Neural mechanisms of strength increase after one-week motor imagery training

The neural mechanisms explaining strength increase following mental training by motor imagery (MI) are not clearly understood. While gains are mostly attributed to cortical reorganization, the sub-cortical adaptations have never been investigated. The present study investigated the effects of MI training on muscle force capacity and the related spinal and supraspinal mechanisms. Eighteen young healthy participants (mean age: 22.5?±?2.6) took part in the experiment. They were distributed into two groups: a control group (n?=?9) and an MI training group (n?=?9). The MI group performed seven consecutive sessions (one per day) of imagined maximal isometric plantar flexion (4 blocks of 25 trials per session). The control group did not engage in any physical or mental training. Both groups were tested for the isometric maximal plantar flexion torque (MVC) and the rate of torque development (RTD) before and after the training session. In addition, soleus and medial gastrocnemius spinal and supraspinal adaptations were assessed through the recording of H-reflexes and V-waves, with electrical stimulations of the posterior tibial nerve evoked at rest and during MVC, respectively. After one week, only the MI training group increased both plantar flexion MVC and RTD. The enhancement of muscle torque capacity was accompanied by significant increase of electromyographic activity and V-wave during MVC and of H-reflex at rest. The increased cortical descending neural drive and the excitability of spinal networks at rest could explain the greater RTD and MVC after one week of MI training.     

Discriminant analysis of anthropometric and biomotor variables among elite adolescent female athletes in four sports

The aim of this study was to identify anthropometric and biomotor variables that discriminated among groups of elite adolescent female athletes aged 14.3 +/- 1.3 years (mean +/- s) from four different sports (tennis, n = 15; swimming, n = 23; figure skating, n = 46; volleyball, n = 16). The anthropometric variables included body mass, height, bi-epicondylar breadth of the distal extremity of the humerus and femur, maximal girth of the calf and biceps and the sum of five adipose skinfolds. The biomotor variables were maximal aerobic power, muscular endurance and flexibility of the trunk. Discriminant analysis revealed three significant functions (P < 0. 05). The first discriminant function primarily represented differences between figure skaters and all other groups of athletes. The other two underlined anthropometric and biomotor differences between swimmers and volleyball players and between tennis players and swimmers, respectively. After validation, the analysis showed that 88% of the athletes were correctly classified in their respective sports. Our model confirms that elite adolescent female athletes show physical and biomotor differences that clearly distinguish them according to their particular sport.     

Education and Multimedia: the actions of the European Union

This paper sets out the findings and recommendations of a task force which was set up by the European Commission which investigated the “Educational Multimedia”. It illustrates some of the strategic planning which has taken place across EU member states to co‐ordinate work on new education technologies to enhance teaching and learning.     

Does company strategy have any lessons for educational planning?

former Member of the Administrative Board of the International Institute for Educational Planning (IIEP).Author of: Entreprise, marchés, étatand L'enseignement supérieur et l'idée d'université.     

A developmental study of school performance explanations of 6 to 11-year-olds: Causal differentiation and internality norm

Children's explanations of their performances are characterized by an increase of internal explanations over external ones. Originally considered a manifestation of cognitive development, this change has more recently been considered as an appropriation of a social norm. Two investigations are presented analyzing development of causal explanations of success and failure in mathematics and drawing. In the first study, two measures of causal attribution are compared in order to show that the use of unipolar scales is more suitable for illustrating differences in causal factors progressively operated by children. The hypothesis of the appropriation of a norm of internality is investigated in the second study. Results do not confirm this hypothesis and further, they cannot be interpreted solely in terms of cognitive development. They are discussed in the frame of a theory of socio-cognitive development.     

Physical activity awareness of European adolescents: The HELENA study

The aim of this study was to assess physical activity (PA) awareness of adolescents and to identify anthropometric and psychosocial factors that can lead to under or overestimation of PA. This study included 2044 adolescents. Participants wore a uniaxial accelerometer for 7 days to measure PA and completed a self-rated questionnaire about PA. Adolescents were classified into four PA awareness subgroups (realistically active, overestimators, underestimators and realistically inactive) according to the self-rated and objective assessment of PA. Characteristics and psychosocial factors of the self-rated physically active groups were compared using bivariate and multivariate mixed logistic regression models. Forty-five percent of adolescents reported their PA levels correctly (34.8% realistically active and 10.1% realistically inactive). Among the 59.4% who were objectively inactive, 82.9% tended to overestimate their PA level. Adolescents who overestimated their PA level were older (P < .05), had more support from mother and a best friend (P < .05) and had higher cardiorespiratory fitness (P < .001) compared with those who were realistically active. A significant number of adolescents believe that they are physically active when they are not. Improving awareness, especially in the high-risk groups identified here, might help to bring about behavioural changes in physically inactive adolescents.     

On the interest of enunciative postures (co-enunciation,under-enunciation,over-enunciation) for the interpretation of texts (in the classroom) / Sobre el interés de las posturas enunciativas de coenunciación,infraenunciación y supraenunciación para la interpretación de textos (en el aula)

Abstract

This article makes a provisional assessment of the question of enunciative postures. It begins by distinguishing co-enunciation and co-locution and defining postures with respect to the role of the enunciators in the co-construction of points of view (POV): co-enunciation corresponds to the speaker’s co-construction of a common POV, which commits them as enunciators. Over-enunciation is defined as an unequal co-construction of a dominating POV and under-enunciation consists of the unequal co-construction of a dominated POV. The second part illustrates the role of these different postures in the analysis and interpretation of texts with the aim of optimising their pedagogical exploitation by defining the enunciative stakes and the interactional positioning underlying in the construction of POV.