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Luisa Soares-Miranda Gavin Sandercock Susana Vale Pedro Silva Carla Moreira Rute Santos 《Journal of sports sciences》2013,31(10):1011-1018
Abstract The aim of this study was to examine differences in traditional heart rate variability measurements and heart rate complexity (sample entropy) in young adults grouped by objectively measured achievement of either moderate or both moderate and vigorous physical activity recommendations. Of 168 young adults tested (86 females, 82 males; age 20.5 ± 1.2 years), 119 achieved only recommendations for moderate physical activity (moderate group) and 49 achieved recommendations for both moderate and vigorous physical activity (vigorous group). Analysis of covariance controlling for sex, weekly minutes of moderate physical activity, and percentage of body fat was used to assess between-group differences in heart rate variability and heart rate complexity. Logistic regression analysis was used to determine the group characteristics that best predicted high heart rate complexity and vagal indices of heart rate variability. The majority of the autonomic measures were higher (P < 0.05) in the vigorous group, and regression analysis showed that vigorous physical activity was the only multivariate predictor of higher heart rate complexity and higher heart rate variability. Young adults engaged in regular vigorous physical activity were more than twice as likely to have high heart rate complexity than those involved in predominantly moderate exercise. These findings suggest that vigorous physical activity is more closely associated with high heart rate complexity than moderate physical activity in young adults. 相似文献
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Effective force and economy of triathletes and cyclists 总被引:1,自引:0,他引:1
Candotti CT Ribeiro J Soares DP De Oliveira AR Loss JF Guimarães AC 《Sports biomechanics / International Society of Biomechanics in Sports》2007,6(1):31-43
The effective force applied on the crank, the index of pedalling effectiveness, and the economy of movement at 60, 75, 90, and 105 rev/min cadences were examined in nine cyclists and eight triathletes. Tests were performed on two days. Maximal oxygen uptake was measured and the second ventilatory threshold was estimated on day 1 using a stationary bicycle. On day 2, the four different cadences were tested at about 5% below the second ventilatory threshold. A strain gauge instrumented clip-less pedal mounted on the bicycle enabled us to measure the normal and tangential forces exerted on the pedal, while the pedal and crank angles were monitored with the aid of a video system. Based on this information, the effective force and the index of pedalling effectiveness were calculated. Cyclists produced significantly more effective force and a higher index of pedalling effectiveness at 60 and 75 rev/min and were significantly more economic at all cadences than triathletes. The significant and positive correlation between effective force and economy at all cadences suggests that improvement of the effective force would reflect on economy. 相似文献
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Nicholas Denys Colclough Roger Lock Allan Soares 《International Journal of Science Education》2013,35(3):423-446
This study focussed on secondary school (11–18 years) pre‐service teachers’ (n = 73) knowledge of and attitudes towards risks associated with alpha, beta, and gamma radiations. A multi‐method approach was used with physics, chemistry, biology, and history graduates undertaking the one‐year initial teacher training, Post Graduate Certificate in Education course at a university in central England. A novel research tool, involving interviews about real concrete contexts and first‐hand data collection with radioactive sources, was employed to gain insights into a sub‐set of the sample (n = 12) of pre‐service teachers’ subject knowledge of and attitudes towards risk. The subject knowledge of all the pre‐service teachers was also measured using a Certainty of Response Index instrument; multiple‐choice questions with associated confidence indicators. Although the physicists displayed the higher levels of knowledge, they also demonstrated limitations in their knowledge and held misconceptions such as irradiation being confused with contamination. Physics graduates hold more rational attitudes and a greater willingness to accept risk while the attitudes of graduates in the other subject disciplines are more disparate. These findings raise questions about the extent to which pre‐service science and history teachers have the knowledge necessary to teach this topic. The article concludes with discussion of the implications these findings have for initial teacher training, continuing professional development needs for teachers already in the profession, and curriculum developers. 相似文献