Changes in swimming technique during time to exhaustion at freely chosen and controlled stroke rates

Abstract

The aim of this study was to assess technical changes during constrained swimming in time-to-exhaustion tests. Ten swimmers of national standard performed a maximal 400-m front crawl and two sets of exhaustion tests at 95%, 100%, and 110% of mean 400-m speed. In the first set (free), swimmers had to maintain their speeds until exhaustion and mean stroke rate was recorded for each test. In the second set (controlled), the same speed and individual corresponding stroke rate were imposed. The durations of the exhaustion tests, relative durations of the stroke phases, and arm coordination were analysed. For each speed in the “controlled” set, the exhaustion tests were shorter. Moreover, variables were consistent, suggesting a stabilization of stroke technique. Under the free condition, stroke rate increased to compensate for the decrease in stroke length. At the same time, swimmers reduced the relative duration of their non-propulsive phases in favour of the propulsive phases. Thus, swimmers changed their arm coordination, which came close to an opposition mode. These two constraints enable swimmers both to maintain their stroking characteristics and develop compensatory mechanisms to maintain speed. Moreover, stroke rate can be seen as a useful tool for controlling arm technique during paced exercise.     

Kinesthetic Perception of the Vertical as a Function of Sport Experience

Abstract

Near-infrared spectroscopy is currently used to assess changes in the oxygen saturation of the muscle during exercise. The primary purpose of this study was to assess the reliability of near-infrared spectroscopy in determining muscle oxygen saturation (StO₂) in the vastus lateralis during cycling and the gastrocnemius during running for exercise intensities at lactate threshold and maximal effort. Test-retest reliability was determined from an intraclass correlation coefficient obtained from a one-way analysis of variance. Reliability of muscle StO₂ for the gastrocnemius at lactate threshold was R = .87, and R= .88 at maximal effort. Reliability of muscle StO₂ for the vastus lateralis at lactate threshold was R= .94 and R = .99 at maximal effort.     

Toddlers Use the Number Feature in Determiners During Online Noun Comprehension

Function words support many aspects of language acquisition. This study investigated whether toddlers understand the number feature of determiners and use it for noun comprehension. French offers an ideal “test case” as number is phonetically marked in determiners but not in nouns. Twenty French‐learning 24‐month‐olds completed a split‐screen experiment. Looking times to target pictures were measured under 3 trial types varying in the degree to which the determiner matched the number displayed in the object(s). Children looked longer when the determiner matched the object(s), and were confused in trials of clear mismatch. Importantly, their processing resembled that of French adults ( D. Dahan, D. Swingley, M. K. Tanenhaus, & J. S. Magnuson, 2000 ). Thus, children understand the determiner number feature early in acquisition and use this knowledge to constrain online comprehension.     

REACTION TIME AND INTELLIGENCE

The limited capacity theory is often cited to account for negative correlations between choice reaction time and different IQ measures. It is claimed, since working memory has strictly limited capacity to process a great amount of vital information and STM information decays if not rehearsed, that speed is an indispensable condition of efficient dealing with cognitive tasks. It ensures good performance before important information is forgotten. In the present experiment a special kind of task was applied‐one which supposedly puts a substantial load on the system of working memory. It was hypothesized that subjects dealing well with this task would also obtain high scores on general ability tests. The data obtained from 48 psychology students in the self‐paced, computer assisted study did not confirm this hypothesis. The data are interpreted as posing a challenge for the limited capacity theory, which must either be reformulated or replaced by better elaborated theoretical constructions.

     

Principled Teaching for Deep Progress: Improving Mathematical Learning Beyond Methods and Materials

This paper contributes to knowledge about principled action which makes a difference to learners attainment. We report on the Improving Attainment in Mathematics Project,¹ a project focusing on low-attaining secondary students. The purpose of the project was to introduce innovations in practice through action research with 10 teachers over 2 years, and evaluate the effect on students learning using national test scores, teachers reports, non-routine tasks and other performance indicators. However, this is not a study which shows how certain methods lead to better results. While it was found that learning improved, the methods and strategies the teachers used were not always generalisable across the project, indeed some were contradictory. Continued searching led to the identification of common underlying principles of teaching which different teachers manifested in different ways. Overt methods were less important than the collection of beliefs and commitments which underpinned teachers choices. There was, however, a convergence of practice around a focus on long-term development, the process of becoming a learner of mathematics, rather than short-term gains. In addition, we had to deal with some of the realities of authentic collaborative research with practitioners.     

Prospective teachers navigating intersecting communities of practice: early school placement

An issue of particular concern in mathematics teacher education is the relationship between theory and practice, and the nature of university–school partnerships. We report here on results from a research project answering the call for a more systematic understanding of the practice learning context. The study focuses on the new Norwegian elementary teacher education programme and highlights the difficulties involved in connecting theory and practice and how prospective teachers may be supported in this respect. Focus group interviews involving 51 first-year prospective teachers and 25 teacher–mentors investigated early school placements, specifically prospective teachers’ positions in the classroom as teachers of mathematics, and the ways in which the mentoring relationship supported their developing role. Taking a communities of practice perspective, we found that the idea of movement across intersecting and sometimes conflicting communities of practice is helpful in aiding our understanding of the difficulty of connecting theory and practice. Additionally, variations in mentoring styles and perceptions of prospective teachers’ mathematics and pedagogic knowledge competencies play a part in some prospective teachers’ difficulties in taking up a role as legitimate peripheral participant in the school. We conclude by considering ways in which prospective teachers might be better supported to cope with school placement.     

Splitting Clips and Telling Tales: Students Interactions with Digital Video

This paper reports on an experimental project in digital video editing with 10 year olds in the UK which explored their interactions with creative digital technologies. Data on the pupil’s interactions with the software was gathered on video and analysed. A theoretical framework drawn from second generation activity theory was applied and tensions resulting from mismatches between pupil’s approaches to the task and the ways the task were framed are reported on. The paper argues that pupils exhibit a number of behaviour based roles in relation to the technology dependent on compliance with the instructions of the teachers, creativity and their desire to explore the affordances of the technology. The paper concludes by asking questions about how new forms of cultural production such as digital video work can be incorporated authentically into school settings, and how a pedagogy to support learning with new types of technology can be developed by drawing on insights provided by socio-cultural approaches to understanding technology use in human activity systems.