Pedometer reliability, validity and daily activity targets among 10- to 15-year-old boys

The aims of this study were to: (1) determine whether the number of pedometer counts recorded by adolescents differs according to the adiposity of the participant or location on the body; (2) assess the accuracy and reliability of pedometers during field activity; and (3) set adolescent pedometer-based physical activity targets. Seventy-eight 11- to 15-year-old Boy Scouts completed three types of activity: walking, fast walking and running. Each type was performed twice. Participants wore three pedometers and one activity monitor during all activities. Participants were divided into groups of normal weight (BMI < 85th percentile) and at risk of being overweight (BMI > or = 85th percentile). Intra-class correlations across the three activities indicated reliability (r = 0.51 - 0.92, P < 0.001). This conclusion was supported by narrow limits of agreement that were within a pre-set range that was practically meaningful. Multivariate analysis of covariance indicated adiposity group differences, but this difference was a function of the increased stature among the larger participants (P < 0.001). Ordinary least-squares regression models and multi-level regression models showed positive associations between the number of pedometer and activity monitor counts recorded by the three groups of participants during all activities (all P < 0.001). The mean number of counts recorded for all participants during the fast walk was 127 counts per minute. In conclusion, the pedometers provided an accurate assessment of adolescent physical activity, and a conservative estimate of 8000 pedometer counts in 60 min is equivalent to 60 min of moderate to vigorous physical activity.     

Academic Self-Concept: Modeling and Measuring for Science

In this study, the author developed a model to describe academic self-concept (ASC) in science and validated an instrument for its measurement. Unlike previous models of science ASC, which envisage science as a homogenous single global construct, this model took a multidimensional view by conceiving science self-concept as possessing distinctive facets including conceptual and procedural elements. In the first part of the study, data were collected from 1,483 students attending eight secondary schools in England, through the use of a newly devised Secondary Self-Concept Science Instrument, and structural equation modeling was employed to test and validate a model. In the second part of the study, the data were analysed within the new self-concept framework to examine learners’ ASC profiles across the domains of science, with particular attention paid to age- and gender-related differences. The study found that the proposed science self-concept model exhibited robust measures of fit and construct validity, which were shown to be invariant across gender and age subgroups. The self-concept profiles were heterogeneous in nature with the component relating to self-concept in physics, being surprisingly positive in comparison to other aspects of science. This outcome is in stark contrast to data reported elsewhere and raises important issues about the nature of young learners’ self-conceptions about science. The paper concludes with an analysis of the potential utility of the self-concept measurement instrument as a pedagogical device for science educators and learners of science.