Children who attend primary schools in deprived areas of England are to be given pedometers in an attempt to encourage them to be more active.
It is hoped the pedometer will encourage pupils to be more active
The £494,000 scheme will see 45,000 pedometers, which measure the number of steps taken, handed out in 250 schools.
Pupils will chart their progress by logging on to a website that sets targets for their number of steps.
The scheme follows a pilot in 50 schools which showed increases in children's activity levels.
The trial scheme for pedometers found 63% of children who took part thought it had increased interest in physical activity in their school.
And step counts increased from an average of 8,355 steps to an average of 13,939 at the end of the 23 week programme.
Government advisers say children need at least one hour of at least moderate intensity exercise per day.
Figures show 30% of boys and 40% of girls are not reaching the recommended activity levels.
Making exercise fun
The Schools Minister, Jim Knight, said: "Walking is one of the easiest ways to exercise and pedometers can make it more fun for children.
"Schools are already increasing children's activity levels by boosting the opportunities to take part in PE and school sport.
Health experts say children need to be more active
"Pedometers can be especially effective in encouraging young people to be active out of school hours and at weekends."
Public Health Minister Caroline Flint said: "Using pedometers in schools has successfully encouraged children, especially those who do less exercise, to become more active, so I am pleased to announce that this scheme is being extended.
"It is particularly impressive that the children's' enthusiasm for pedometers has led to whole families becoming fitter as children have been so eager to improve their step count they have persuaded their parents to do things like go walking with them, or join an exercise club.
"We know that obesity prevalence is often high in deprived areas and schools with high levels of obesity will therefore benefit from the national school pedometer programme."
But the Liberal Democrats dismissed the scheme as a gimmick.
"The scheme risks merely measuring how little exercise some pupils do without helping young people to lead healthier lifestyles," said health spokesman Norman Lamb.
"Money promised by the government to improve sports facilities in schools is not getting through, while the number of playing fields has declined.
"Labour is tinkering round the edges of the problem of childhood obesity. Unless fundamental action is taken now we will have an entire generation facing type two diabetes, heart disease and premature death."