Lead negatively affects human growth and development. In this research, we aimed to assess the effect of elevated blood lead level on age at menarche (AM), controlling for body mass index (BMI) and ...estimated fatness. The sample included 490 girls aged 7−16 examined in Polkowice town (Copper Basin, Poland) in 2008. Measurements included height, weight, skinfold thicknesses and estimated percentage of body fat. AM was assessed using the status quo method. Blood samples were taken for lead level assessment. Two groups were defined based on the median blood lead level for the total sample of children (3.7 µg/dL). Logistic regression models were used to assess the association between AM and independent variables. The results indicated that menarche in the higher blood lead level group was significantly later compared to the lower blood lead level group (p < 0.01). This relationship remained only marginally significant when BMI (p < 0.10), sum of skinfolds (p < 0.09) or percentage of fat (p < 0.08) were controlled. The results revealed that a lower blood lead level (3.7 µg/dL) than the currently acceptable threshold (5 µg/dL) is related to a later AM; however, this relationship is moderated by body fatness, which may decrease its significance.
Background: Participants in many youth sports are commonly combined into age groups spanning 2 years.
Aim: The study compared variation in size, function, sport-specific skill and goal orientation ...associated with differences in biological maturity status of youth soccer players within two competitive age groups.
Methods: The sample included 159 male soccer players in two competitive age groups, 11-12 years (n=87) and 13-14 years (n=72). Weight, height, sitting height and four skinfolds, four functional capacities, four soccer skills and goal orientation were measured. Skeletal maturity was assessed using the Fels method. Each player was classified as late, on time or early maturing based on the difference between skeletal and chronological ages. ANOVA was used to compare characteristics of players across maturity groups.
Results: Late, on time and early maturing boys are represented among 11-12-year-olds, but late maturing boys are under-represented among 13-14-year-olds. Players in each age group advanced in maturity are taller and heavier than those on time and late in skeletal maturity, but players of contrasting maturity status do not differ, with few exceptions, in functional capacities, soccer-specific skills and goal orientation.
Conclusion: Variation in body size associated with maturity status in youth soccer players is similar to that for adolescent males in general, but soccer players who vary in maturity status do not differ in functional capacities, soccer-specific skills and goal orientation.
Research considering physical activity (PA), physical inactivity and health outcomes among urban and rural youth has produced equivocal findings. This study examined PA, physical inactivity, ...sedentary behaviours and cardiorespiratory fitness (CRF) in adolescents from urban and rural communities in the Portuguese Midlands. The sample included 362 adolescents (165 males, 197 females) of 13-16 years of age. CRF was assessed by the PACER test. A GT1M accelerometer was used to record 5 consecutive days of PA and time spent sedentary. Analyses of covariance (chronological age as co-variate) were performed to test the effect of the area of residence on sedentary behaviour, PA and CRF. Urban youth of both sexes spent less time in sedentary activities than rural youth. Urban males were more active than rural peers at the weekend, whereas urban females were significantly less active than rural females on week days and across all days assessed. Rural youth of both sexes had higher levels of CRF than urban youth. Area of residence was related to aerobic fitness, PA and time spent in sedentary behaviours among Portuguese youth. Interventions seeking to enhance health and active lifestyles in Portuguese youth should consider the potential impact of socio-geographic factors.
Objective: To evaluate the growth, maturity status and functional capacity of youth soccer players grouped by level of skill. Subjects: The sample included 69 male players aged 13.2–15.1 years from ...clubs that competed in the highest division for their age group. Methods: Height and body mass of players were measured and stage of pubic hair (PH) was assessed at clinical examination. Years of experience in football were obtained at interview. Three tests of functional capacity were administered: dash, vertical jump and endurance shuttle run. Performances on six soccer-specific tests were converted to a composite score which was used to classify players into quintiles of skill. Multiple analysis of covariance, controlling for age, was used to test differences among skill groups in experience, growth status and functional capacity, whereas multiple linear regression analysis was used to estimate the relative contributions of age, years of training in soccer, stage of PH, height, body mass, the height×weight interaction and functional capacities to the composite skill score. Results: The skill groups differed significantly in the intermittent endurance run (p<0.05) but not in the other variables. Only the difference between the highest and lowest skill groups in the endurance shuttle run was significant. Most players in the highest (12 of 14) and high (11 of 14) skill groups were in stages PH 4 and PH 5. Pubertal status and height accounted for 21% of the variance in the skill score; adding aerobic resistance to the regression increased the variance in skill accounted for to 29%. In both regressions, the coefficient for height was negative. Conclusion: Adolescent soccer players aged 13–15 years classified by skill do not differ in age, experience, body size, speed and power, but differ in aerobic endurance, specifically at the extremes of skill. Stage of puberty and aerobic resistance (positive coefficients) and height (negative coefficient) are significant predictors of soccer skill (29% of the total explained variance), highlighting the inter-relationship of growth, maturity and functional characteristics of youth soccer players.
