The aim of this study was to examine spatiotemporal characteristics and joint angles during forward and backward walking in water at low and high stride frequency. Eight healthy adults (22.1 ± 1.1 years) walked forward and backward underwater at low (50 pulses) and high frequency (80 pulses) at the xiphoid process level with arms crossed at the chest. The main differences observed were that the participants presented a greater speed (0.58 vs. 0.85 m/s) and more asymmetry of the step length (1.24 vs. 1.48) at high frequency whilst the stride and step length (0.84 vs. 0.7 m and 0.43 vs. 0.35 m, respectively) were lower compared to low frequency (P < 0.05). Support phase duration was higher at forward walking than backward walking (61.2 vs. 59.0%). At initial contact, we showed that during forward walking, the ankle and hip presented more flexion than during backward walking (ankle: 84.0 vs. 91.8º and hip: 22.8 vs. 8.0º; P < 0.001). At final stance, the knee and hip were more flexed at low frequency than at high frequency (knee: 150.0 vs. 157.0º and hip: ?12.2 vs. –14.5º; P < 0.001). The knee angle showed more flexion at forward walking (134.0º) than backward walking (173.1º) (P < 0.001). In conclusion, these results show how forward and backward walking in water at different frequencies differ and contribute to a better understanding of this activity in training and rehabilitation. 相似文献
The purpose of this study was to investigate the effects of interval aerobic training combined with strength exercise in the same training session on body composition, and glycaemic and lipid profile in obese rats. Sixteen lean Zucker rats and sixteen obese Zucker rats were randomly divided into exercise and sedentary subgroups (4 groups, n = 8). Exercise consisted of interval aerobic training combined with strength exercise in the same training session. The animals trained 60 min/day, 5 days/week for 8 weeks. Body composition, lipid and glycaemic profiles and inflammatory markers were assessed.
Results showed that fat mass was reduced in both lean and obese rats following the exercise training (effect size (95% confidence interval (CI)) = 1.8 (0.5–3.0)). Plasma low-density lipoprotein–cholesterol and fasting glucose were lower in the exercise compared to the sedentary groups (d = 2.0 (0.7–3.2) and 1.8 (0.5–3.0), respectively). Plasma insulin was reduced in exercise compared to sedentary groups (d = 2.1 (0.8–3.4)). Some exercise × phenotype interactions showed that the highest decreases in insulin, homeostatic model assessment-insulin resistance, fasting and postprandial glucose were observed in the obese + exercise group (all, P < 0.01). The findings of this study suggest that interval aerobic training combined with strength exercise would improve body composition, and lipid and glycaemic profiles, especially in obese rats. 相似文献
Testing is one of the important tasks in any multi-step sport programme. In most ball games, coaches assess motor, physical and technical skills on a regular basis in early stages of talent identification in order to further athletes’ development. The purpose of the study was to investigate anthropometric variables and vertical jump heights as a free throw effectiveness predictor in water-polo players of different age groups. Two hundred and thirty-six young (10–18 years) male water-polo players partitioned into three age groups underwent anthropometric variables’ measures and squat- and countermovement-jump tests, and performed water-polo free throws. Anthropometric variables, vertical jump heights and throw speed – as a proxy for free throw effectiveness – resulted different over age groups. Particularly, throw speed changed from 9.28 to 13.70 m · s?1 (+48%) from younger to older players. A multiple-regression model indicated that body height, squat-jump height and throw time together explain 52% of variance of throw speed. In conclusion, tall height, high lower limb power and throwing quickness appeared to be relevant determinants for effective free throws. Such indications can help coaches during talent identification and development processes, even by means of novel training strategies. Further research is needed over different maturity statuses. 相似文献
