Search Results (1,144)

Background: Morphological characteristics influence physical performance in youth basketball, but their effects may differ by developmental stage. This study compared the predictive role of morphological variables on motor performance between U13 and U15 male players. Methods: Male youth basketball players (N = 89) were assigned to U13 and U15 groups. Morphological variables included height, body mass, body fat percentage, and fat-free mass (FFM). Motor tests evaluated squat jump (SJ), countermovement jump (CMJ), 10 m and 20 m sprints, T-test, Y-test and Stop-and-Go change-of-direction speed and reactive agility (RA). Pearson correlations and multiple linear regressions assessed relationships and predictive effects. Results: In U13 players, several morphological variables correlated with performance: height and FFM were positively related to jumping and sprinting, while body fat was negatively associated with most measures (p < 0.05). Regression models explained substantial variance in sprint (ranging up to _AdjR² = 0.44) and jump performance (ranging up to _AdjR² = 0.32), though individual predictors were not always significant (p > 0.05). In U15 players, fewer associations emerged as body fat remained a significant negative predictor of jumping and agility, and greater body mass was associated with improved sprint performance (p < 0.05). No significant morphological predictors were found for RA in either group (p > 0.05). Conclusions: Morphological traits exert a stronger, multifactorial influence on performance in younger athletes, whereas body composition and particularly body fat are more influential in older adolescents. These results underscore the need to consider the developmental stage when assessing and training male youth basketball players. Full article

Youth soccer performance is influenced by multiple factors, including age, body size, and physical capacities, but the relative contribution of these variables to aerobic and explosive performance remains unclear. Understanding these relationships can improve the interpretation of field tests and support individualized training prescription. This study was designed to examine the association of age category, body mass, and height with physical performance in youth soccer players by jointly considering aerobic and explosive capacities, in order to support the interpretation of field tests within training prescription. Forty-five male players (15 U16, 15 U17, 15 U19) from the same club were assessed across two standardised on-field testing sessions, including the 45–15 test (estimated maximal aerobic speed, MAS) and vertical jump tests (squat jump, SJ; countermovement jump, CMJ; countermovement jump with free arms, CMJ_FH). Performance variables (SJ, CMJ, CMJ_FH, MAS) were treated as outcomes, while category, body mass, and height were included as predictors. A multivariate analysis was performed, followed by univariate analyses for each indicator. Results showed a significant multivariate effect of age category on overall performance (p < 0.001; η²p = 0.482), whereas height and body mass were not significant (p > 0.05). In univariate analyses, age category was associated with all variables: SJ (p = 0.005; adj. R² = 0.160), CMJ (p < 0.001; adj. R² = 0.287), CMJ_FH (p = 0.004; adj. R² = 0.173), and MAS (p < 0.001; adj. R² = 0.352). Performance increased progressively from U16 to U17 to U19, with larger between-category differences in aerobic capacity. In conclusion, age category was more strongly associated with the performance profile than height and body mass when considered jointly; these findings should be interpreted in light of the observational design and the lack of biological maturation measures. Full article

Resistance training (RT) is commonly used to enhance neuromuscular performance and sprint swimming outcomes. However, the optimal relative load for elite junior swimmers remains unclear. In particular, little is known about whether very low relative loads can elicit meaningful adaptations while minimizing neuromuscular fatigue in athletes exposed to high concurrent training demands. Therefore, the aim of this study was to compare the effects of two land-based RT programs differing only in relative load intensity (40–50% vs. 55–65% 1RM), performed with maximal intended concentric velocity, on strength, jumping ability, and 50 m freestyle swimming performance in elite junior swimmers. Eighteen elite junior swimmers (15.6 ± 0.9 years) from a national high-performance program were randomly assigned to a low-load (40–50% 1RM; n = 9) or moderate-load (55–65% 1RM; n = 9) group. Both groups completed an 8-week RT program (2 sessions·week⁻¹) with identical exercise selection, volume, execution velocity, and in-water training load. Neuromuscular performance (countermovement jump, squat, bench press, and pull-up strength) and swimming performance (50 m freestyle from the starting block and in-water start) were assessed pre- and post-intervention. Both RT protocols improved squat and bench press strength and 50 m freestyle performance, whereas significant improvements in countermovement jump, pull-up strength, and maximal pull-up repetitions were observed only in the low-load group. Significant group × time interactions were found for countermovement jump, maximal number of pull-up repetitions, and 50 m freestyle performance from the starting block, indicating more favorable changes over time in the low-load group. In conclusion, both low- and moderate-load high-velocity RT improved neuromuscular and 50 m freestyle performance outcomes in elite junior swimmers. However, the low-load RT (40–50% 1RM) appeared to provide additional benefits in specific outcomes (i.e., jumping, pull-ups, and 50 m performance from the starting block). These findings suggest that relatively low loads may be a practical alternative to moderate-load RT in high-volume swimming training environments. Full article

