Accelerometer-assessed Physical Activity in Epidemiology: Are Monitors Equivalent?

PURPOSE: Accelerometers are increasingly being used to assess physical activity in large-scale surveys. Establishing whether key physical activity outcomes can be considered equivalent between three widely used accelerometer brands would be a significant step toward capitalizing on the increasing availability of accelerometry data for epidemiological research. METHODS: Twenty participants wore a GENEActiv, an Axivity AX3, and an ActiGraph GT9X on their nondominant wrist and were observed for 2 h in a simulated living space. Participants undertook a series of seated and upright light/active behaviors at their own pace. All accelerometer data were processed identically using open-source software (GGIR) to generate physical activity outcomes (including average dynamic acceleration (ACC) and time within intensity cut points). Data were analyzed using pairwise 95% equivalence tests (±10% equivalence zone), intraclass correlation coefficients (ICC) and limits of agreement. RESULTS: The GENEActiv and Axivity could be considered equivalent for ACC (ICC = 0.95, 95% confidence interval (CI), 0.87-0.98), but ACC measured by the ActiGraph was approximately 10% lower (GENEActiv/ActiGraph: ICC = 0.86; 95% CI, 0.56-0.95; Axivity/ActiGraph: ICC = 0.82; 95% CI, 0.50-0.94). For time spent within intensity cut points, all three accelerometers could be considered equivalent to each other for more than 85% of outcomes (ICC ≥0.69, lower 95% CI ≥0.36), with the GENEActiv and Axivity equivalent for 100% of outcomes (ICC ≥0.95, lower 95% CI ≥0.86). CONCLUSIONS: GENEActiv and Axivity data processed in GGIR are largely equivalent. If GENEActiv or Axivity is compared with the ActiGraph, time spent within intensity cut points has good agreement. These findings can be used to inform selection of appropriate outcomes if outputs from these accelerometer brands are compared.

Understanding the health of lorry drivers in context: A critical discourse analysis.

This article moves beyond previous attempts to understand health problems in the lives of professional lorry drivers by placing the study of drivers' health in a wider social and cultural context. A combination of methods including focus groups, interviews and observations were used to collect data from a group of 24 lorry drivers working at a large transport company in the United Kingdom. Employing a critical discourse analysis, we identified the dominant discourses and subject positions shaping the formation of drivers' health and lifestyle choices. This analysis was systematically combined with an exploration of the gendered ways in which an almost exclusively male workforce talked about health. Findings revealed that drivers were constituted within a neoliberal economic discourse, which is reflective of the broader social structure, and which partly restricted drivers' opportunities for healthy living. Concurrently, drivers adopted the subject position of 'average man' as a way of defending their personal and masculine status in regards to health and to justify jettisoning approaches to healthy living that were deemed too extreme or irrational in the face of the constraints of their working lives. Suggestions for driver health promotion include refocusing on the social and cultural - rather than individual - underpinnings of driver health issues and a move away from moralistic approaches to health promotion.

Standing Classrooms: Research and Lessons Learned from Around the World.

Children spend between 50 and 70 % of their time sitting while at school. Independent of physical activity levels, prolonged sitting is associated with poor health outcomes in adulthood. While there is mixed evidence of health associations among children and adolescents, public health guidelines in the USA, UK, Australia and Canada now recommend young people should break up long periods of sitting as frequently as possible. A potentially effective approach for reducing and breaking up sitting throughout the day is changing the classroom environment. This paper presents an overview of a relatively new area of research designed to reduce youth sitting time while at school by changing the classroom environment (n = 13 studies). Environmental changes included placement of height-adjustable or stand-biased standing desks/workstations with stools, chairs, exercise balls, bean bags or mats in the classroom. These 13 published studies suggest that irrespective of the approach, youth sitting time was reduced by between ~44 and 60 min/day and standing time was increased by between 18 and 55 min/day during classroom time at school. Other benefits include increased energy expenditure and the potential for improved management of students' behaviour in the classroom. However, few large trials have been conducted, and there remains little evidence regarding the impact on children's learning and academic achievement. Nevertheless, with an increasing demand placed on schools and teachers regarding students' learning outcomes, strategies that integrate moving throughout the school day and that potentially enhance the learning experience and future health outcomes for young people warrant further exploration.