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181.
Kerry McGawley Coline Van Waerbeke Karl-Johan Westberg Erik P.Andersson 《运动与健康科学(英文)》2022,11(1):21-29
Background:In a sprint cross-country(XC)ski competition,the difference in recovery times separating the first and the second semi-final(SF)heats from the final(F)may affect performance.The aim of the current study was to compare the effects of longer vs.shorter recovery periods prescribed between the 3 knock-out races of a simulated sprint XC ski competition involving a prologue(P),quarter-final(QF),SF,and F.Methods:Eleven well-trained XC ski athletes completed 2 simulated sprint XC ski competitions on a treadmill involving 4×883-m roller-ski bouts at a 4°incline using the gear 3 ski-skating sub-technique.The first 3 bouts were completed at a fixed speed(PFIX,QFFIX,and SFFIX)corresponding to~96%of each individual’s previously determined maximal effort.The final bout was performed as a self-paced sprint time trial(FSTT).Test conditions differed by the time durations prescribed between the QFFIX,SFFIX,and FSTT,which simulated real-world XC ski competition conditions using maximum(MAX-REC)or minimum(MIN-REC)recovery periods.Results:The FSTT was completed 5.4±5.5 s faster(p=0.009)during MAX-REC(179.2±18.1 s)compared to MIN-REC(184.6±20.0 s),and this was linked to a significantly higher power output(p=0.010)and total metabolic rate(p=0.009).The pre FSTT blood lactate(BLa)concentration was significantly lower during MAX-REC compared to MIN-REC(2.5±0.8 mmol/L vs.3.6±1.6 mmol/L,respectively;p=0.027),and the pre-to-post FSTT increase in BLa was greater(8.8±2.1 mmol/L vs.7.1±2.3 mmol/L,respectively;p=0.024).No other differences for MAX-REC vs.MIN-REC reached significance(p>0.05).Conclusion:Performance in a group of well-trained XC skiers is negatively affected when recovery times between sprint heats are minimized which,in competition conditions,would occur when selecting the last QF heat.This result is combined with a higher pre-race BLa concentration and a reduced rise in BLa concentration under shorter recovery conditions.These findings may help inform decision making when XC skiers are faced with selecting a QF heat within a sprint competition. 相似文献
182.
当今世界正以前所未有的速度发生着各种各样的变化。一些大的趋向,即所谓的世界大趋势,在一定程度上影响每个人的生活。科学、技术和创新在这个不断变化的世界中发挥着重要作用。科学素养比以往任何时候都更加重要。科技博物馆和科学中心作为公众参与科学技术的重要角色,面临着一系列的机遇和挑战。在不断变化的世界里,它们在提高公众科学素养方面能发挥什么作用?如何使它们在提高科学素养方面更具相关性和影响力?本文通过分析当前世界在全球化、人口变化、技术变革、信息爆炸、可持续发展等方面的现实,论述科学素养的必要性以及科技博物馆和科学中心在变化的世界中应该如何发挥作用。 相似文献
183.
Early home experiences of a group of 32 2-week old infants, equally divided according to social class, birth order, and sex, were studied. Naturalistic observations were taken on 2 consecutive days for a total of 6 hours. Compared with later-borns, firstborns received significantly more caretaker interaction on all variables studied. Compared with lower-SES infants, those from higher-SES homes received significantly more direct verbal interaction although the 2 groups did not differ on total periods of other types of caretaking interaction. The findings are consistent with birth order and social class differences reported in home environments of older infants and children. 相似文献
184.
Carl N. Johnson 《Child development》1997,68(6):1024-1026
Woolley rightly challenges the incredible idea, held by some adults, that it is children who are peculiarly fantastical in their thinking. However, Woolley expresses little appreciation for fantastical thinking as it underlies the capacity for both grand delusions and amazing insights. In reducing fantastical thinking to conceptual error, she overlooks the mythical underpinning of her own theorizing and neglects the many constructive roles of fantastical thinking in development. 相似文献
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Johnson MH 《Child development》2000,71(1):75-81
One future direction for cognitive development research involves a closer integration with our knowledge about the developing brain. I present a framework for analyzing and interpreting postnatal functional brain development in human infants. Three specific hypotheses contribute to this framework, within which a variety of phenomena associated with the neural basis of perception and cognition in normal and abnormal development can be characterized. 相似文献
187.
Many countries are trying to increase the recruitment to Science, Technology, Engineering and Mathematics (STEM) studies. Some have implemented curriculum reforms to this end, others may do so. Using experiences from curriculum reforms in Germany, the Netherlands and, in particular, Sweden, we consider a proposal from the Royal Society in England about a broader curriculum for 16–19-year-olds, involving more mathematics and science. In Sweden, a curriculum reform in 1995, for 16–20-year-olds, increased the academic content of vocational programmes, including mathematics and science, such that they provided eligibility to university studies. Another reform, in 2011, reinstated the distinctions between vocational and academic programmes and made courses yielding university eligibility compulsory for academic programmes only. Using longitudinal student population data for 1986–2017, we assess the reform outcomes through before-after comparisons. The 1995 reform was followed by decreased recruitment to STEM studies while the opposite was true for the 2011 reform. A reform in Germany requiring students to study more mathematics was not very successful, either. We connect the positive consequences following the 2011 reform to the extensive Swedish opportunities to change study path. Including the option to attend a 1-year ‘add-on’ education programme, enabling students with non-STEM upper secondary background to conduct STEM university studies, changes to STEM programmes dominate changes away from them. Accordingly, we recommend more, not less, flexibility in programme choice, preferably coupled with efforts to improve female STEM attitudes, which have proved effective in Sweden. 相似文献
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