Differences in Physical Performance According to Contextual Variables in U21 Football Players
<jats:p>Understanding how contextual variables shape differences in match demands in youth football is essential for optimising performance and player development. Objective: This study aimed to compare physical and competitive performance according to playing position, match location, match result, and opponent quality in the physical and competitive performance of U21 football players from a professional Chilean club. Methods: Twenty male U21 players (19.2 ± 1.2 years) were monitored during 11 official matches using 10 Hz GPS devices (WIMU Pro™) and post-match Rating of Perceived Exertion (RPE). Variables included total distance (TD), high-speed running (HSR > 20 km/h), metres per minute (MM), accelerations/decelerations (N°AC/N°DC > 3 m·s−2), player load (PL), and peak velocity (PV). Contextual variables were classified by playing position, home/away, win/loss, and opponent quality (higher vs. lower rank). Results: Significant between-group differences were found across all contextual factors (p < 0.05). Midfielders (MFs) covered greater TD and reported higher RPE, while full-backs (FBs) and wingers (WGs) reached higher HSR and PV. Away and lost matches showed greater RPE, PL, and N°AC/N°DC, alongside more goals conceded. Facing higher-ranked opponents increased RPE and HSR but reduced explosive actions. Conclusions: Physical performance in U21 football is strongly modulated by contextual factors. Coaches should adjust training load and tactical strategies according to match conditions and positional roles to optimise adaptation and competitive readiness in developmental categories.</jats:p>
Assessment of weekly workload in relation to match workload in U-21 football: Analysis of ten competition microcycles
Football has experienced considerable technological and methodological advancenments, which have also influenced youth football. Currently, youth development faces the challenge of preparing players who can meet the rigorous demands of modern football. Objective: To assess and compare the internal and external training throughout the microcycle (MD-4 to MD-1) with the match-day load in under-21 players from a professional team. Method: Sixteen under-21 footballers from a Chilean professional club (age: 24.9 ± 4.2 years; height: 180.9 ± 6.3 cm; body mass: 78.5 ± 8.5 kg) were monitored over 10 official microcycles corresponding to the Fundación-Collahuasi youth football championship, organized by the Chilean Football Federation. Results: Large differences (p < 0.001 and η²p > 0.2) were found in all variables between the training days and match day. The highest external load occurred on match day, particularly in TD (10,087 ± 708 m), HSR (709 ± 316 m), and PL (130 ± 21.1 au). The highest weekly training loads were recorded on MD-3 and MD-2, while MD-1 showed significant reductions in all variables. Internal load was also highest on match day (RPE: 7.87 ± 1.54) compared to training sessions. Conclusion: There are significant differences in internal and external load throughout the competitive microcycle in under-21 footballers. MD-3 stands out as the highest-load training day, with values comparable to match day in most variables, positioning it as a key session in the weekly plan. In contrast, MD-1 consistently showed the lowest loads, confirming its role as a tapering day before competition.
Skin advanced glycation end-products do not predict pulmonary function trajectories in adults from the ILERVAS cohort
Advanced glycation end-products (AGEs) activate specific receptors (RAGE) promoting inflammation and oxidative stress. The lungs, with high RAGE expression, may be particularly susceptible to AGE-related injury. This study assessed whether baseline skin AGE levels, measured by skin autofluorescence (SAF), predict pulmonary function decline in middle-aged adults with cardiovascular risk factors. This ancillary analysis of the ILERVAS cohort included adults aged 45–70 years with cardiovascular risk factors but without diabetes or chronic kidney disease. Baseline data included demographics, lifestyle, and fasting blood tests. SAF was measured using AGE Reader™, and spirometry performed at baseline and after a median follow-up of 4 years. Associations between baseline SAF and annual declines in FEV1, FVC, and FEV1/FVC were analysed using adjusted models and generalized additive models, stratified by smoking status. Among 658 participants (median age 56 years, 48% female), median baseline SAF was 1.90 AU [1.60; 2.20]. Baseline lung function was preserved, with median FEV1, FVC and FEV1/FVC of 2795 mL [2270; 3,341], 3,525 mL [2870; 4300], and 78.6% [74.4; 82.8]. Annual declines were − 81.9 mL [− 120.6; − 43.3] for FEV1, − 99.6 mL [− 159.3; − 37.9] for FVC, and − 0.04% [− 0.85; 0.70] for FEV1/FVC. No significant associations were found between SAF and spirometry changes. Results were consistent across smoking subgroups. Baseline skin AGE levels did not predict pulmonary function decline over four years in middle-aged adults with cardiovascular risk factors. While SAF reflects cumulative AGE exposure, it has limited prognostic value for lung function in this population.
