Time to exhaustion (TLim) was considered the primary performance outcome. Heart rate, peripheral oxygen saturation, blood lactate concentration, blood glucose, and ratings of perceived exertion were assessed before, during, and after exercise. Results: No significant differences were observed between experimental conditions for TLim or for any physiological or psychophysiological variable. Only main effects of time were detected, reflecting expected exercise-induced responses, with small effect sizes and no evidence of a dose–response relationship across melatonin conditions. Baseline values were comparable among sessions. These findings indicate that acute melatonin administration at doses ranging from 5 to 20 mg does not elicit ergogenic effects nor modulate physiological or psychophysiological responses during prolonged individualized cycling exercise in healthy individuals. Conclusions: In male, healthy, physically active individuals inexperienced in cycling, acute melatonin administration at the doses tested did not produce ergogenic effects or alter physiological and psychophysiological responses during prolonged, individualized cycling exercise. Full article

The annual soccer training cycle consists of preparatory, competitive, and transition periods. The transition phase is usually characterized by a decrease in training volume, which may lead to detraining and declines in physical fitness. The aim of this study was to examine the effects of a structured transitional training program on anthropometric characteristics, aerobic capacity, and jumping performance in young soccer players. Twenty-three under-17 players participated in the study and, following a two-week period of training cessation, completed a three-week program that included aerobic training three times per week (continuous and interval running sessions) and strength progressive resistance training twice per week. Pre- and post-intervention measurements were analyzed using paired-samples t-tests, with statistical significance set at p < 0.05. The results revealed significant reductions in body fat percentage (p = 0.016, d = 0.547), body fat mass (p = 0.018, d = 0.535), and resting systolic blood pressure (p = 0.024, d = 0.507). Additionally, time to reach the anaerobic threshold (p = 0.022, d = −0.515) and movement speed at the anaerobic threshold (p = 0.029, d = −0.487) significantly increased. No significant changes were observed in the remaining variables. These findings indicate that a three-week transition-period training program combining structured aerobic running drills with progressive resistance training can induce favorable adaptations in selected anthropometric and physiological parameters in youth soccer players. However, the lack of a control group should be considered when interpreting the magnitude of the program’s effects. Full article

Background: Foam rolling is a popular self-myofascial release (SMR) technique, yet empirical evidence regarding its long-term impact on cycling endurance remains inconclusive. This study investigated the effects of chronic SMR on cardiorespiratory capacity, metabolic kinetics, and mechanical performance in road cyclists. Methods: We conducted a six-month randomized controlled trial (RCT) with 32 male recreational cyclists. Both an intervention group (IG) and a control group (CG) followed a standardized training protocol. The IG additionally applied a Blackroll^® foam roller immediately after cycling training sessions. Outcomes included maximum oxygen uptake (VO₂max), submaximal heart rate, lactate slope, and relative mechanical power (W/kg) at aerobic and anaerobic thresholds. Data were analyzed using linear mixed-effects models (LMM), with age included as a fixed-effect covariate to control for baseline imbalances between groups. Effect sizes were determined via marginal and conditional R². Additionally, model robustness was verified through Shapiro–Wilk tests and Q–Q plots of conditional residuals. Results: No significant effects were observed for VO₂max or submaximal heart rate. In contrast the IG demonstrated significant improvements in metabolic kinetics, evidenced by a reduced lactate slope (p = 0.004). Furthermore, foam rolling yielded a statistically significant positive effect on relative mechanical performance at both the aerobic (p = 0.031) and anaerobic (p = 0.007) lactate thresholds. Sensitivity analyses confirmed that these effects were independent of the age difference between groups. Conclusions: Foam rolling did not enhance all endurance-related variables but showed positive effects on metabolic kinetics and mechanical performance. While it did not shift systemic cardiorespiratory limits, SMR appeared to optimize performance through improved metabolic economy and mechanical efficiency, suggesting it is a valuable supplemental tool for recovery and long-term performance maintenance in cycling. Full article

