PURPOSE:To determine the association between meeting 24-hour movement guidelines and markers of adiposity in children, including body mass index, waist circumference, waist-to-height ratio, and percentage body fat. METHODS:The sample included 910 children aged 6-10 years from Northern Portugal. Meeting the 24-hour movement guidelines was defined as (1) moderate-to-vigorous physical activity (MVPA): ≥60 minutes per day, (2) sleep: 9 to 11 hours/night, and (3) screen time: ≤2 hours per day. Moderate-to-vigorous physical activity and sleep duration were assessed with wrist-worn accelerometry over 7 days, and screen time was assessed by parental report. RESULTS:A total of 5.4% of the sample met none of the guidelines, whereas 23% met all 3 guidelines. Children who met individual guidelines (MVPA, screen time, and sleep) had significantly lower levels of body mass index z-scores and waist circumference, whereas those who met the MVPA and sleep guidelines had lower waist-to-height ratio. Those who met the MVPA guideline had lower percentage body fat than those who did not. There were significant linear trends (all P < .01) between the number of guidelines met (0, 1, 2, and 3) and lower levels of all markers of adiposity. CONCLUSIONS:We found significant associations between meeting 24-hour guidelines and lower levels of adiposity among Portuguese children.
PURPOSE:Dysfunctional breathing contributes to exercise intolerance (EI) but is difficult to diagnose. We developed a novel approach to evaluate the ventilatory response during cardiopulmonary exercise tests (CPET), measuring the average change in respiratory rate (RR) relative to the change in tidal volume (Vt). We hypothesized that this RR:Vt slope ratio will uncover unique ventilatory responses among different groups of patients experiencing EI. METHODS:An exploratory retrospective review was conducted on CPET for patients with EI from January 2017 to July 2024. Demographics, spirometry, CPET, and auscultatory findings of stridor during exercise were compared among patients with an elevated RR:Vt to patients with a lower RR:Vt ratio with and without stridor. RESULTS:CPET from 65 patients, mean age 14.8 (9-20) years, were compared among those with an elevated RR:Vt ratio (21 patients, ratio 43.0) and patients with a lower RR:Vt ratio with stridor (19 patients, ratio 22.6) and without stridor (25 patients, ratio 22.1). Patients with an elevated RR:Vt were younger with reduced Vt and minute ventilation expansion at peak exercise with no differences in peak oxygen uptake. CONCLUSION:Groups of patients with EI exhibit a higher RR:Vt ratio, reflecting an altered breathing pattern that may be consistent with dysfunctional breathing.
PURPOSE:The present study compared cross-sectional (CS) and longitudinal (LT) data for changes in anthropometric and performance parameters in junior speed skaters to examine how well the CS data reflects individual LT changes. METHODS:The CS data consisted of 404 Japanese male skaters of 11 (n = 60), 12 (n = 67), 13 (n = 73), 14 (n = 69), 15 (n = 53), 16 (n = 40), and 17 years (n = 42) taken between 2004 and 2019. The LT data followed 11 other male skaters whose 6 consecutive year (11-17 y) data were available. Outcome measures included height, body mass, body mass index, lower limb circumferences, muscle thicknesses, maximal anaerobic power during 10-second maximal bicycle pedaling, peak speed in slide bord skating, and average ice-skating speed in 500 m. RESULTS:The average values of the measures were not different (P = .795-.999) between the CS and LT data at any age (eg, body mass index: 21.7 [2.0] vs 22.3 [2.3] kg/m2; anterior thigh muscle thicknesses: 60.5 [5.1] vs 60.5 [4.5] mm; maximal anaerobic power: 1022 [141] vs 1026 [164] W; average ice-skating speed in 500 m: 12.5 [0.4] vs 12.5 [0.4] m/s at 17 y). Changes in the measures from 11 to 17 years were not different (P = .750-.998) between the CS and LT data. CONCLUSION:These findings suggest that the CS data approximate individual developmental trends, when cohort bias is adequately controlled, but cannot substitute for LT analyses.