Patellofemoral pain (PFP) in athletes is associated with lower-limb kinetic-chain constraints, yet rehabilitation strategies targeting both hip and ankle mobility remain insufficiently examined. This assessor-blinded randomized controlled trial investigated the effects of a 6-week hip and ankle mobility-based rehabilitation program in male collegiate athletes with PFP. Forty-eight participants were assigned using computer-generated 1:1 randomization to an intervention group (n = 24) or a control group (n = 24). The intervention group completed supervised hip and ankle mobility rehabilitation three times weekly, whereas the control group maintained regular sport-specific training only. Co-primary outcomes were pain intensity assessed using a 10-cm visual analog scale (VAS) and knee-related function assessed using the Kujala score. Secondary outcomes included hip rotation range of motion, weight-bearing ankle dorsiflexion, vastus medialis–vastus lateralis (VM–VL) onset timing, Y-Balance Test (YBT) composite score, and countermovement jump (CMJ) height. Significant group × time interactions favored the intervention group for VAS (p < 0.0001; partial η² = 0.436; change difference: −1.54 cm; 95% CI: −2.06 to −1.02) and Kujala score (p < 0.0001; partial η² = 0.285; change difference: 8.00 points; 95% CI: 4.24 to 11.76). Significant interactions were also observed for hip internal and external rotation range of motion, weight-bearing ankle dorsiflexion, VM–VL onset timing during a controlled squat task, and YBT composite score (all p ≤ 0.0405; partial η² = 0.088–0.374). No significant group × time interaction was observed for CMJ height (p = 0.0511; partial η² = 0.080). These findings suggest that, compared with regular sport-specific training alone, adding a supervised hip and ankle mobility-based rehabilitation program may improve pain, knee-related function, targeted mobility outcomes, VM–VL onset timing during a controlled squat task, and dynamic balance in the short term. However, because the control group did not receive an active or attention-matched intervention, these findings should be interpreted as the added effect of the supervised rehabilitation program rather than as definitive evidence of mobility-specific treatment effects. In addition, because patellar tracking, knee kinematics, joint kinetics, and patellofemoral joint loading were not directly measured, the findings should be interpreted as clinical and functional outcome changes rather than direct evidence of a confirmed biomechanical mechanism. Trial registration: NCT07542236. Full article

Objectives: Volleyball playing positions are associated with different functional demands. This study compared postural control, jump performance, and upper-limb mobility across playing roles in competitive male volleyball players. Methods: Fifty male volleyball players competing in the Italian Serie C championship were equally distributed across five roles: middle blockers (MB), liberos (LIB), opposite hitters (OH), setters (SET), and outside hitters (HIT). Using a wearable inertial sensor, athletes performed bipodalic balance tasks with eyes open and closed, dominant- and non-dominant-leg single-leg balance, squat jump (SJ), countermovement jump (CMJ), and bilateral upper-limb flexion and extension tests. Results: Significant role-related differences emerged in balance and jump performance. In bipodalic balance, the eyes-open condition showed a mixed pattern, with HIT displaying the largest ellipse area and SET showing the highest path-related values, whereas in the eyes-closed condition, HIT showed the highest values across all stabilometric parameters. In the single-leg stance, OH showed the largest postural excursions on the dominant side, while LIB stood out on the non-dominant side. In jump tests, MB showed the best vertical performance in both SJ and CMJ, whereas LIB and SET generally showed the lowest outputs. Temporal differences also emerged across roles. Upper-limb mobility was similar across roles in flexion, while extension showed a role-specific pattern, with SET displaying greater ROM than LIB, HIT, and OH. Conclusions: Volleyball roles are associated with distinct functional profiles in balance, jump mechanics, and upper-limb mobility. This integrated assessment may support more specific training, monitoring, and injury-prevention strategies. Full article

