Thousands of children in England have been issued with pedometers to try to encourage them to take more exercise.
Children are being encouraged to be more active
The Schools on the Move pilot scheme is part of a Department of Health initiative to tackle childhood obesity.
In total, nearly 9,000 pedometers - which measure how many steps someone takes - were issued to nine to 14 years olds in around 50 schools.
The government has pledged to halt the year-on-year increase in obesity among under-11s by 2010.
It also wants all school pupils to receive two hours of PE and sport a day by 2010.
Launching the scheme, public health minister Caroline Flint said: "Childhood obesity is a serious issue which the government is determined to tackle on a number of fronts including increasing levels of physical activity.
"Pedometers are effective in motivating people to become more active."
The information children gain from their pedometers will be incorporated into lessons like maths, science, art and geography.
It is hoped this will make the distance they walk and the number of steps they take relevant across the school curriculum not just in PE and school sports.
Ms Flint said: "Every little bit of extra physical activity we incorporate into our lives can make a huge difference in terms of health improvement.
"By raising awareness of the importance of physical activity amongst teachers and pupils and by encouraging children to become more active, we hope to make big strides in reducing childhood obesity."
The project, a joint venture between the Department of Health and Department for Education and Skills, will be managed by the Youth Sport Trust.
Steve Grainger, chief executive, said: "Taking the physical activity message into the classroom and day to day school life is a major step forward in encouraging all young people to be more active on a daily basis."
Schools from the following local education authorities are taking part in the project: Barking and Dagenham, Bradford, Devon, Leicester, North Tyneside, Nottinghamshire, Oldham, Suffolk, West Sussex and Wolverhampton.