PURPOSE:Investigate the associations of cumulative exposure to physical activity (PA), sedentary time (ST), and screen time from childhood to adolescence over an 8-year follow-up with cognition in adolescence. METHODS:All together, 260 adolescents (136 boys) who were 15-17 y at 8-y follow-up were analyzed. PA and ST were assessed using an Actiheart device, and different types of PA, nonscreen-based ST, and screen time were assessed by a questionnaire at baseline, 2-y and 8-y examinations. Cognition was assessed using CogState tests at 8-year examinations. RESULTS:Self-reported cumulative unsupervised PA from childhood to adolescence was inversely associated with accuracy in working memory task (standardized regression coefficient, β = -0.127; 95% confidence interval [CI], -0.247 to -0.008) in adolescence. Self-reported nonscreen-based ST was inversely associated with reaction time (β = -0.176; 95% CI, -0.299 to -0.053) and accuracy (β = -0.149; 95% CI, -0.274 to -0.024) in working memory tasks. Self-reported screen time was inversely associated with reaction time (β = -0.194; 95% CI, -0.316 to -0.071) and accuracy (β = -0.233; 95% CI, -0.355 to -0.112) in both working memory tasks and directly associated with overall cognition (β = 0.187; 95% CI, 0.070 to 0.305). CONCLUSION:Accumulating less unsupervised PA and more screen time from childhood to adolescence was associated with better cognition in adolescence.
PURPOSES:In pediatric cardiology, stress echocardiography is rarely used, even though it is an established tool for investigating myocardial dysfunction due to coronary insufficiency, a threat in children after arterial switch operation (ASO) or Kawasaki disease (KD). This study combines stress echocardiography with cardiopulmonary exercise testing in this cohort. METHOD:The participants in this study were recruited from a cohort of patients after ASO or KD. An age- and sex-matched control group was recruited from university students and school children from nearby schools. All undertook a cardiopulmonary exercise testing either on a tilt-recline cycle ergometer or on a treadmill with intermittent echocardiography. The echocardiographic examination consisted of global longitudinal strain measurements of the left ventricle as parameters of left ventricular function. In addition to the standard cardiopulmonary exercise parameters (peak oxygen consumption, peak heart rate, O2pulse, oxygen uptake efficiency slope, V˙E/V˙CO2-slope, and others), the behavior of the O2pulse before and after the end of exercise was evaluated. RESULTS:Overall, 43 participants were recruited (20 ASO, mean age: 14.7 y, 8 females; 10 KD, mean age: 15.0 y, 3 females; 13 controls, mean age: 15.7 y, 5 females). The patients after ASO showed a significantly lower peak cardiopulmonary function (V˙O2peak: 39.6 vs 45.9 mL/kg/min) than the control group. When combined (KD and ASO patients), the first ventilatory threshold as well as the decline of the O2pulse during recovery were significantly lower than in the control group. There were no differences with respect to the echocardiographic parameters. CONCLUSION:The lower peak oxygen consumption observed in the ASO group point to a lower cardiopulmonary function. The lower oxygen consumption at first ventilatory threshold can be an indicator of poorer endurance. Even though the ventricular function recorded using echocardiography showed no significant decrease, the slower recovery of the O2pulse during recovery could point to an impairment in cardiac output during exercise as the O2pulse is a surrogate parameter of cardiac output at peak exercise.
PURPOSE:Glycemic variability is a potential risk factor for cardiometabolic disease. As adolescence is a critical period for establishing metabolic health, this study examined associations between daily physical activity (PA) levels, sedentary time, and glycemic variability in healthy adolescents under free-living conditions. METHODS:Eighty-seven adolescents (53 girls; mean age: 12.9 [0.8] y) wore a continuous glucose monitor (FreeStyle Libre) and an accelerometer (ActiGraph) concurrently over 8 days. Generalized estimating equations examined daily associations in participants with ≥3 days of concurrent accelerometer/continuous glucose monitor data, after adjusting for key confounders. RESULTS:Vigorous PA was consistently associated with a lower glucose coefficient of variation (exponentiated beta coefficient [exp β] = 0.898; 95% CI, 0.828-0.974; P = .010), mean amplitude of glycemic excursion (exp β = 0.889; 95% CI, 0.804-0.983; P = .022), and SD of glucose (exp β = 0.914; 95% CI, 0.845-0.988; P = .023) and a greater percentage in the 3.9 to 7.8 mmol·L-1 glucose range (exp β = 1.020; 95% CI, 1.003-1.038; P = .019). Moderate-to-vigorous PA was also inversely associated with coefficient of variation and SD of glucose (P ≤ .018). Yet, sedentary time, light PA, moderate PA, and total PA were not significantly associated with any glycemic metric (P ≥ .145). CONCLUSION:PA at moderate-to-vigorous, and especially vigorous, intensities was associated with lower glycemic variability in healthy adolescents.