Research examining the security of network intrusion detection systems is vital for protecting modern digital infrastructure from increasingly sophisticated threats. This study investigates how machine learning network security models, trained with tactical frameworks like MITRE ATT&CK, respond to adversarial examples crafted through black-box optimization techniques. Using three attack algorithms, HopSkipJump, Simultaneous Perturbation Stochastic Approximation Attack and the Square Attack algorithms, we demonstrate that the Random Forest model remains vulnerable despite tactical framework integration. For example, the HopSkipJump attack achieved a 92% success rate in causing malicious traffic to appear benign. Our analysis reveals which network traffic features are most susceptible to manipulation, with model performance metrics declining significantly under adversarial conditions. These findings highlight an important gap between theoretical security frameworks and practical implementation that must be addressed to develop more robust defense systems. By identifying specific vulnerabilities, this research contributes valuable insights that can inform improved adversarial robustness in operational network security environments. Full article

Background: Mixed martial arts (MMA) involve repeated high-intensity, explosive actions that cause substantial fatigue, underscoring the importance of effective recovery strategies. Purpose: This pilot study investigated short-term performance responses to different post-exercise recovery interventions in Polish MMA athletes. Methods: Sixteen athletes (14 males and 2 females) were randomly assigned to cryosauna (CRYO), cold-water immersion (CWI), foam rolling (FR), or passive recovery (CON), with 4 participants per group. The intervention lasted two weeks, with the assigned recovery intervention applied after each training session. Performance was evaluated before and after the intervention using the countermovement jump (CMJ), isokinetic knee peak torque (flexion and extension), and reactive stress tolerance of the determination test (DT). Data were analyzed using mixed-design ANOVA. Results: CMJ performance improved over time across groups. FR significantly increased knee extension (from 228.67 ± 26.49 N.m to 250.50 ± 22.41 N.m), whereas DT scores significantly increased in the CRYO group (from 247.50 ± 12.50 AU to 291.50 ± 15.61 AU) and significantly decreased in the CON group (from 290.25 ± 24.45 AU to 255.50 ± 24.18 AU). Significant Time × Group interactions were observed for DT (p < 0.001) and knee extension torque (p = 0.008). Conclusions: FR appeared beneficial for knee extension performance, whereas CRYO was associated with improved DT performance. Findings are exploratory and need confirmation in larger, controlled studies. Full article

Background: Action observation (AO) and motor imagery (MI) are widely used cognitive training strategies. Recent evidence suggests that their combination may enhance motor simulation through synergistic neural mechanisms. However, the effects of this approach on complex whole-body movements in elite athletes remain unclear. Methods: Twenty-seven elite ski jumpers performed AO, MI, and concurrent AO + MI tasks, while cortical hemodynamic responses were recorded using functional near-infrared spectroscopy (fNIRS). Channel-level changes in oxygenated hemoglobin (ΔHbO) were analyzed using one-sample and paired-sample t-tests, with false discovery rate (FDR) correction applied for multiple comparisons. Additionally, mixed-design ANOVAs were conducted to examine the potential modulation of athlete level (master-level vs. first-class). Results: Significant activation was observed only in the AO + MIcondition after FDR correction, primarily in channels corresponding to the precentral gyrus, postcentral gyrus, and middle frontal gyrus. No channels in the AO and MI conditions survived FDR correction. Between-condition comparisons revealed significant differences in several channels located in frontoparietal regions, including the inferior parietal lobule, supramarginal gyrus, and middle frontal gyrus, with AO + MIgenerally showing stronger responses. No significant effects related to athlete level were found. Conclusions: These findings indicate that concurrent AO + MI is more effective than AO or MI alone in eliciting cortical activation in elite ski jumpers. This may reflect enhanced engagement of frontoparietal networks involved in action representation and visuomotor integration. These results may be compatible with a neural efficiency interpretation in highly trained athletes, although further studies with behavioral outcomes and broader skill-level comparisons are needed. AO + MI may represent a promising strategy for off-snow cognitive training in high-risk sports. Full article

