The primary aim of this study is to examine the effectiveness of incorporating manually adjustable sit-stand desks in the classroom environment of 9-10 year olds in reducing sedentary behaviour at school during a full school year. Secondary aims include evaluating the effects of the intervention on health and learning outcomes as well as comparing the impact of full classroom allocation of sit-stand desks to a classroom of partial sit-stand desk allocation.

Rates of overweight and obesity and related chronic disease risk factors in children have increased worldwide over the past decades. Whilst it is widely acknowledged that regular physical activity provides health benefits, prolonged sedentary behaviour (sitting or reclining) has been shown to adversely affect children's health, independent of the child's physical activity levels. Adverse associations between sedentary behaviour and risk factors for disease, such as obesity, blood pressure, and high levels of cholesterol have been observed in children. In addition, prolonged sedentary behaviour has been linked to reduced cognitive development and academic achievement in children.

Changes in our environment and lifestyle have resulted in children not only becoming less physically active, but also spending unnecessarily long periods of time sitting, particularly in the classroom. Sedentary behaviour is the most prevalent behaviour exhibited by children in developed countries, comprising >65% of waking hours. The impact of unhealthy lifestyle behaviours, such as prolonged sitting, on children's health and development is concerning given the importance of childhood for the establishment of lifestyle behaviours that can track into adulthood.

The long term vision of our research is to re-address the balance between sedentary and non-sedentary (i.e. standing and all forms of physical activity) behaviours by changing environments which are traditionally associated with prolonged periods of sedentary behaviour, such as the school classroom. This study will make environmental changes to the classrooms of Year 5 students (aged 9-10 years) from one school in Bradford, in the UK, through the provision of manually adjustable sit-stand workstations. The primary aim is to compare the effects of this novel strategy using both full desk allocation (one per child) in one classroom and partial desk allocation (six standing desks in a class along with standard desks) in a second classroom on children's classroom sitting and standing time. Comparisons will also be made between the two intervention classrooms in the one school to children's sitting and standing behaviour measured in a control school (following usual practice). Secondary aims include evaluating the effects of the two interventions on time spent in different intensities of physical activity, health, learning and cognitive function outcomes.

This study expands on the success of the nine week pilot study, conducted in 2014, by implementing the intervention over a full academic year, having an additional intervention group, including an extra school for a control group, and including more key outcome measures (blood glucose, self-reported comfort) to better understand the impact of sit-stand desks. If successful this study will support the concept of sit-stand desks as an effective long term school based intervention for benefits in health and learning in children across all demographics

Inclusion Criteria:

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Exclusion Criteria:

• Any child with any disabilities that prevent them from standing up for short periods of time will be requested to continue with their usual practice of sitting at their school desk.
• Children with any disabilities or injuries/illnesses that prevent them from going about their usual routine will be excluded from the evaluation component of the intervention