Prevalence of Motor Competence in Chilean Schoolchildren and Its Association With Sex, Age, and Weight Status: The CoMoSur Study
Background: Chile is one of the countries with the lowest indicators of children’s physical activity therefore it is necessary to promote the development of factors that encourage regular practice, such as motor competence (MC), which is considered a fundamental factor in improving physical activity trajectories in school-age children. This CoMoSur study aimed to determine the prevalence of MC in fifth- and sixth-grade primary school children in central-southern Chile and analyze the association of MC with sex, age, and weight status. Methods: The MC of 1513 schoolchildren (49.4% girls; mean = 11.12 y, SD = 0.92) from 7 regions of central-southern Chile was assessed using the MOBAK 5-6 test. Confirmatory factor analyses and structural equation models were applied to test 2 models: (1) the factorial validity of the 2 dimensions of MC (object control and self-movement) and (2) the associations of MC with sex, age, and weight status. Results: Low levels of MC were observed, especially in girls. Model 1 showed adequate fit indices ( χ 2 = 64.912, df = 19, P ≤ .001, CFI = .975, TLI = .963, RMSEA = .040, SRMR = .035). Model 2 also presented satisfactory fit ( χ 2 = 161.97, df = 37, P ≤ .001, CFI = .943, TLI = .920, RMSEA = .047, SRMR = .071), revealing significant associations: sex is associated with both object control and self-movement, age was positively related to both MC dimensions, and higher weight status was negatively associated with MC. Conclusions: The MC levels in Chilean schoolchildren are concerning, underlining the urgency of implementing intervention programs to strengthen motor competencies. Such strategies should consider differences in sex, age, and weight status to promote sustainable trajectories of physical activity from childhood onward.
Sleep health improvement trajectories after a pandemic: insights from a national health survey
<jats:title>Abstract</jats:title> <jats:sec> <jats:title>Study Objectives</jats:title> <jats:p>This study aimed to evaluate sleep health improvement trends in Catalonia, Spain, from 2020 to 2023 following the COVID-19 pandemic, and to identify disparities across demographic and socioeconomic groups.</jats:p> </jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>This repeated cross-sectional study analyzed 11 794 responses from eight waves of the Catalan Health Survey. Sleep health was assessed using the SATED and Ru-SATED questionnaires, covering six dimensions: Satisfaction, Alertness, Timing, Efficiency, Duration, and Regularity. Trends over time were evaluated, and stratified and interaction models assessed differences by sex, age, BMI, material deprivation, comorbidity burden, and living situation. Survey weights ensured population representativity.</jats:p> </jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>Sleep health improved from mid-2021, then stabilized. Efficiency plateaued by late 2020, while Satisfaction remained the most unstable dimension. Sleep regularity diminished during the 2020 lockdowns but improved promptly afterward. Females consistently scored lower than males, though their improvement trajectories were similar (p-for-interaction = .906). Older adults (65+) and individuals with excess weight exhibited distinctive improvement trends (p-for-interaction = .023). Material deprivation was the strongest predictor of poor sleep health and delayed improvement (p-for-interaction = .024). Living alone had a temporary negative impact during lockdowns, which resolved by 2022. Finally, comorbidity burden affected baseline scores but not improvement trends (p-for-interaction = .467).</jats:p> </jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>Sleep health improvement post-pandemic was uneven across sleep dimensions and population subgroups. Behavioral sleep dimensions improved earlier, while subjective satisfaction lagged. Socioeconomic factors, particularly material deprivation, were strongly associated with poorer and slower improvements. These findings highlight the importance of incorporating sleep health into pandemic preparedness and tailoring interventions to address both behavioral and structural determinants of health.</jats:p> </jats:sec>
Predictive value of physical literacy measures for cardiometabolic risk in adolescents with abdominal obesity: an exploratory study
The objective of this study was to determine the predictive value of different measures of physical literacy (PL) on cardio- metabolic risk in adolescents with abdominal obesity. Method. A cross-sectional, descriptive, and analytical study was con- ducted with a sample of 51 abdominal obesity male adolescents aged 11–15 years. Cardiometabolic risk was estimated using the MetS-score, based on anthropometric, biochemical, and blood pressure data. LASSO regression models were applied to identify the predictive value of PL measures on cardiometabolic risk outcomes. Results. The study findings showed that the physical dimension of PL has measures that moderately predict (f2=0.17), 14.5% of the variance in cardiometabolic risk through the MetS-score. In addition, PL measures were selected to explain other components of cardiometabolic risk, with a large effect on waist circumference and systolic and diastolic blood pressure (f2=3.379; f2=0.771; f2=0.472, respectively). Conclusion. The results of this study show that the physical dimension of PL can predict MetS-scores in abdominal obesity adolescents. Furthermore, it was identified that the psychological and cognitive dimensions of PL, although they do not directly predict the MetS-score, play a relevant protective role in blood pressure and, to a lesser extent, in waist circumference.