Differences in activation patterns between eccentric and concentric quadriceps contractions.

Previous studies analysing electromyograms (EMGs) from indwelling electrodes have indicated that fast-twitch motor units are selectively recruited for low-intensity eccentric contractions. The aim of this study was to compare the frequency content of surface EMGs from quadriceps muscles during eccentric and concentric contractions at various contraction intensities. Electromyograms were recorded from the rectus femoris, vastus lateralis and vastus medialis muscles of 10 men during isokinetic (1.05 rad x s(-1)) eccentric and concentric knee extension contractions at 25%, 50%, 75% and 100% of maximal voluntary contraction (MVC) for each contraction mode. Additionally, isometric contractions (70 degrees) were performed at each intensity. The mean frequency and root mean square (RMS) of the surface EMG were computed. Mean frequency was higher for eccentric than concentric contractions at 25% (P < 0.01), 50% (P < 0.01) and 75% (P < 0.05) but not at 100% MVC. It increased with increasing contraction intensity for isometric (P < 0.001) and concentric (P < 0.01) contractions but not for eccentric contractions (P = 0.27). The EMG amplitude (RMS) increased with increasing contraction intensity similarly in each contraction mode (P < 0.0001). Higher mean frequencies for eccentric than concentric contractions at submaximal contraction intensities is consistent with more fast-twitch motor units being active during eccentric contractions.     

All I really needed to know I learned during gastrulation

Note from the Editor     

Using Activity Theory to inform sessional teacher development: what lessons can be learned from tutor training models?

Abstract

Sessional teachers in universities are often marginalised by their part-time status, availability for training, and invisibility within the institution’s infrastructure. Nevertheless, tutors as a subset of this group, regularly have access to some training and development. This paper presents a methodological approach for implementing the BLASST framework for sessional staff at a New Zealand university, based on a project to benchmark support for tutors. Using Activity Theory, I discuss tensions associated with developing a training programme for tutors and how such an approach can aid the development of similar models for all sessional teachers.     

Enigmas in School Science: students’ conceptions for scientifically associated words

Master's students were involved in the design, and later the administration, of a questionnaire for 500 junior secondary students in Botswana and Lesotho, to buildup a picture of student perceptions of science and technology. Responses to mainly open‐ended questions were categorised according to key phrases mentioned by the students. There was some confusion over the differences between science and technology, but they were overwhelmingly perceived as subjects appropriate to both sexes. Science and technology were seen in broad socio‐economic terms, enabling people to cope in the modern world, gain employment in both the formal and informal sectors, and contribute towards national development. Although science and technology were judged to have enhanced the quality of life, they had introduced conflicts into traditional beliefs and cultures, in part as a result of increasing female emancipation. The attitudes of the students towards the two subjects, and to the impact they have had on everyday life, were congruent with the philosophical aims of the science and technology syllabuses of both countries and with global initiatives such as Project 2000 +.     

Roger Osborne (1940–1985), University of Waikato, New Zealand

This short paper outlines the emergence and achievements of the Science Education Research Unit at the University of Waikato over the period 1979–1985 under the leadership of the late Dr. Roger Osborne. Following his attendance at the ASERA meeting in Wagga Wagga in 1977, Roger Osborne rapidly built up a very productive team, which he led until his death in 1985. His legacy is tentatively evaluated. In conclusion, the cultural context in which this work took place is sketched.