Joey C. Eisenmann

Maturity-associated variation in the growth and functional capacities of youth football (soccer) players 13-15 years

The objective was to estimate the contribution of experience, body size and maturity status to variation in the functional capacities of adolescent football (soccer) players. The sample included 69 players 13.2–15.1xa0years of age from three clubs which competed in the highest division for their age group in the first Portuguese national division. Height and weight were measured and stage of pubic hair development was assessed at clinical examination. The number of years of experience in football was obtained at interview. Three tests of functional capacity were administered: 30-m dash (running speed), vertical jump (explosive power) and a yo-yo intermittent endurance test (aerobic resistance). Multiple linear regression analysis was used to estimate the relative contributions of age, stage of sexual maturity, height, weight and years of formal training in football to the three indicators of functional capacity. Stage of puberty, body size and years of training accounted for 21% to 50% of the variance in the three tasks. Sexual maturity status was the primary contributor to the variance in the intermittent shuttle run, whereas weight and height were the primary contributors to the explained variance in the 30-m dash and vertical jump, respectively. In conclusion, biological maturity status significantly influences the functional capacity of adolescent football players 13–15xa0years of age. Training is a significant contributor to aerobic resistance, whereas weight and height are significant contributors to the sprint and vertical jump, respectively.

Field Validation of the MTI Actigraph and BodyMedia Armband Monitor Using the IDEEA Monitor

Objective: Accelerometers offer considerable promise for improving estimates of physical activity (PA) and energy expenditure (EE) in free‐living subjects. Differences in calibration equations and cut‐off points have made it difficult to determine the most accurate way to process these data. The objective of this study was to compare the accuracy of various calibration equations and algorithms that are currently used with the MTI Actigraph (MTI) and the Sensewear Pro II (SP2) armband monitor.

Sleep duration and overweight among Australian children and adolescents

Aim: To examine the association between sleep and overweight and waist circumference (WC) in children and adolescents. Methods: Data were from a nationally representative sample of 6324 7–15‐y‐old males and females from the Australian Health and Fitness Survey. Associations between sleep duration and body mass index (BMI) and WC were examined by analysis of covariance, linear regression, and logistic regression. Results: In the total sample, there was a significant main effect across sleep‐duration categories (≤8 h, 8–9 h, 9–10 h, and ≥10 h) for BMI. Linear regression showed significant age, sex, age‐sleep, and age‐sex‐sleep interactions in the total sample. There was an inverse graded relationship between sleep and BMI and WC in boys. In boys, there was a 1.6–1.8 times greater odds of overweight for those who reported 8–9 h or 9–10 h of sleep compared to those reporting ≥10 h of sleep. For boys reporting ≤8 h of sleep, there was about 3.1 times greater odds of overweight compared to those reporting ≥10 h of sleep. In contrast, no significant associations between sleep and overweight were found in girls.

Aerobic fitness, body mass index, and CVD risk factors among adolescents: the Québec family study.

PURPOSE:The purpose of this study was to examine the association of body mass index (BMI) and aerobic fitness on cardiovascular disease (CVD) risk factors in adolescents.METHODS:The sample included 416 boys and 345 girls 9–18u2009y of age from the Québec Family Study. Participants were cross-tabulated into four groups using a median split of age-adjusted physical working capacity (PWC) and body mass index (BMI). Group differences in age-adjusted CVD risk factors (blood pressures, fasting total cholesterol (CHOL), LDL -C, HDL-C, HDL/CHOL, triglycerides, glucose, and a composite risk factor score) were examined by two-way ANOVA.RESULTS:Several CVD risk factors showed significant main effects for PWC, BMI and/or the PWC by BMI interaction. In general, low fit males and females had higher blood lipids and glucose compared to their high fit counterparts within BMI categories although none of the differences reached statistical significance. The high fit/low BMI group showed the best CVD risk factor profile while the low fit/high BMI showed a poorer profile as evidenced by several significant differences between these two groups. Other significant differences occurred for various risk factors between groups.CONCLUSION:Both aerobic fitness and BMI show an independent association with CVD risk factors in adolescents.

Combined Influence of Physical Activity and Screen Time Recommendations on Childhood Overweight

OBJECTIVESnTo examine the combined influence of physical activity and screen time (television and video games) on the odds of being overweight and to evaluate the utility of current public policy recommendations.nnnSTUDY DESIGNnPhysical activity was assessed by a pedometer and screen time was assessed by survey in a sample of 709 children age 7 to 12 years. The percentage of subjects meeting current physical activity and screen time recommendations was calculated. Cross-tabulated physical activity-screen time groups were formed depending on whether or not the children were meeting current recommendations. Logistic regression was used to examine the influence of physical activity and screen time on the odds of being overweight.nnnRESULTSnChildren meeting physical activity and screen time recommendations were the least likely to be overweight. Approximately 10% of the boys and 20% of the girls meeting both recommendations were overweight, compared with 35% to 40% of those who did not meet either recommendation. Screen time and physical activity appeared to be equivalent risk factors for boys, even though physical activity in girls was more strongly associated with body mass index.nnnCONCLUSIONSnChildren not meeting the physical activity or screen time recommendations were 3 to 4 times more likely to be overweight than those complying with both recommendations.

Maturity-associated variation in sport-specific skills of youth soccer players aged 13-15 years.

