Learning from animation enabled by collaboration

Animated graphics are extensively used in multimedia instructions explaining how natural or artificial dynamic systems work. As animation directly depicts spatial changes over time, it is legitimate to believe that animated graphics will improve comprehension over static graphics. However, the research failed to find clear evidence in favour of animation. Animation may also be used to promote interactions in computer-supported collaborative learning. In this setting as well, the empirical studies have not confirmed the benefits that one could intuitively expect from the use of animation. One explanation is that multimedia, including animated graphics, challenges human processing capacities, and in particular imposes a substantial working memory load. We designed an experimental study involving three between-subjects factors: the type of multimedia instruction (with static or animated graphics), the presence of snapshots of critical steps of the system (with or without snapshots) and the learning setting (individual or collaborative). The findings indicate that animation was overall beneficial to retention, while for transfer, only learners studying collaboratively benefited from animated over static graphics. Contrary to our expectations, the snapshots were marginally beneficial to learners studying individually and significantly detrimental to learners studying in dyads. The results are discussed within the multimedia comprehension framework in order to propose the conditions under which animation can benefit to learning.     

Managing time,workload and costs in distance education: findings from a literature review of Distances et Médiations des Savoirs (formerly Distances et Savoirs)

The purpose of this review, spanning over 12 years of publication of Distances et Médiations des Savoirs (DMS), formerly Distance et Savoirs (DMS) (2003–2014), is guided by the question why and how French-speaking researchers addressed the issues of time, workload and costs in distance learning, and how this was affected by the increasing influence of information and communication technologies.     

Évaluation-sondage dans le premier cycle (12–16 ans)

Sans résuméI.R.E.M. de Rouen     

教练员在培养优秀运运员过程中的作用

在过去的20年里,体育科研工作者努力探讨运动员如何才能成为最优秀的选手.他们认为,教练员在运动员发展过程中的作用不可忽视.     

Changes in mechanical properties of sprinting during repeated sprint in elite rugby sevens athletes

This study aimed to analyse fatigue-induced changes in mechanical sprinting properties during a specific repeated-sprint test in elite rugby sevens athletes. Twenty elite rugby sevens players performed ten 40?m sprints on a 30?s cycle with participant’s running back and forth in a marked lane. Radar was used to assess maximal overground sprint performance over each 40?m. Macroscopic mechanical properties (maximal horizontal force (F₀), maximal horizontal power (P_max), maximal ratio of horizontal force (RF_peak), decrease in the ratio of horizontal-to-total force (D_RF), total force and maximal sprinting velocity (v₀)) were drawn from horizontal force velocity relationships, using a validated method applied to the speed–time data. Fatigue-induced changes were analysed comparing the first sprint to an average of 2^nd-4^th, 5^th-7^th and 8^th-10^th. Repeated-sprint ability (RSA) testing induced substantial changes in the maximal velocity component, with a decrease (–15%) in v₀ (effect size (ES)?=?–2.46 to –4.98), and to a lower extent (–5.9%) in the maximal force component F₀ (ES?=?–0.59). D_RF moderately decreased (14%; ES=–0.76–1.11), and RF_peak largely decreased in the later sprints (ES?=?–0.32 to –1.27). Fatigue observed in this RSA test appeared to have a greater effect on the technical ability to produce horizontal force at high velocities, likely due to an alteration in the ability to maintain horizontally oriented force application when velocity increases rather than during the initial acceleration phase, but also the overall force production capacity. The ability to maintain forward-oriented force at high velocities is of central importance for identifying fatigue and monitoring load.     

Aerodynamic drag in cycling: methods of assessment

When cycling on level ground at a speed greater than 14 m/s, aerodynamic drag is the most important resistive force. About 90% of the total mechanical power output is necessary to overcome it. Aerodynamic drag is mainly affected by the effective frontal area which is the product of the projected frontal area and the coefficient of drag. The effective frontal area represents the position of the cyclist on the bicycle and the aerodynamics of the cyclist-bicycle system in this position. In order to optimise performance, estimation of these parameters is necessary. The aim of this study is to describe and comment on the methods used during the last 30 years for the evaluation of the effective frontal area and the projected frontal area in cycling, in both laboratory and actual conditions. Most of the field methods are not expensive and can be realised with few materials, providing valid results in comparison with the reference method in aerodynamics, the wind tunnel. Finally, knowledge of these parameters can be useful in practice or to create theoretical models of cycling performance.     

Evolution of fat oxidation during exercise in obese pubertal boys: Clinical implications

Abstract

In this study, we examined fat oxidation rates during exercise in obese pubescent boys. Three groups of pubescent boys (16 pre-pubescent, Tanner's stage I; 16 pubescent, Tanner's stage III; and 14 post-pubescent, Tanner's stage V) performed a graded test on a leg cycle ergometer. The first step of the test was fixed at 30 W and power was gradually increased by 20 W every 3.5 min. Oxygen consumption ([Vdot]O₂) and carbon dioxide production ([Vdot]CO₂) were determined as the means of measurements during the last 30 s of each step, which allowed us to calculate fat oxidation rates versus exercise intensity. Between 20 and 50% of peak oxygen consumption ([Vdot]O_2peak), fat oxidation rate in relative values (mg · min^?1 · kg FFM^?1) decreased continuously with pubertal development. In the same way, the maximum rate of fat oxidation occurred at a lower percentage of [Vdot]O_2peak (pre-pubescent: 49.47 ± 1.62%; pubescent: 47.43 ± 1.26%; post-pubescent: 45.00 ± 0.97%). Our results confirm that puberty is responsible for a decrease in fat free mass capacities to use fat during exercise. The results suggest that post-pubescent obese boys need to practise physical activity at a lower intensity than pre-pubescent boys to enhance lipolysis and diminish adipose tissue and the consequences of obesity.