Considerations for protein intake in managing weight loss in athletes

Abstract

A large body of evidence now shows that higher protein intakes (2–3 times the protein Recommended Dietary Allowance (RDA) of 0.8 g/kg/d) during periods of energy restriction can enhance fat-free mass (FFM) preservation, particularly when combined with exercise. The mechanisms underpinning the FFM-sparing effect of higher protein diets remain to be fully elucidated but may relate to the maintenance of the anabolic sensitivity of skeletal muscle to protein ingestion. From a practical point of view, athletes aiming to reduce fat mass and preserve FFM should be advised to consume protein intakes in the range of ～1.8–2.7 g kg^?1 d^?1 (or ～2.3–3.1 g kg^?1 FFM) in combination with a moderate energy deficit (?500 kcal) and the performance of some form of resistance exercise. The target level of protein intake within this recommended range requires consideration of a number of case-specific factors including the athlete's body composition, habitual protein intake and broader nutrition goals. Athletes should focus on consuming high-quality protein sources, aiming to consume protein feedings evenly spaced throughout the day. Post-exercise consumption of 0.25–0.3 g protein meal^?1 from protein sources with high leucine content and rapid digestion kinetics (i.e. whey protein) is recommended to optimise exercise-induced muscle protein synthesis. When protein is consumed as part of a mixed macronutrient meal and/or before bed slightly higher protein doses may be optimal.     

Primary and secondary effects in the explanation of disadvantage in education: the children of immigrant families in France

This paper explores the prospective transition of immigrant and native students in France from lower to upper secondary school. Because they are more likely to be tracked to less prestigious (vocational) tracks, immigrant and immigrant‐origin students are significantly disadvantaged at this key academic stage in comparison with the children of native families. Primary and secondary sources of educational disadvantage are explored to explain this phenomenon. Primary effects appear to account for the entire initial disadvantage, while secondary effects could have a positive impact for immigrant‐origin students. Nonetheless, immigrant families appear to be more conservative than native families and may need stronger evidence that their children will succeed in upper secondary school.     

Minimal realizations and canonical forms for bilinear systems

The minimal realization theory for input–output maps that arise from finite- dimensional, continuous time, bilinear systems is discussed. It is shown that an observed bilinear system (i.e. a bilinear system together with an observation functional, but without a fixed initial state) is completely determined by its input–output correspondence, i.e. its multivalued input–output map. A precise formulation and proof of the result are given that continuous canonical forms for bilinear systems do not exist. This is done by adapting to the bilinear case an idea due to Hazewinkel and Kalman for the case of linear systems. In addition, the proof presented here has the advantage of not involving any algebraic geometry, which makes it considerably simpler than the original proof of the linear systems result.     

Participation in sports in childhood and adolescence and physical activity in adulthood: A systematic review

ABSTRACT

The aim of this study was to systematically review the literature to verify the association between participation in sports (PS) in childhood and adolescence and physical activity (PA) in adulthood. A systematic search was conducted in the following databases: Medline (PUBMED), Web of Science, Scopus, and SPORTDiscus, LILACS and SciELO. All steps of the process followed the recommendations of the PRISMA FlowDiagram. After all the steps of the process, 29 articles were included for analysis. In general, only three of the studies analyzed found no relation between PS in childhood and adolescence and PA in adulthood. However, a positive relationship was found to be weak in only 7% of the studies, a moderate relation in 62% of the studies, and a strong relation in 21%. It was found that higher weekly frequencies of PS; persistence of at least three years of PS and, finally, the highest level of practice and/or competition reached were related to higher levels of PA in adulthood. Thus, it can be concluded that there is a positive association considered moderate to strong between PS in childhood and adolescence and PA in adulthood.     

Variable training: effects on velocity and accuracy in the tennis serve

Abstract

Variable practice has been shown to be an effective strategy to improve open motor skills. However, the usefulness of this procedure in closed motor skills remains controversial. The following study has the objective of analysing the effects of variability practice in the improvement of a closed skill. The skill studied has been the tennis serve. Thirty young tennis players (13 ± 1.52 years), divided in two groups, took part in this study. One group practiced in variable conditions and the other group in consistency conditions. Both groups performed 12 training sessions (60 serves/session). The variable practice group improved their accuracy significantly compared with the consistency group (F_3.25 = 3.078; P = 0.035). The velocity of serve increased after training in both groups (F_3.25 = 15.890; P = 0.001). The practice in variable conditions seems to be effective in improving the performance of the tennis serve.     

Unconventional word segmentation in Brazilian children’s early text production

An important element of learning to read and write at school is the ability to define word boundaries. Defining word boundaries in text writing is not a straightforward task even for children who have mastered graphophonemic correspondences. In children’s writing, unconventional word segmentation has been observed across a range of languages and contexts with more occurrences of hyposegmentation (failure to separate two or more written words with a space) than hypersegmentation (written words are split into more than one segment). However, it is still unclear how frequent these errors are and the relationships of these written error patterns to the child’s development in oral language, spelling and reading remains relatively unexplored. To address these issues, unconventional written lexical segmentations in Brazilian Portuguese children’s text production during their first years at primary school (Year 1 to Year 3) were examined in relation to different cognitive and linguistic measures and patterns of spelling errors. Results reveal that in Portuguese the establishment of word boundaries in written text is not explained by visuospatial skills or limitations in processing resources (working memory). In contrast higher occurrences of hyposegmentation patterns were associated with lower levels of reading, vocabulary, verbal ability and morphological awareness whereas hypersegmentations were rarer and related to lower levels of reading and morphological awareness and typically only occurred in the initial stages of learning to write (Year 1). Occurrences of hyposegmentations as well as hypersegmentations were also related to spelling errors which reflected children’s poor phonological skills.     

An international comparison of community engagement in higher education

Community engagement in higher education is a shift beyond the traditional roles of instruction and research. This paper presents a transnational view of community engagement developed from two case studies of universities in the Philippines and Australia. The study, revealed variations in the way community engagement is understood and implemented by universities across different countries. These variations are related to economic, social-cultural, political and organizational factors. The role of university leadership was found to have a critical role in embedding community engagement in the organizational identity and image.