The aim of this study was to estimate the contribution of experience, body size and maturity status to variation in sport-specific skills of adolescent soccer players. The participants were 69 players aged 13.2u200a–u200a15.1 years from three clubs that competed in the highest division for their age group. Height and body mass were measured and stage of pubic hair development was assessed at clinical examination. Years of experience in football was obtained at interview. Six football skill tests were administered: ball control with the body, ball control with the head, dribbling with a pass, dribbling speed, shooting accuracy and passing accuracy. Multiple linear regression analysis was used to estimate the relative contributions of age, stage of sexual maturity, height, body mass and years of formal training in soccer to the six skill tests. Age, experience, body size and stage of puberty contributed significantly but in different combinations to the variance in four of the six skill tests: dribbling with a pass (21%; age, stage of maturity), ball control with the head (14%; stage of maturity, height, body height × body mass interaction), ball control with the body (13%; stage of maturity, years of training) and shooting accuracy (8%; stage of maturity, height; borderline significance, Pu200a=u200a0.06). There were no significant predictors for the tests of dribbling speed and passing accuracy. In conclusion, age, experience, body size and stage of puberty contributed relatively little to variation in performance in four of the six soccer-specific skill tests in adolescent footballers aged 13u200a–u200a15 years.

Waist circumference percentiles for 7- to 15-year-old Australian children

A letter to the editor is presented in response to the article about waist circumference percentiles for seven to fifteen-year-old Australian children, that was published in the previous issue of the journal.

Aerobic Fitness Attenuates the Metabolic Syndrome Score in Normal-Weight, at-Risk-for-Overweight, and Overweight Children

OBJECTIVE. The purpose of this study was to examine the combined influence of aerobic fitness and BMI on the metabolic syndrome score in children. METHODS. A total of 375 children (193 girls and 182 boys) aged 7 to 9 years were categorized as being normal weight, at risk for overweight, and overweight on the basis of BMI and aerobic fitness (high or low based on median split) via a submaximal physical working capacity test. Participants were cross-tabulated into 6 BMI fitness categories. High-density lipoprotein cholesterol and triglyceride levels, homeostasis assessment model of insulin resistance, mean arterial pressure, and waist circumference were used to create a continuous metabolic syndrome score. RESULTS. Both BMI and fitness were associated with the metabolic syndrome score. In general, the metabolic syndrome score increased across the cross-tabulated groups with the normal-weight, high-fit group possessing the lowest metabolic syndrome score and the overweight, unfit group possessing the highest metabolic syndrome score. Children who were at risk for overweight and had high fitness had a lower metabolic syndrome score compared with those at-risk-for-overweight, less-fit children, and the score was similar to that of the less-fit, normal-weight children. Furthermore, a high fitness level resulted in a lower metabolic syndrome score in overweight children compared with overweight children with low fitness. CONCLUSIONS. High fitness levels modified the impact that BMI had on the metabolic syndrome score in children. Increasing a childs fitness level could be one method for reducing the risk of obesity-related comorbidities.

Aerobic fitness, fatness and the metabolic syndrome in children and adolescents.

The paediatric obesity epidemic is well documented. Recently, there has also been the emergence of type 2 diabetes and the metabolic syndrome (MetS) among children and adolescents. Although it is well known that obesity is linked to the metabolic syndrome in youth, the role of physical activity and fitness on the metabolic syndrome is unclear. The purpose of this review was to examine the concepts of and associations between fitness, fatness and the MetS in children and adolescents. In general, the association between fatness and the MetS (or components of the MetS) is stronger than those for fitness. Furthermore, the correlation between fatness and the MetS remains significant after controlling for fitness, whereas the correlation between fitness and MetS does not remain significant after controlling for fatness. When subjects are cross‐tabulated into categories (fat‐fit, etc.), there is good evidence that fitness attenuates the MetS score among fat children and adolescents. The reasons for these observations possibly involve genetics, adipocytokines and mitochondrial function. Further study is needed to understand the role of physical activity and other environmental factors on this phenomena. In addition, longitudinal studies of the fat‐fit phenotype are required and should include measurements of the hormonal mileau, adipokines and the oxidative capacity of skeletal muscle during childhood and adolescence.

Physical activity levels in children and adolescents are reduced after the Fontan procedure, independent of exercise capacity, and are associated with lower perceived general health

Objectives: To determine physical activity levels in paediatric patients who underwent the Fontan procedure, and their relationship to functional status and exercise capacity. Study Design: We studied 147 patients (ages 7–18 years) at a median of 8.1 years after Fontan, as part of the Pediatric Heart Network cross-sectional study of Fontan survivors. Assessment included medical history, self-reported physical activity, parent-completed Child Health Questionnaire (CHQ), cardiopulmonary exercise testing and physical activity level measured by accelerometry (MTI Actigraph). Results: Measured time spent in moderate and vigorous activity was markedly below normal at all ages, particularly in females, and was not significantly related to self-reported activity levels, or to maximum Vo2, Vo2 at anaerobic threshold or maximum work rate on exercise testing. Lower measured activity levels were significantly related to lower perceived general health but not to self-esteem, physical functioning, social impact of physical limitations or overall physical or psychosocial health summary scores. Reduced exercise capacity was more strongly related than measured activity levels to lower scores in general health, self-esteem and physical functioning. Conclusions: Physical activity levels are reduced after Fontan, independent of exercise capacity, and are associated with lower perceived general health but not other aspects of functional status.