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.     

Can Pre-entry Characteristics Account for the Ethnic Attainment Gap? An Analysis of a Flemish University

Research in Higher Education - Discussions about social justice imply discussions about higher education. After all, a whole set of literature has illustrated how ethnic minority students face all...     

Tradutore,traditore: Can the aect code of ethics “speak” across cultures?

Conclusion Although many questions remain unanswered, these early translations of the AECT Code of Ethics will be available at the AECT Web site to ensure that access to the principles is offered in languages other than English. As they become available, more translations will be added to the English, Farsi, French, Mandarin Chinese, Portuguese, and Spanish versions. The translations will be saved as PDF files to retain the unique characters of each language. Additional translators with expertise in both educational technology and the targeted languages will be identified. Exploration of ways to encourage debate regarding the viability of the translations within diverse cultures continues. The ultimate hope is that collaboration among members of the professional ethics committee of AECT, the translators, and interested educators will result in the development of a Code of Ethics that “speaks” across cultures and establishes a meaningful guide to professional conduct around the world. Authors’ Note: This article expands on earlier work published in the (2002) Proceedings of the Annual Meeting of the Association for Educational Communications and Technology, edited by M, Simonson.     

Instruction in basic concepts and first-grade achievement

First-grade students were administered the Boehm Test of Basic Concepts (BTBC), then given 15 weeks of instruction relevant to the concepts for which corresponding BTBC items were most frequently missed. Improvements in mid-year and end-of-year BTBC performance did not occur as a function of instruction, but a significant treatment effect did occur on a transfer measure, the Stanford Achievement Test. Results are discussed in terms of the sensitivity of the BTBC, possible nonlinguistic effects of the instructional program, and the practical significance of the treatment effect.