Growth and maturation impact the selection, development and progression of youth athletes. Individual differences in the growth and maturity may afford a performance advantage, clouding coaches and ...practitioners' perceptions regarding current ability and future potential. This may result in the exclusion of talented, yet less physically gifted athletes. Participants were 91 male (n = 47) and female (n = 44) elite British Junior tennis players, 8-17 years of age (12.5 ± 1.9 years). Height and body mass were measured and compared to growth charts; hand-wrist radiographs were taken. Skeletal age (SA) was estimated with the Fels method and contrasted to chronological age (CA). Mean height and body mass of individual players ranged between the 50th and 90th centiles for age and sex. Females were advanced in SA relative to CA (0.3-0.89 years.) from 8 years. Males were average to delayed in maturation from 8 to 12 years, but advanced in SA from 14 to 16 years (0.75-1.23 years). Individual differences in growth and maturation appear to contribute towards the selection of elite junior tennis players, with a bias towards males and females who are advanced in maturation and comparatively tall and heavy for their age. This has important implications for talent identification and development.
To present recommendations for the prevention, detection, and comprehensive management of disordered eating (DE) in athletes.
Athletes with DE rarely self-report their symptoms. They tend to deny the ...condition and are often resistant to referral and treatment. Thus, screenings and interventions must be handled skillfully by knowledgeable professionals to obtain desired outcomes. Certified athletic trainers have the capacity and responsibility to play active roles as integral members of the health care team. Their frequent daily interactions with athletes help to facilitate the level of medical surveillance necessary for early detection, timely referrals, treatment follow-through, and compliance.
These recommendations are intended to provide certified athletic trainers and others participating in the health maintenance and performance enhancement of athletes with specific knowledge and problem-solving skills to better prevent, detect, and manage DE. The individual biological, psychological, sociocultural, and familial factors for each athlete with DE result in widely different responses to intervention strategies, challenging the best that athletics programs have to offer in terms of resources and expertise. The complexity, time intensiveness, and expense of managing DE necessitate an interdisciplinary approach representing medicine, nutrition, mental health, athletic training, and athletics administration in order to facilitate early detection and treatment, make it easier for symptomatic athletes to ask for help, enhance the potential for full recovery, and satisfy medicolegal requirements. Of equal importance is establishing educational initiatives for preventing DE.
Background
To evaluate the concordance of skeletal age (SA) with two predicted estimates of biological maturity status in elite British youth tennis players.
Method
Participants were 71 male and ...female elite youth tennis players aged 8 to 16 years. Weight, height, and sitting height were measured. SA (Fels method) was the criterion indicator of maturity status. Maturity status was predicted with two methods: predicted age at peak height velocity and percentage of predicted adult height at the time of observation. Players were classified as late, average (on time), or early maturing with each method. Concordance of classifications was evaluated with kappa coefficients and Spearman’s rank order correlations.
Results
Kappa coefficients between maturity status classifications were low in both sexes, − 0.11 to 0.22, while Spearman’s rank order correlations between maturity status classifications based on SA and the percentage of predicted mature height were moderate in males (0.35) and females (0.25), but the corresponding correlations based on predicted age at peak height velocity (PHV) varied, moderate and negative in boys (− 0.37) and low and positive in girls (0.11). Concordance of maturity status classifications based on the prediction methods and SA among tennis players was thus limited.
Conclusions
Maturity status based on the percentage of predicted mature height at the time of observation correlated better with maturity status based on SA in contrast to status based on predicted age at PHV in this sample of elite youth tennis players.
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