Purpose: To compare the sleep behavior, cortisol, and immunoglobulin A responses between 2 conditions; an experimental condition consisting of 2 consecutive weeks of school and training commitments with low- and high-load training and a 3-day control condition without school and training obligations. Methods: Objective sleep characteristics were monitored using ActiGraphy in 11 female water polo athletes (age: 12.9 [1.2] y) during both conditions. In the experimental condition, a low-load training week was followed by a high-load training week. Salivary cortisol and immunoglobulin-A were measured before training. Results: Sleep duration was lower and awakenings were fewer in experimental condition compared to control condition (duration: 464.1 [20.6] vs 501.3 [85.0] min, P = .02, d = 0.66; awakenings: 17.4 [8.4] vs 21.1 [10.2], P = .02, d = 0.71). Sleep characteristics were similar between training conditions; however, variability in time in bed and total sleep time was lower during high- (12.34% [6.46%] and 13.32% [7.59%]) than low-load training (16.30% [7.43%] and 17.32% [5.50%]) (P<.01, d = 1.12 and P = .04, d = 0.70). Salivary cortisol and immunoglobulin-A levels were higher during high-load than low-load training (P< .01, d = 1.02 and P< .01, d = 1.38). Conclusions: School and sports training commitments reduce sleep duration but improve sleep quality in adolescent water polo athletes, while high-load training reduces sleep variability and increases allostatic load without altering sleep characteristics.
PURPOSE:This study examined the effect of dual-task (DT) training on motor, cognitive, and DT performance in school-aged children. METHODS:The study sample consisted of 108 children, aged 8-10 years, living in a province in eastern Türkiye, between April and December 2024. Participants completed the 10-m walk test, the 2-minute walk test, and the timed sit-to-stand test under both single-task conditions and DT conditions, which involved performing a concurrent cognitive task. The study group received DT training during physical education classes once a week for 40 minutes over a 4-week period, while the control group continued their regular physical education classes. RESULTS:Significant improvements were observed in the study group between the first and last measurements for both single-task cognitive (t = -4.035; P = .000) and single-task motor (t = -3.182; P = .002) performance. There were no differences in the difficulty levels of the cognitive and motor tasks between the study and control groups (P > .05). However, significant differences were found between the groups in adjusted posttest scores for the DT condition (F = 9.010, P = .003, η2 = .079). CONCLUSIONS:DT training enhanced cognitive, motor, and DT performance in school-aged children. The findings suggest that pediatrics professionals should consider incorporating DT training more widely in practice.
PURPOSE:Understand how pubertal progression is associated with physical activity behaviors in adolescent girls. METHODS:Longitudinal analysis of early adolescent girls (n = 2778, aged 11.9 y) from the Adolescent Brain Cognitive Development study was conducted. Pubertal trajectories were characterized via latent class analysis. Physical activity measures were derived from Fitbit accelerometers at year 2. Multivariate linear regression analyses examined how pubertal progression predicted physical activity patterns. RESULTS:Girls with early puberty showed fewer steps (b = -506, P < .001), and girls with slow pubertal progression had more steps (b = 580, P < .001), compared with those with typical puberty. Girls with early puberty had more sedentary time (b = 17.9, P < .001), and girls who had slow pubertal progression had less sedentary time (b = -18.3, P < .001), compared with girls with typical puberty. CONCLUSIONS:Girls who developed puberty early had fewer steps and more time spent in sedentary behaviors. A gradient was observed for both steps and sedentary time, with slow progressors engaging in the most steps and least sedentary time, followed by typical progressors, with early progressors showing the fewest number of steps and longer time spent in sedentary behaviors. Girls who progress through puberty early might benefit from additional resources to stay engaged in PA opportunities.
Despite the well-documented role of swimming competence in preventing childhood drowning, little is known about how preschoolers' swimming competence differs across cultural contexts. This study aimed to examine cross-regional variations in swimming competence and related behavioral and environmental factors among preschoolers. Parent-child dyads (N = 2059) from the United States (n = 500), Australia (n = 500), Singapore (n = 507), and Hong Kong (n = 552), with children aged 2-6 years (Mage = 4.23 [1.10] y), completed the Swimming Competence Questionnaire. Preschoolers had an average maximum swimming distance (max-dis) of 17.80 (61.12) m, and a swimming competence index (SCI) of 15.50 (19.56) out of 100. Preschoolers from Australia (Mmax-dis = 13.46 [12.24] m; MSCI = 19.59 [20.46]) and the United States (Mmax-dis = 13.91 [11.98] m; MSCI = 16.35 [18.77]) had significantly better swimming competence than those from Singapore (Mmax-dis = 26.46 [50.19] m; MSCI = 14.77 [18.44]) and Hong Kong (Mmax-dis = 18.96 [21.05] m; MSCI = 12.80 [20.35]). Compared with those from other regions, preschoolers from Australia had the highest swimming frequency and greatest accessibility to swimming facilities, and they were more likely to receive professional swimming instruction. Findings underscore the importance of providing children with opportunities to engage in swimming to improve swimming competence.