ABSTRACTThe objective of this 1-year, longitudinal study was to examine the development of perceived competence, tactical skills, motivation, technical skills, and speed and agility characteristics of young Finnish soccer players. We also examined associations between latent growth models of perceived competence and other recorded variables. Participants were 288 competitive male soccer players ranging from 12 to 14 years (12.7 ± 0.6) from 16 soccer clubs. Players completed the self-assessments of perceived competence, tactical skills, and motivation, and participated in technical, and speed and agility tests. Results of this study showed that players’ levels of perceived competence, tactical skills, motivation, technical skills, and speed and agility characteristics remained relatively high and stable across the period of 1 year. Positive relationships were found between these levels and changes in perceived competence and motivation, and levels of perceived competence and speed and agility characteristics. Together these results illustrate the multi-dimensional nature of talent development processes in soccer. Moreover, it seems crucial in coaching to support the development of perceived competence and motivation in young soccer players and that it might be even more important in later maturing players. 相似文献
ABSTRACTStuart Hall’s work on culture, representation, ideology and hegemony positions Hollywood as a cultural institution informed by and informative of US social values and norms. Thus contemporary debates over Hollywood's diversity are indicative of broader social conflicts. Empirically the article examines 2014–2015 news coverage of Hollywood to question the Hollywood paradox—the lack of diversity in film/TV production yet TV’s increasing shift towards on-screen diversity. It maps three discursive frames: Hollywood exceptionalism, economic imperatives, and institutionalized racism and sexism. The article concludes by using Hulu’s East Los High to reflect on TV’s digital turn and innovative models in production and representation. 相似文献
Psychobiology is an area of knowledge that deals with the biological basis of behaviour. Its concretion as a specific area of study originates in the confluence and development of other areas such as physiological psychology, experimental and comparative psychology, ethology, biology and the neurosciences. For some, psychobiology would be that part of the neurosciences that deals with the study of the processes of emotion, motivation, cognition and learning. Others are of the opinion that it covers a much wider area, and that its objective is rooted in the study of all biological mechanisms that govern behaviour — and these, undertaken from a philogenetic and ontogenetic perspective.
In the last decade, we have witnessed the creation of psychobiology departments throughout the world. These departments participate in the teaching of faculties of medicine, psychology, biology and zoology. In some universities, these departments even contribute to the teaching imparted by the faculties of philosophy and educational sciences. Sooner or later, the universities teaching at a distance had to consider the creation of departments of psychobiology to attend to the up‐dating of the curriculum of diversive faculties.
In the National University of Education at a Distance, U.N.E.D. (Madrid, Spain) the teaching of psychobiology is entrusted to a department of the same name which started during the academic year of 1982–83. Even though the experience is very short to be able to advance a complete evaluation, the difficulties encountered in the organization of the form and content of different courses imparted by the department of psychobiology (D.P.) could be useful to the reader. Therefore, these difficulties must be understood within the educational model of teaching at a distance at U.N.E.D. 相似文献
Reading and Writing - The present study investigates the effectiveness of question paraphrases in supporting students’ understanding of a specific task. Secondary school students (i.e.,... 相似文献
University rankers are the subject of much criticism, and yet they remain influential in the field of higher education. Drawing from a two-year field study of university ranking organizations, interviews with key correspondents in the sector, and an analysis of related documents, I introduce the concept of weak expertise. This kind of expertise is the result of a constantly negotiated balance between the relevance, reliability, and robustness of rankers’ data and their relationships with their key readers and audiences. Building this expertise entails collecting robust data, presenting it in ways that are relevant to audiences, and engaging with critics. I show how one ranking organization, the Times Higher Education (THE), sought to maintain its legitimacy in the face of opposition from important stakeholders and how it sought to introduce a new “Innovation and Impact” ranking. The paper analyzes the strategies, methods, and particular practices that university rankers undertake to legitimate their knowledge—and is the first work to do so using insights gathered alongside the operations of one of the ranking agencies as well as from the rankings’ conference circuit. Rather than assuming that all of these trust-building mechanisms have solidified the hold of the THE over its audience, they can be seen as signs of a constant struggle for influence over a skeptical audience. 相似文献