The AP2/ERF superfamily is a key class of transcription factors involved in plant responses to various stresses. As an ancient species, the olive tree (Olea europaea L.) exhibits considerable stress tolerance and wide adaptability. In this study, we identified 348 AP2/ERF genes in the cultivated olive variety ‘Arbequina’ at the whole-genome level. According to protein sequence alignments and phylogenetic analyses via the Maximum Likelihood method, these genes were classified into four major families: AP2, ERF/DREB, RAV, and Soloist. The ERF/DREB family was further divided into DREB and ERF subfamilies, each encompassing six groups (A1–A6 and B1–B6), with the ERF subfamily being the largest. Members of each group exhibited relatively consistent gene structures and domain/motif compositions of their encoded proteins; however, the distribution of cis-elements and expression patterns varied. Each AP2/ERF gene contained 12 light-responsive, three MeJA-responsive, three ABA-responsive, two anaerobic induction, and one MYB binding site on average. With the threshold of p value < 0.5, control TPM > 0, and |log₂(fold change)| > 0, 50 candidate genes were simultaneously up-regulated (30) or down-regulated (20) under four stress treatments (acid–aluminum, cold, disease, and wound), among which nine showed potential protein–protein interactions. This study provides a comprehensive genomic characterization of the AP2/ERF family in olive and identifies key candidate stress-responsive genes, establishing a foundation for future functional studies on the molecular mechanisms of stress adaptation in the olive tree. Full article

The aim of the study was to determine the effects of sprint interval training (SIT) on anaerobic and aerobic performance in young physically active men, as assessed by maximal power (Pmax), maximal oxygen uptake (VO₂max), and the second ventilatory threshold (VT2). The data obtained were presented against the background of the effects of aerobic interval training. Participants (n = 45) aged 19–27 years were recruited into three groups of 15 participants each. The first group performed SIT, the second performed aerobic interval training (AIT), and the third group was without any intervention (control—CON). In each study group, participants performed somatic measurements twice (before and after the exercise intervention), the Wingate test (assessing peak anaerobic power (PP)), and a graded exercise test assessing aerobic performance. The training intervention in the SIT and AIT groups lasted 6 weeks, with three training sessions per week. The duration of a single session in AIT was constant throughout the intervention and lasted 60 min, while in SIT it lasted 17 min (first session), and the longest training session lasted 30 min. Training in the SIT group resulted in a significant increase in absolute anaerobic peak power (p < 0.001, ES = 0.36), while no significant change in PP was observed after AIT (p = 0.13, ES = 0.24). Both training protocols (SIT and AIT) significantly improved VO₂max (p = 0.03, ES = 0.39 and p = 0.02, ES = 0.55, respectively) and absolute Pmax (p < 0.001, ES = 0.68 and p = 0.02, ES = 0.36). Only in the AIT group were statistically significant changes related to VT2 observed: after training, oxygen uptake at VT2 increased significantly (p = 0.04, ES = 0.64). The SIT protocol improved both aerobic (VO₂max) and anaerobic (PP) performance, but did not affect the VT2 level. The data indicate that SIT can be used for training in sports disciplines requiring aerobic and anaerobic performance. Full article

Firefighting requires high and multidimensional fitness to ensure operational readiness and public safety. In Portugal, there is limited data regarding firefighters’ fitness and exercise programs to improve readiness are lacking. This study evaluated the effects of a 6-month minimal-equipment exercise program on the physical fitness of firefighter recruits. Thirty-five male subjects (23.0 ± 2.72 years) were assessed at baseline,3 and 6 months for body composition, handgrip strength, running speed, cardiovascular endurance, anaerobic power, and upper- and lower-body strength. The intervention entailed daily sessions with 15 min of continuous running (50–65% HRmax) and active stretching, followed by alternating routines, including endurance running, free weights, interval sprints, calisthenics, and drills. A repeated-measures ANOVA and Bonferroni adjusted post hoc comparisons identified time-based changes. Significant improvements occurred across all fitness variables. Body fat fell by 8.4% and VO₂max increased (p < 0.001), surpassing occupational thresholds required for extended suppression tasks. Bench press and sit-up performance improved by 88% and 81%, respectively, while countermovement jump showed double-digit gains (13%), all of which can translate directly to hose advancement, victim rescue, and forcible entry. These results highlight that resource-constrained departments can implement effective, low-cost exercise programs for enhancing pivotal fitness components, supporting policy initiatives to include structured training throughout firefighters’ careers. Full article