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Meyer F O'Connor H Shirreffs SM;International Association of Athletics Federations 《Journal of sports sciences》2007,25(Z1):S73-S82
Athletics is a popular sport among young people. To maintain health and optimize growth and athletic performance, young athletes need to consume an appropriate diet. Unfortunately, the dietary intake of many young athletes follows population trends rather than public health or sports nutrition recommendations. To optimize performance in some disciplines, young athletes may strive to achieve a lower body weight or body fat content and this may increase their risk for delayed growth and maturation, amenorrhoea, reduced bone density, and eating disorders. Although many of the sports nutrition principles identified for adults are similar to those for young athletes, there are some important differences. These include a higher metabolic cost of locomotion and preferential fat oxidation in young athletes during exercise. Young athletes, particularity children, are at a thermoregulatory disadvantage due to a higher surface area to weight ratio, a slower acclimatization, and lower sweating rate. An appropriate dietary intake rather than use of supplements (except when clinically indicated) is recommended to ensure young athletes participate fully and safely in athletics. 相似文献
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The effects of ability grouping in schools on students' self-concept were examined in a sample of 23 secondary schools with a range of structured ability groupings. Measures of general self-concept, academic self-concept, and achievement were collected from over 1600 students aged 14–15 years and again two years later. Students' academic self-concept, but not their general self-concept, was related to the extent of ability grouping in the school attended. Subject-specific facets of academic self-concept were not related to the number of years of ability grouping students had experienced in English, mathematics and science; however, they were related to students' position in the grouping hierarchy, with students in high-ability groups having significantly higher self-concepts in all three subjects than students in low-ability groups. Students' intentions to learn in future were more strongly affected by self-concept than by achievement. 相似文献
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