BACKGROUND:Fundamental motor skills (FMS) support children's participation in health-enhancing physical activity (PA), yet it remains unclear whether postintervention motor skill gains translate into increased PA. PURPOSE:This study used cross-sectional and prospective analyses to examine associations between changes in preschoolers' FMS and PA immediately following the Children's Health Activity Motor Program and again 6 months later. METHODS:Preschoolers (N = 153; 86 girls, mean age = 53.14 mo [4.43 y]) from 3 preschool centers participated. Process-oriented FMS were assessed using the Test of Gross Motor Development-Third Edition, and product measures were collected for running, jumping, hopping, kicking, and throwing. Moderate to vigorous PA was measured using wrist-worn ActiGraph accelerometers. Linear mixed models tested associations between FMS and PA changes, controlling for age, sex, and body mass index and accounting for preschool center differences. RESULTS:Improvements in locomotor skills were positively associated with increased moderate to vigorous PA postintervention, whereas improvements in object control skills were negatively associated with moderate to vigorous PA at the same time point. No significant prospective associations were observed. CONCLUSION:These findings suggest that locomotor skill gains may support short-term PA among preschoolers, but further research is needed to clarify additional aspects of the FMS-PA relationship after motor skill interventions.
Purpose: To compare exercise testing results of pediatric patients with postural orthostatic tachycardia syndrome (POTS) and orthostatic intolerance (OI) with those of healthy peers and investigate differences in heart rate (HR) kinetics during and after exercise testing. Methods: Analysis of maximal exercise data using the Bruce protocol. HR kinetics were analyzed during exercise by comparing the percentage of test completion with percentage of maximal HR and in recovery by calculating HR recovery postcardiopulmonary exercise testing. Results: A total of 222 patients aged 15.9 (1.7) years participated in this study. POTS and OI patients had worse HR metrics, exercise duration, peak aerobic capacity, and percentage predicted peak aerobic capacity compared with peers. POTS and OI patients had elevated HR responses at 10%, 25%, and 50% of cardiopulmonary exercise testing duration compared with healthy peers. Furthermore, POTS and OI patients had reduced HR recovery at 3, 4, 5, 9, and 10 minutes postcardiopulmonary exercise testing compared with peers. Conclusions: Pediatric POTS and OI patients have decreased exercise capacity, exaggerated submaximal HR responses, and blunted HR recovery compared with healthy peers. Exercise capacity and HR kinetics did not differ between POTS and OI patients. Decreased time to peak HR may explain some of the exercise intolerance observed in pediatric patients with POTS and OI and may be a helpful metric for exercise prescription and outcome tracking.
PURPOSE:The purpose of this study was to explore whether incorporating gyroscopic and accelerometer data will improve the prediction of energy expenditure (EE) of preschool children. Three model configurations were developed and compared using (1) accelerometer, (2) gyroscope, and (3) accelerometer + gyroscope data (dual sensor). METHOD:Participants (n = 39; aged 3 to <6 years) were equipped with OPAL, GT9X, and GENEActiv devices, worn on the right hip, right wrist, and left wrist, while EE was simultaneously measured using a portable metabolic unit. The protocol consisted of semistructured activities spanning a range of intensities from low to high. A total of 54 machine learning models were developed to predict EE (2 EE measures [metabolic equivalents, kilojoules per minute] × 3 wear locations × 3 model types [random forest, linear regression, and fully connected neural network] × 3 sensor configurations). Model performance was evaluated using root mean squared error. RESULTS:Our findings reveal that, across the various configurations, the random forest model utilizing dual-sensor data achieved marginally lower mean root mean squared error in the majority of cases. CONCLUSION:Given the minimal improvements observed and the challenges associated with data acquisition, we recommend that researchers utilize accelerometer-based models moving forward.
PURPOSE:This study aimed to identify the injury profiles of Korean youth soccer players over a 1-year period. METHOD:One hundred Korean male soccer players aged 12-15 years were recruited for this prospective epidemiological study. Data on injury characteristics, including the type of field, severity of injuries, time to return to full soccer activities, re-injury rate, and surgery rate were collected by the medical staff. The incidence rate of injuries including body locations, types, and causes was calculated as the number of injuries per 1000 hours. RESULTS:In total, 140 injuries were reported during the 1-year follow-up. The overall incidence rate was 5.76 per 1000 hours. The incidence rate was higher during matches than during training (14.76 per 1000 h vs 3.88 per 1000 h). The most common body location, type of injury, and cause of injuries were the ankle (n = 46, 32.9%), ligament sprain (n = 54, 37.1%), and noncontact injury (n = 63, 45.0%), respectively. CONCLUSIONS:Prevention strategies should focus on noncontact ankle sprains in Korean youth soccer players. Given the growth spurts experienced by U-15 soccer players, emphasis should be placed on muscle conditioning and balance training to control movement and prevent soccer injuries.
