Suchergebnisse

Only one fifth of children aged 11–17 years are physically active for 60 min (min)/day. As physical activity (PA) levels track from childhood to adulthood, it is important to establish healthy PA behavior early in life. This study aims to evaluate whether daily school PA is associated with objectively measured PA independently of other socioecological factors. This study includes 209 children (120 boys) aged 9.8 ± 0.6 (mean ± SD) years from four government-funded schools in Sweden. One school including 113 children (70 boys) had 40 min of daily school PA (intervention) and three schools including 96 children (50 boys) had 60 min of school PA/week (control). PA was measured during four serial days with accelerometers. General PA (GPA) was defined as mean counts per minute (cpm). Socioecological factors were collected by questionnaires, and anthropometric traits by measurements. Analysis of covariance (ANCOVA) was used to test whether sex, age, relative age, body height, fat mass, lean mass, screen time activity, parental educational level, parental attitude towards PA, parental PA, sibling(s)' PA, living in a house or apartment, and whether the child was allocated to 40 min daily school PA or 60 min school PA/week, was independently associated with GPA. Daily GPA was found to be 686.9 ± 211.9 cpm. Independently of the other included factors, daily school PA was associated with +81.8 (15.7, 147.8) cpm compared with 60 min PA/week. This study infers that daily school PA is an appropriate strategy to promote PA in 10-year-old children, independently of different socioecological factors.

Only one fifth of children aged 11–17 years are physically active for 60 min (min)/day. As physical activity (PA) levels track from childhood to adulthood, it is important to establish healthy PA behavior early in life. This study aims to evaluate whether daily school PA is associated with objectively measured PA independently of other socioecological factors. This study includes 209 children (120 boys) aged 9.8 ± 0.6 (mean ± SD) years from four government-funded schools in Sweden. One school including 113 children (70 boys) had 40 min of daily school PA (intervention) and three schools including 96 children (50 boys) had 60 min of school PA/week (control). PA was measured during four serial days with accelerometers. General PA (GPA) was defined as mean counts per minute (cpm). Socioecological factors were collected by questionnaires, and anthropometric traits by measurements. Analysis of covariance (ANCOVA) was used to test whether sex, age, relative age, body height, fat mass, lean mass, screen time activity, parental educational level, parental attitude towards PA, parental PA, sibling(s)' PA, living in a house or apartment, and whether the child was allocated to 40 min daily school PA or 60 min school PA/week, was independently associated with GPA. Daily GPA was found to be 686.9 ± 211.9 cpm. Independently of the other included factors, daily school PA was associated with +81.8 (15.7, 147.8) cpm compared with 60 min PA/week. This study infers that daily school PA is an appropriate strategy to promote PA in 10-year-old children, independently of different socioecological factors.

The longitudinal and multidisciplinary research project Malmö Youth Sport Study measured the sports results achieved by two cohorts of pupils using a variable named ACHIEVE, dividing the pupils into three categories (an elite group competing at the national or international level, a group competing at the district level, and a third group either not competing at all or below district level). This was assessed three and six years after baseline at age 13. An additional hypothetical measure, based on information from the athletes' trainers, predicted the category the pupils were expected to belong to after twelve years (age 25). Social variables related to the ACHIEVE variable are sex, socio-economic position of the parents, ethnicity, completed secondary sports school, sports capital, and quartile of birth. After three years, 28% of the pupils belonged to the elite group and after six years, 26%. Thirty-two and 48%, respectively, had abandoned their elite efforts. The elite group remained fairly stable over time but fewer girls than boys advanced to the elite group. The pupils at the school have a homogenous middle-class background. We found little evidence that socio-economic factors affected ACHIEVE. Nearly all parents had been engaged in sports, either competing or as coaches. On admission to the school, there was a pronounced relative age effect (RAE). This remained after three years as the age was significantly different between the three groups but was reduced after six years. According to the prognosis made by the coaches, the elite group would be considerably smaller when the subjects reached the age of 25. The RAE was again significant in the prognosis. A further follow-up when the subjects are 25 years old will reveal not only what proportion of subjects are actively competing, but also if they are engaged in recreational sports, to what extent the RAE is present, and how accurately coaches can predict success.

This 7.5-year prospective controlled exercise intervention study assessed if daily school physical activity (PA), from before to after puberty, improved musculoskeletal traits. There were 63 boys and 34 girls in the intervention group (40 min PA/day), and 26 boys and 17 girls in the control group (60 min PA/week). We measured musculoskeletal traits at the start and end of the study. The overall musculoskeletal effect of PA was also estimated by a composite score (mean Z-score of the lumbar spine bone mineral content (BMC), bone area (BA), total body lean mass (TBLM), calcaneal ultrasound (speed of sound (SOS)), and muscle strength (knee flexion peak torque)). We used analyses of covariance (ANCOVA) for group comparisons. Compared to the gender-matched control group, intervention boys reached higher gains in BMC, BA, muscle strength, as well as in the composite score, and intervention girls higher gains in BMC, BA, SOS, as well as in the composite score (all p < 0.05, respectively). Our small sample study indicates that a daily school-based PA intervention program from Tanner stage 1 to 5 in both sexes is associated with greater bone mineral accrual, greater gain in bone size, and a greater gain in a musculoskeletal composite score for fractures.

The relationship between birth quarter distribution and physiological characteristics related to athletic skills, in adolescent sport academy students has not been fully investigated. In a cross-sectional study, we recruited 86 boys and 52 girls aged 12–14 years during their first term at a sport academy school. We measured body size, cardiac size, pulmonary function, body composition, lower body power, cardiorespiratory fitness parameters, and running endurance by standard methods and analyzed these estimates in relation to birth quarter by ANOVA. Birth quarter distribution in our cohort was compared with birth quarter distribution in the same ages in the whole of Sweden and analyzed by logistic regression. The academy had an overrepresentation of students born in the first quartile of the year compared to those born in the last quartile (odds ratio 2.3 (95% CI: 1.1–4.7)). When comparing the physiological characteristics between birth quarters, uniformity is prominent since out of 26 performed physiological and anthropometric tests only four showed statistically significant group differences. We thus believe that the selection process to the sport academy favours athletes with higher chronological age, i.e., a so-called relative age effect is present.