Fencing is an intermittent combat sport in which performance depends on the interaction of neuromuscular qualities, aerobic support, and weapon-specific demands. However, evidence on sex-based differences in the physical capacity profiles of regional fencers remains limited. This study compared the physical capacity profiles of 27 fencers from the Liga Vallecaucana de Esgrima (13 women and 14 men; 14–31 years) in an observational, cross-sectional, comparative study. Field-based assessments included push-ups, sit-ups, squats, jump squats, pull-ups, terminal speed attained in the 20-m shuttle run test, and estimated VO2max. The analysis adopted an exploratory, estimation-oriented approach based on mean differences, 95% confidence intervals, Hedges’ g, supplementary significance testing, false discovery rate adjustment, and a directed acyclic graph to clarify causal assumptions. The most robust sex-based difference was observed in pull-up performance, with men outperforming women by 5.43 repetitions (95% CI: 3.51 to 7.45; g = 1.88), and this was the only comparison retained after FDR correction. No conclusive sex-based differences were found for push-ups, sit-ups, squats, jump squats, terminal shuttle-run speed, or estimated VO2max. Mean estimated VO2max for the overall sample was 43.48 ± 9.12 mL·kg⁻¹·min⁻¹. These findings suggest that upper-limb pulling strength may be the main distinguishing physical quality in this cohort, although its implications for individualized conditioning remain to be established. Nevertheless, the results should be interpreted as observational associations rather than causal effects because of the cross-sectional design, the small sample, the field-based measurements, the imbalance in weapon distribution, and the lack of standardized measures of training exposure. Full article

A biomechanical model of the flight phase in the long jump was constructed to analyze the factors influencing performance. Time-series coordinate data of key joints, obtained through AI-based human pose estimation, were incorporated into the model. For Problem 1, vertical velocity and acceleration of the joints were calculated using the dynamic parameter framework, and reference values with adaptive thresholds were applied to precisely identify take-off and landing moments. For Problem 2, joint information was used to derive arm swing amplitude, take-off angle, and joint rate of change as metrics to characterize athletes’ movement patterns and enable comparison before and after training. For Problem 3, physical and kinematic features were integrated, and Random Forest, multiple linear regression, and Recursive Feature Elimination were employed to evaluate key determinants of long jump performance and provide targeted training recommendations. The first two models achieved R² of 0.9772 and 0.9526, respectively, indicating excellent predictive accuracy. Finally, for Problem 4, the Random Forest and regression models developed in Problem 3 were applied to predict the performance of an athlete following posture optimization training. Full article

Background: Lower-limb performance is commonly assessed using maximal strength, isokinetic, jump, and anaerobic power tests, but whether these assessments provide overlapping or complementary information in healthy young adults without recent regular resistance training remains unclear. Methods: This exploratory cross-sectional secondary analysis examined associations among lower-limb maximal strength, selected isokinetic knee-extension variables, countermovement jump (CMJ) flight time, and 6 s Wingate peak power in 30 healthy male university students. Maximal dynamic strength was assessed using one-repetition maximum (1RM) tests for leg press, leg extension, and leg curl. Isokinetic knee function was evaluated using 60°/s knee extension peak torque and 180°/s knee extension total work. Pearson correlations, body-mass-adjusted partial correlations, and exploratory regression models were performed. Results: Leg press 1RM was strongly correlated with 6 s Wingate peak power, but not with CMJ flight time, in the zero-order analysis. After body-mass adjustment, leg press 1RM was associated with both outcomes. In exploratory regression models, leg press 1RM showed the most consistent associations, whereas the selected isokinetic variables showed less consistent relationships. Conclusions: In this exploratory sample, leg press 1RM showed the most consistent associations with the two performance outcomes examined, particularly 6 s Wingate peak power. The selected isokinetic knee-extension variables appeared to provide more joint-specific information. These findings should be interpreted as sample-specific associations, not as evidence that one test can predict or replace another. Full article

