How does mental fatigue affect soccer performance during small-sided games? A cognitive,tactical and physical approach

ABSTRACT

Objectives

We examine how mental fatigue (MF) influences peripheral perception, tactical behaviour, and physical performance of soccer players during a standardized small-sided game.     

Concurrent and longitudinal neuropsychological contributors to written language expression in first and second grade students

The primary purpose of this study was to examine several key questions related to the neuropsychological contributors to early written language. First, can we develop an empirical measurement model that encompasses many of the neuropsychological components that have been deemed as important to the development of written language? Second, once derived, will the neuropsychological components of this model remain stable over first and second grades or will the model change in its composition? Third, will the strength of the relationships between neuropsychological components and writing outcomes be constant over time, or will the strength of the relationships change over time? Finally, will the derived empirical model show significant concurrent and predictive relationships with written expression? The sample included 205 first grade students recruited from a single school district who were followed into the second grade via two cohorts: Measures were aligned with major neuropsychological components as extracted from theoretical models of written expression and available empirical findings examining the neuropsychological contributors to writing in children. These domains included fine-motor speed, language, short-term memory, long-term memory, and various attention/executive functions including working memory. Confirmatory factor analyses (CFAs) and longitudinal structural equation modeling (SEM) methods documented that three core latent traits were present and stable at both grades 1 and 2: Fine-Motor, Language, and Attention/Executive Functions. The overall model was highly related to written expression and spelling at both grades 1 and 2, with the first grade latent traits accounting for 52 and 55% of the variance in second grade written expression and spelling, respectively. At both grades, the Language and Attention/Executive Functions latent traits were more highly associated with written expression and spelling than the Fine-Motor latent trait.     

Multidimensional relevance: Prioritized aggregation in a personalized Information Retrieval setting

A new model for aggregating multiple criteria evaluations for relevance assessment is proposed. An Information Retrieval context is considered, where relevance is modeled as a multidimensional property of documents. The usefulness and effectiveness of such a model are demonstrated by means of a case study on personalized Information Retrieval with multi-criteria relevance. The following criteria are considered to estimate document relevance: aboutness, coverage, appropriateness, and reliability.     

Going virtual and going wide: comparing Team-Based Learning in-class versus online and across disciplines

Education and Information Technologies - Team-based learning (TBL) is an active learning pedagogy developed for in-class sessions and based on the collaborative work of small groups of students....     

A Review of the Brazilian Book Market

Brazil is a huge country with at least 100 million readers with a total population of 200 million. Is this a good number for you? The article describes the developments of the Brazilian book market and publishing industry. Sales in 2009 were an estimated $2.5 billion for more than 228 million copies of books sold. But a country this big, as it is almost 50% of entire South America, confronts several major challenges including a real lack of bookstores. But one of the channels that is growing every year are the door-to-door sales, it has grown from 5% of all sales in 2006 to 17% in 2009. In a country this big, the digital or eBooks may also be a very good strategy to get to more readers, but it is still a small market in Brazil. The interesting news is that publishers are working on it and looking for solutions and ways to act on this new area of digital and online publishing.     

The geometric curvature of the spine during the sirshasana,the yoga’s headstand

This study analysed the behaviour of the geometric curvature of the spine during sirshasana. The position of dorsal retroreflective markers was computed via stereophotogrammetric analysis in six males and five females (29.4 ± 8.8 years, 63.0 ± 11.4 kg, 1.66 ± 0.08 m [average ± standard deviation]). The spinal points were projected onto the sagittal and frontal planes of the trunk, a polynomial was fitted to the data and the two-dimensional geometric curvature was quantified. The inferior lumbar lordosis decreased compared to the orthostatic position and gait, which may favour the posterior protrusion of the lumbar spinal nucleus pulposus in people with posterior herniation. The lateral deviation at the middle of the thoracic spine increases during sirshasana, which may reflect increased difficulties for postural control and spinal loads. It could be useful for promoting positive spinal structural and functional chronic adaptations for healthy participants, if the yoga programme is carefully planned and the spinal alignment is carefully monitored during a headstand. However, it may aggravate some spinal diseases, especially scoliosis.     

Effects of caffeine chewing gum on race performance and physiology in male and female cyclists

This investigation reports the effects of chewing caffeinated gum on race performance with trained cyclists. Twenty competitive cyclists completed two 30-km time trials that included a maximal effort 0.2-km sprint each 10-km. Caffeine (~3–4 mg · kg^?1) or placebo was administered double-blind via chewing gum at the 10-km point following completion of the first sprint. Measures of power output, oxygen uptake, heart rate, lactate and perceived exertion were taken at set intervals during the time trial. Results indicated no substantial differences in any measured variables between caffeine and placebo conditions during the first 20-km of the time trial. Caffeine gum did however lead to substantial enhancements (mean ± 90% confidence limits (CLs)) in mean power during the final 10-km (3.8% ± 2.3%), and sprint power at 30-km (4.0% ± 3.6%). The increases in performance over the final 10-km were associated with small increases in heart rate and blood lactate (effect size of 0.24 and 0.28, respectively). There were large inter-individual variations in the response to caffeine, and apparent gender related differences in sprint performance. Chewing caffeine gum improves mean and sprint performance power in the final 10-km of a 30-km time trial in male and female cyclists most likely through an increase in nervous system activation.