Adolescent physical activity levels: discrepancies with accelerometer data analysis

This study investigated the effects of epoch length and cut point selection on adolescent physical activity intensity quantification using vertical axis and vector magnitude (VM) measurement with the ActiGraph GT3X+ accelerometer. Four hundred and nine adolescents (211 males; 198 females) aged 12–16 years of age wore accelerometers during waking hours. The GT3X+ acceleration counts were reintegrated into 1, 5, 15, 30 and 60 s epoch lengths for both vertical axis and VM counts. One cut point was applied to vertical axis counts and three different cut points were applied to VM counts for each epoch length. Significant differences (P < 0.01) in mean total counts per day were observed between vertical axis and VM counts, and between epoch lengths for VM only. Differences in physical activity levels were observed between vertical and VM cut points, and between epoch lengths across all activity intensities. Our findings illustrate the magnitude of differences in physical activity outcomes that occur between axis measurement, cut points and epoch length. The magnitude of difference across epoch length must be considered in the interpretation of accelerometer data and seen as a confounding variable when comparing physical activity levels between studies.     

Research,Development and Tacit Capability in the Education System

The relevance gap between educational practice and research is often seen as a methodological problem. But communicative and social issues are also vitally important. The idea of tacit capability, from recent work in economics on research and development, characterises the knowledge which can be acquired by and attributed to an organisation as a conversational whole. (Schön's idea of reflective practice is unhelpfully monological.) I interpret and validate this idea in the light of Habermas’ account of communicative action. I use it to explore social problems in the relation between educational practice and research and suggest solutions modelled on enlightened industrial practice in Europe.     

Creating a model to examine motivation for sustained engagement in online communities

This paper considers factors that influenced long-term engagement in an online community. It draws on a case study of a 6 year online collaboration amongst a group of European teachers. The email interchange between these teachers was, with their agreement, saved and used as research data; intensive group interviews were also conducted, involving all the participants in the online group. Dynamic motivation models and Csikszentmihalyi’s concept of motivational flow were used to create a theoretical framework to analyse the email interchanges and group interview data so as to build an understanding of the teachers’ commitment to the online community. As a result of the analysis, the existing theoretical models were modified to produce a new combined model. This incorporates ideas grounded in the participants’ reasons for their sustained engagement in the collaboration. This combined model could provide a basis for planning future virtual interactions and for assessing their sustainability.