The long-term athlete development model: physiological evidence and application

Within the UK, the "Long Term Athlete Development" (LTAD) model has been proposed by a variety of national governing bodies to offer a first step to considering the approach to talent development. The model, which is primarily a physiological perspective, presents an advancement of understanding of developing athletic potential alongside biological growth. It focuses on training to optimize performance longitudinally, and considers sensitive developmental periods known as "windows of opportunity". However, it appears that there are a number of problems with this theoretical model that are not necessarily transparent to coaches. Principally, the model is only one-dimensional, there is a lack of empirical evidence upon which the model is based, and interpretations of the model are restricted because the data on which it is based rely on questionable assumptions and erroneous methodologies. Fundamentally, this is a generic model rather than an individualized plan for athletes. It is crucial that the LTAD model is seen as a "work in progress" and the challenge, particularly for paediatric exercise scientists, is to question, test, and revise the model. It is unlikely that this can be accomplished using classical experimental research methodology but this should not deter practitioners from acquiring valid and reliable evidence.     

学生合约与学生消费者：学习的市场化与高等教育公共产品性质的侵蚀

自20世纪80年代中期以来,全世界范围内接连出现的政府主导的改革将高等教育系统向"教科书般"经济市场越推越近已实施的改革包括公司化、引入竞争性资助、增加学费和其他费用、使用高校管理中产出模式和绩效报告。但是,没有一个国家面向本国学生的第一学位教育是按照真正的资本主义经济市场来运作的,没有研究型大学的发展是被股东、利润、市场份额、配置效率或商品形式所驱动的。在一些国家,只有职业培训和国际教育才会真正收取商业性质的学费。虽然高等教育中普遍存在激烈的竞争、企业家精神和消费者话语,但资本主义在其中没有一席之地;现有的高等教育市场充其量是一个受监管的准市场在许多国家,高等教育领域的"市场改革"不同于交通、通信、广播电视和医疗保险界的私有化和商业化。究其原因,本文发现真正的市场改革受制于高等教育领域特定的内在限度(公共产品、地位竞争)以及与这些限度相关的政治因素、高等教育市场改革计划在本质上是乌托邦式的,目前市场改革的抽象理想仍在持续并不是因为它具有真正实现的前景,而是由于外源性政策的推动(如财政缩减、政府控制等)。如果资本主义市场是无法实现的,为什么要继续假装它们可以实现呢?我们需要一个与教育系... 更多还原     

Experimental Evaluation of the Value Added by Raising a Reader and Supplemental Parent Training in Shared Reading

Research Findings: In an effort toward developing a comprehensive, effective, scalable, and sustainable early childhood education program for at-risk populations, we conducted an experimental evaluation of the value added by 2 family involvement programs to the Texas Early Education Model (TEEM). A total of 91 preschool classrooms that served minority populations of low socioeconomic status were randomly assigned to TEEM, TEEM plus Raising a Reader (RAR), or TEEM plus RAR augmented by Family Nights. Assessments of oral language and print knowledge were completed by more than 500 children at the beginning and end of the school year. Multilevel analyses of covariance controlled for classroom nesting and individual differences in age, ethnicity, and pretest scores. Although RAR alone demonstrated no added value, augmentation of RAR with Family Nights demonstrated significant impacts on measures of oral language (ts = 1.81–2.51, .05 < ps < .01) and print knowledge (t = 2.39, p < .01). Practice or Policy: Thus, parent training in shared reading practices appears to be necessary for children to benefit from programs that enrich the home literacy environment. That the combined program particularly benefited children who started preschool lagging behind in school readiness (ts = 1.64–2.49, ps < .05) suggests that this comprehensive model offers hope for closing the achievement gap.     

Beyond Punnett Squares: Student Word Association and Explanations of Phenotypic Variation through an Integrative Quantitative Genetics Unit Investigating Anthocyanin Inheritance and Expression in Brassica rapa Fast Plants

Genetics instruction in introductory biology is often confined to Mendelian genetics and avoids the complexities of variation in quantitative traits. Given the driving question “What determines variation in phenotype (Pv)? (Pv=Genotypic variation Gv + environmental variation Ev),” we developed a 4-wk unit for an inquiry-based laboratory course focused on the inheritance and expression of a quantitative trait in varying environments. We utilized Brassica rapa Fast Plants as a model organism to study variation in the phenotype anthocyanin pigment intensity. As an initial curriculum assessment, we used free word association to examine students’ cognitive structures before and after the unit and explanations in students’ final research posters with particular focus on variation (Pv = Gv + Ev). Comparison of pre- and postunit word frequency revealed a shift in words and a pattern of co-occurring concepts indicative of change in cognitive structure, with particular focus on “variation” as a proposed threshold concept and primary goal for students’ explanations. Given review of 53 posters, we found ∼50% of students capable of intermediate to high-level explanations combining both Gv and Ev influence on expression of anthocyanin intensity (Pv). While far from “plug and play,” this conceptually rich, inquiry-based unit holds promise for effective integration of quantitative and Mendelian genetics.     

Influence of single-leg training on muscle metabolism and endurance during exercise with the trained limb and the untrained limb

We have previously shown that single-leg training results in improved endurance for exercise with the untrained leg (UTL) as well as for exercise with the trained leg (TL). The purpose of this study was to see whether the improved endurance of the untrained leg could be explained on the basis of changes in muscle metabolism. Exercise time to exhaustion at 80% of maximum oxygen uptake (VO2 max) was determined for each leg separately, pre- and post-training. Muscle metabolite concentrations were measured pre- and post-training in biopsy samples obtained immediately before this endurance test and at the pre-training point of exhaustion (END1). After six weeks of single-leg training endurance time was increased for both the UTL and the TL (UTL 34.0 +/- 16.4 min vs 97.9 +/- 26.3 min, P less than 0.01; TL 28.3 +/- 10.1 min vs 169.0 +/- 32.6 min, P less than 0.01). No changes in muscle metabolite concentrations were found in resting muscle. Training increased muscle ATP (P less than 0.05) and glycogen (P less than 0.01) concentrations and decreased muscle lactate concentration (P less than 0.05) in the TL at END1. No significant changes in muscle metabolite concentrations were found for the UTL. The improved endurance of the contralateral limb after single-leg training could not be explained on the basis of changes in muscle metabolism.