Visual function,performance, and processing of basketball players vs. sedentary individuals

BackgroundAthletes tend to have better visuo-motor performance than do sedentary individuals. However, several basic visual-function and perceptual parameters remain unexplored to date. In this study, we investigated whether differences exist in visual function, performance, and processing between basketball players and individuals without a sport-involvement background.MethodsA total of 33 healthy men with no visual impairment or pathology were divided into 2 groups, depending on the involvement in sport (semi-professional basketball players and sedentary individuals). We tested their baseline heart-rate variability in the resting position apart from subjective questionnaires to determine their physical fitness level, and we checked their visual function, performance, and processing through an extended battery of optometric tests.ResultsThe 2 groups differed in resting heart-rate variability parameters (p < 0.001), confirming their dissimilarities in regular time practising sports per week. The basketball players showed a closer breakpoint and recovery nearpoint of convergence, a higher fusional-vergence rate, better discriminability halos, and better eye–hand coordination (all p values < 0.05).ConclusionThese results show evidence that athletes, basketball players in this case, exhibit better performance in several visual abilities in comparison to a group of individuals without sporting backgrounds, suggesting an improvement due to the systematic involvement of those skills during basketball practice.     

Acute intraocular pressure changes during isometric exercise and recovery: The influence of exercise type and intensity,and participant´s sex

ABSTRACT

We assessed the intraocular pressure (IOP) behaviour during a 1-minute period of isometric physical effort and the immediate 1-minute of recovery in the mid-thigh clean pull and squat exercises at three different intensities. Twenty physically active individuals performed the isometric mid-thigh clean pull and squat exercises at three intensities (0% [low-intensity], 25% [medium-intensity] and 50% [high-intensity] of the maximum isometric force). IOP was semi-continuously measured by rebound tonometry. There was a statistically significant effect of exercise intensity on IOP (p < 0.001, ?_p² = 0.416), observing that IOP increments were positively associated with exercise intensity. The mid-thigh clean pull and squat exercises did not demonstrate differences (p = 0.510), and also, no differences were observed between men and women (p = 0.683). The IOP changes during the isometric physical effort showed a positive linear behaviour in all conditions (r = 0.70 to 0.96). IOP returned to baseline levels after 8 seconds of recovery. Our data showed a progressive and instantaneous IOP increment during isometric exercise, which was positively associated with exercise intensity. IOP changes were independent on the type of exercise and participant´s sex. After exercise, IOP rapidly (≈ 8 seconds) returned to baseline levels.     

Is passive drag dependent on the interaction of kayak design and paddler weight in flat-water kayaking?

Abstract

Drag is one of the major factors that influences kayaking performance. To focus on the drag of the kayak’s hull shape and the paddlers’ weight per se, the passive drag (D_p) was measured on a flat-water sprint course for one paddler with added weights. D_p was measured by an electromechanical towing device using a load cell, at incremental and constant velocities from 2.78 to 5.56 m/s. Three kayaks of different sizes and shapes (Nelo® K1 Quattro-M, ML, and L) were used and the paddlers’ body weight was adjusted with weights so the total paddler weight in the kayak was 65, 75, and 85 kg. The mean D_p increased by the power function of D = kvⁿ (mean R² = .990; SD .006). The D_p went from 21.37?±?1.29 N at 2.78 m/s to 89.32?±?6.43 N at 5.56 m/s. For the two lighter weighted kayaks (65 and 75 kg), the lowest D_p was observed with different kayak sizes (M, ML, or L) depending on the target velocity. The manufacturers suggest that paddlers should select a kayak size according to their body weight to minimise drag; however, the results of this study suggest that target velocities, and thus competition distance should also be factored into kayak selection.     

Children’s Models about Colours in Nahuatl-Speaking Communities

This paper presents the development and structure of indigenous children’s ideas about mixing colours as well as their ideas about each colour, derived from their traditions. The children were interviewed both at school and outside it, and an educational proposal was implemented. Ideas expressed in the school context were analysed using the partial possible model, which states that the inferences and explanations used to describe a subject consist of constricting ideas, rules of correspondence, and a set of phenomenological inferences about processes. After identifying these components in the children’s ideas, we developed models to describe their conceptions about mixing colours. We employed a different approach to analyse children’s ideas related to their cultural context. The results showed that children change from a conception that focuses on colours as entities that do not change and as properties of objects (model 1) to the idea that colour represents a quality of substances or objects that can be modified by mixing colours (model 2). Cultural context analysis showed that stories are independent from one another and that they are not connected to colour mixing processes, only to the actions of colour on people. We concluded that students generate independent constructions between school and cultural knowledge.     

Historians, archivists, and social activism: benefits and costs

This article explores how activism by historians and archivists relates to and affects their work and how their work affects their activism. The findings are based on a survey of 195 historians (including educators) and archivists who self-identified as “someone who takes part in activities that are intended to achieve social or political change, especially someone who is a member of an organization.” The respondents participate in a wide variety of causes. Typically, their activities as activists reflect their professional skills and concerns, with a large majority involved in collecting and preserving the records of activist organizations. The article examines the benefits and costs for employers of employee activism, concluding the benefits outweigh the costs. The article also examines how activism affects the relationship between employers and their activist employees. While many activists receive recognition and other benefits from their employers for their activism, a minority suffers negative consequences up to and including firing and a substantial number feel inhibited from activism by their employers. The article also explores the effects of activism for the different occupational groups, determining that they are relatively similar but with some differences.     

Planning as action research

Planning contains so much more than the written plan. Early in 2000, an invitation came from the Collaborative Action Research Network (CARN), to people experienced in action research who might want to help plan and present an action research event for elementary school science teachers in Venezuela, South America, in Autumn 2000. This article analyses the outcomes from planning and enacting the resulting workshop to show how planning can be the subject of action research. It goes on to show how planning and teaching interact in a multifaceted way towards technical, practical and emancipatory ends. Planning and teaching are best seen as conversation, a conversation that is both synchronous and asynchronous.     

Emotion,understanding, and social skills among boys at risk of attention deficit hyperactivity disorder

There is growing interest in the role of emotional competence in middle school children's adjustment and functioning, yet many populations remain underresearched. Few studies have explored the emotional competence, especially emotion understanding, of children with, or at risk of, attention deficit hyperactivity disorder (ADHD), and even fewer have examined the role emotion understanding plays in these children's social skills. Our study investigates a profile of the emotion understanding capacities of Israeli boys at risk of ADHD and evaluates its association with their social skills. One hundred and fifty‐two boys (grades 4–6) were each assigned to an at‐risk (n = 66) or comparison (n = 86) group based on their scores on an ADHD symptoms questionnaire (Conners Rating System–Revised). The two groups were matched on age, socioeconomic status and class, and school environment. Group comparisons revealed that relative to their non–at‐risk counterparts, at‐risk boys demonstrated less mature emotion understanding. Finally, our findings indicate that poor emotion understanding plays a more notable role in the social functioning of at‐risk than non–at‐risk children. This study's contribution to the understanding and school treatment of children with ADHD emotional and social competencies is discussed. © 2009 Wiley Periodicals, Inc.