Eksperimental'nye dannye i opyt ekspluatatsii pokazyvayut,chto k takim rezhimam otnositsya plavanie sudna v usloviyakh subgarmonicheskikh i supergarmonicheskikh rezonansnykh rezhimov.Prichinoy ikh vozniknoveniya yavlyaetsya nelineynoe vzaimodeystvie korpusa sudna i zhidkosti.

Results Among all children more recess PA and more time spent in SB related to academic skills were associated with a better reading fluency across Grades 1–3. In boys, higher levels of total PA, physically active school transportation and more time spent in SB related to academic skills were associated with a better reading fluency across the Grades 1–3. Among girls, higher levels of total PA were related to worse arithmetic skills across Grades 1–3. Moreover, total PA was directly associated with reading fluency and arithmetic skills in Grades 1–3 among girls whose parents had a university degree, whereas these relationships were inverse in girls of less educated parents.

Introduction Physical activity (PA), particularly physically active transportation, is decreasing, whereas sedentary behaviors, especially watching TV, sitting at the computer and playing video games, are increasing among children in developed countries –. This trend is a major public health problem because sedentary lifestyle in childhood has been found to increase the risk of chronic diseases in adulthood,. Adobe illustrator cs6 crack codes for games. The results of some cross-sectional studies suggest that lower levels of PA is associated with a poorer academic achievement among children –. Moreover, intervention studies have provided evidence that implementing 90 minutes of moderate-to-vigorous PA per week within a school day, adding 60 minutes of physical education per day or increasing after-school PA for 40 minutes per day improves academic achievement among children. However, some intervention and cross-sectional studies have reported only a weak or non-significant relationship between PA and academic achievement in children –.

One explanation for the inconsistent results of previous studies may be that various types of PA and sedentary behavior are differently related to academic achievement among children and adolescents. Some prior studies have found direct associations of physical education and extracurricular PA with academic achievement in children.

The results of one study suggested that engaging in sports is more strongly associated with academic achievement than total PA in adolescents. Moreover, one 20-minute bout of moderate-intensity PA has been shown to acutely improve performance in an academic achievement test in children,. However, there is limited evidence on the associations of other types of PA, such as physically active school transportation or recess PA with measures of academic achievement such as grades, standardized test scores or reading and arithmetic skills. Several studies have shown that acute and long-term PA improves cognitive functions, such as attention, concentration and working memory, which underlie academic achievement –.

Kamijo and co-workers and Chaddock-Heyman and colleagues showed an improved working memory and cognitive control, respectively, after a 9-month PA intervention in 8–9-year-old children. Moreover, Davis and associates reported enhanced executive functions after a 13-week PA intervention among overweight children. Trainz railroad simulator. There is also some evidence that PA during recess improves attention, concentration and on-task behavior in children,. In another study more time spent walking or bicycling to and from school was related to better cognitive functions independent of total PA in adolescents. Most studies on the associations of different types sedentary behavior with academic achievement have concentrated on screen-based sedentary behaviors such as watching TV and playing with the computer.

Whereas one study found an inverse association between TV watching and academic achievement in children and adolescents, another study suggested that a longer time spent watching TV was related to a better academic achievement in children. Screen time was inversely related to grade-point average but total sedentary time was not associated with academic achievement in Finnish children. Having a TV set in the bedroom has also been associated with a poorer academic achievement. Access to a home computer, however, has been associated with an improved academic achievement in 8-year-old children. Only a few cross-sectional studies have compared different types of PA and sedentary behavior in relation to measures of academic achievement such as reading and arithmetic skills among children and adolescents. Moreover, there are no follow-up studies on these topics in these age groups.