Objective: To examine lower-body stretch–shortening cycle (SSC) indicators across chronological age categories and playing positions in elite male youth soccer players. Methods: In a cross-sectional design, 984 male players from Slovakia (U15–U19) completed Squat Jumps (SJ), Countermovement Jumps (CMJ), and Drop Jumps (DJ) using the OptoJump photocell system. Outcomes included Eccentric Utilization Ratio (EUR), Reactive Strength Index (RSI), DJ Ground Contact Time (DJ GCT), and Jump Heights (JH). Differences were tested using factorial ANCOVA (age category × playing position) adjusted for height and weight, followed by Tukey-adjusted post hoc comparisons (p < 0.05). Results: Significant age-category main effects were observed for DJ RSI, DJ JH, CMJ JH, SJ JH, and DJ GCT. The largest effects were for DJ JH, CMJ JH, and SJ JH (ηp² = 0.096–0.112), whereas the DJ GCT effect was statistically significant but small (ηp² = 0.013). EUR showed no significant differences across age categories (p = 0.586). Positional differences were limited overall and mainly evident in selected U19 outcomes, particularly jump-height variables and DJ GCT. Conclusions: Lower-body SSC performance increased across chronological age categories, with the largest separation in jump-height and reactive strength outcomes. These differences likely reflect a combination of maturation, training exposure, and selection rather than chronological age alone. EUR remained stable across age categories and playing positions, although the JH-based ratio has limited sensitivity in the present test configuration. Positional separation emerged mainly at U19, supporting broad SSC development across earlier youth categories and position-sensitive interpretation in the oldest cohort. Full article

Background/Objectives: Although creatine (Cr) supplementation is well established for enhancing strength exercise adaptations, limited evidence exists regarding whether the timing of a single Cr dose relative to exercise acutely influences performance and related physiological and perceptual responses. This study examined whether the timing of a single dose of Cr ingestion relative to a strength exercise session influences acute strength and power performance, cognitive function, perceptual responses, and selected blood biomarkers in physically active men. Methods: In a randomized, placebo-controlled crossover design, 11 physically active men (26.09 ± 4.39 years) completed five experimental conditions: Cr ingested before exercise (CrB), during exercise (CrD), and after exercise (CrF), placebo (PL), and a no-supplement control. Participants ingested 0.1 g·kg⁻¹ body mass of monohydrate Cr or placebo. Each condition included a standardized strength training session, where bench press (BP) and back squat (BSQ) performance was assessed as the total external load lifted (kg) across six sets performed at 80% of 1-RM for each exercise. Countermovement jump (CMJ) performance, Profile of Mood States (POMS), cognitive performance (digit cancelation test), perceived exertion (RPE), perceived recovery scale (PRS), Delayed-Onset Muscle Soreness (DOMS), and blood markers of muscle damage and renal function were assessed after the resistance training session. Data were analyzed using repeated-measures ANOVA or non-parametric equivalents, with post hoc comparisons adjusted for multiple testing. Results: There was a significant main effect of condition for both BP (F = 4.91, ηp² = 0.33, p = 0.035) and BSQ performance (F = 33.22, ηp² = 0.77, p < 0.001), with greater performance under the CrB condition compared with PL and control (p < 0.05). A significant effect of condition was also observed for creatine kinase (χ² (4) = 12.22, p = 0.016) and creatinine concentrations (χ² (4) = 17.75, p = 0.001). Blood creatine kinase concentrations were greater under CrF conditions than control (p = 0.013) and PL (p = 0.041). Moreover, creatinine concentration was lower under the CrB condition compared to CrD (p = 0.033), CrF (p = 0.003), and the control (p = 0.021). No differences were observed for CMJ performance, cognitive performance, POMS, RPE, PRS, DOMS, or the remaining biochemical markers across treatments. Conclusions: Pre-exercise creatine ingestion (without loading phase) was associated with greater acute strength performance compared with other timing conditions. However, the findings are exploratory and have to be confirmed with a higher sample size and robust placebo/control structures. Full article