This study evaluated the effects of a 12-week home-based physical activity program on functional mobility, cancer-related fatigue, and muscle strength in children and adolescents with cancer undergoing active treatment. The uncontrolled clinical trial included 25 participants (14 boys), aged 4-14 years, who utilized physical activity notebooks (Physical Activity Journals 1 for ages 4-11/Physical Activity Journal 2 for ages 12-14). Functional mobility, assessed using the Timed Up and Go test, demonstrated a significant reduction in time (P < .001) in the per-protocol analysis, whereas the intention-to-treat analysis showed no significant differences (P > .1). Cancer-related fatigue, measured by the Pediatric Quality of Life Inventory, revealed significant reductions in total fatigue scores for both per-protocol (P = .038) and intention-to-treat (P = .039) analyses. Although no statistical differences were observed in the sleep, mental, or general fatigue domains, a clinically meaningful reduction in fatigue symptoms was identified. Muscle strength, evaluated with a portable dynamometer, displayed statistically significant improvements in specific muscle groups in both per-protocol and intention-to-treat analyses. In conclusion, the home-based intervention using activity notebooks effectively improved functional mobility, reduced fatigue in certain domains, and enhanced muscle strength, yielding important clinical benefits for this population.
Purpose : This study examines the proportion of children and adolescents in Fiji meeting the Asia-Pacific physical activity (PA) and screen time (ST) recommendations, and to explore associated factors. Method : A cross-sectional sample of caregivers (n = 1015) and their children aged 5–17 years completed an online survey based on Ajzen’s conceptualization of attitudes within the Theory of Planned Behavior. Data included meeting PA and ST behaviors recommendations, sociodemographic factors, knowledge of recommendations, and attitudes toward meeting PA and ST recommendations. Generalized linear mixed models were used to identify factors associated with meeting recommendations. Results : 53% of children met both PA and ST recommendations, 87% met PA recommendations, and 62% met ST recommendations. Girls (odds ratio [OR] = 0.568; 95% CI, 0.360–0.896) had lower odds of meeting PA recommendations compared with boys. Children with less positive attitudes toward PA were less likely to meet PA recommendations (OR = 0.520; 95% CI, 0.312–0.868) compared with those with the most positive attitude. Children who live in rural (OR = 1.900; 95% CI, 1.233–2.929) and remote/very remote (OR = 1.681; 95% CI, 1.128–2.505) had higher odds of meeting ST recommendations compared to urban children. Children who speak English (OR = 0.567; 95% CI, 0.399–0.806) and Fijian-Hindi speakers (OR = 0.644; 95% CI, 0.469–0.883) had lower odds of meeting ST recommendations versus iTaukei/Fijian speakers. Conclusion : There is a need for targeted interventions promoting PA among girls and addressing ST across demographic groups.
Monitoring weekly training load (WTL) is essential in youth soccer; however, the influence of contextual factors on WTL during the microcycle remains unclear. OBJECTIVE:The aim of this study was to (1) analyze the effect of match-related contextual factors, such as match location, and opponent standard on WTL in elite youth soccer players across a competitive season, and (2) compare session and WTLs according to the number of training sessions per microcycle. METHODS:Training and match data were collected from 46 male soccer players of a Spanish First Division academy. External load variables were obtained using Global Positioning System, including total distance covered, high-speed distance (>18 km·h-1), sprint distance (>21 km·h-1), the number of high metabolic load efforts (>20 W·Kg-1), and player load. Training weeks were categorized based on contextual factors, such as match location, opponent level, and the number of training sessions in the microcycle (3, 4, or 5 sessions per week, W3s, W4s, W5s, respectively). RESULTS:WTL significantly increased (P < .05) in sprint distance weeks before playing away compared with playing at home. In reference to the length of the microcycle, W3s showed a significant decrease (P < .01) in WTL than W4s and W5s in all metrics. Additionally, W5s had significantly greater WTL for total distance covered, player load, and power score than W4s (P < .01). CONCLUSIONS:Match location was the only contextual factor affecting WTL, highlighting the importance of considering its impact when planning training load, as it may influence recovery, fatigue, and overall training strategies.