The bowling performance of cricket fast bowlers is highly dependent on lower limb power and stiffness. French Contrast Training (FCT) and Velocity-Based Training (VBT) are effective ways to improve rate of force development and peak power. The objective of this study was to investigate the effects of VBT-optimized FCT on the lower limb explosive power and bowling performance of cricket fast bowlers. Twenty adult male medium-fast bowlers volunteered for this study and were evenly divided into an experimental group (EG) and a control group (CG). The EG underwent an 8-week VBT-based FCT program, while the CG completed 8 weeks of traditional resistance training combined with traditional plyometric training. Before and after the intervention, subjects were tested on their Bulgarian split squat load–velocity profile, general lower limb power (countermovement jump height, squat jump height, Eccentric Utilization Ratio, and Reactive Strength Index), and bowling performance metrics (front foot contact time, peak force, impulse, front knee angle at ball release, and ball release speed). The results demonstrated that the EG showing significant advantage over the CG on movement velocity during the Bulgarian split squat at loads 20% 1RM, 40% 1RM, and 60% 1RM (p = 0.008, 0.011, 0.008, ${\eta }_p^2$ = 0.337, 0.313, 0.324). General lower limb power in the EG also improved significantly, with CMJ height, EUR, and RSI showing significant inter-group superiority compared to the CG (p < 0.001, = 0.019, 0.004, ${\eta }_p^2$ = 0.659, 0.281, 0.399). Regarding bowling performance, the EG demonstrated highly significant advantages in front foot contact impulse, front knee angle at ball release, and ball release speed (p < 0.001, ${\eta }_p^2$ = 0.572, 0.590, 0.704). In conclusion, the 8-week VBT-FCT program is more effective than the traditional resistance and plyometric training program of the same duration in enhancing lower limb power and bowling performance for medium-fast cricket bowlers. Full article

Aim: Female athletic performance is shaped by the convergence of menstrual-cycle timing, circadian rhythms, fatigue, and ergogenic supplementation; yet no prior study has examined these factors simultaneously in a sport-specific setting. This study investigated the independent and combined effects of acute caffeine ingestion, calendar-based testing window, time of day, and match-induced fatigue on psychophysiological, cognitive, and physical performance in trained female volleyball players. Methods: Thirteen elite eumenorrheic female volleyball players (age: 24.23 ± 4.06 years) completed a randomized, double-blind, placebo-controlled crossover protocol comprising 12 sessions corresponding to all combinations of testing window (menstrual, follicular, luteal), supplementation (caffeine 6 mg·kg⁻¹ vs. placebo), and time of day (08:00 h vs. 18:00 h). Assessments included the Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index, Spiegel questionnaire, Profile of Mood States, Hooper Index, Stroop task, Countermovement Jump (CMJ), Modified Agility T-Test (MAT), and Reactive Agility Test (RAT), administered before and after a one-hour simulated match. Results: Significant main effects of testing window, caffeine, time of day, and fatigue state were observed across all outcome domains (all p < 0.05). Caffeine reduced daytime sleepiness (F(1,12) = 23.84, p < 0.001, ηp² = 0.665), enhanced vigor (F(1,12) = 114.10, p < 0.001, ηp² = 0.905), and improved MAT performance (F(1,12) = 33.27, p < 0.001, ηp² = 0.735). The follicular window was associated with superior cognitive, neuromuscular, and mood-related outcomes relative to the menstrual and luteal windows. Exploratory higher-order interactions suggested condition-specific caffeine benefits for MAT, RAT, and CMJ, particularly in afternoon post-fatigue conditions; these patterns require replication in larger samples. Conclusions: Acute caffeine ingestion improved several psychophysiological, cognitive, and neuromuscular outcomes in trained female volleyball players, with effects that varied across calendar-based testing windows, time of day, and fatigue state. Individualized supplementation strategies incorporating cycle timing and circadian context remain investigational; prescriptive recommendations require replication in larger, hormonally verified samples before clinical or applied adoption. Full article