A campaign to make sport a part of every child's day has been announced by Prime Minister Gordon Brown.
Building on an earlier drive, he wants all school children to get the chance to do five hours of sport a week.
Teenagers aged 16-19 at further education colleges or out of education, employment or training, should be offered three hours a week.
Currently children under 16 are required to do two hours a week within the national curriculum.
But since 2004, the government has been encouraging schools to offer pupils an extra three hours of sport on top of this.
The new £100m package announced by Mr Brown will mainly be used to target older teenagers not in school through community and local authority sports provision, the Department for Children, Schools and Families said.
It builds on about £600m of funding already announced to support the take-up of PE in schools over the next three years.
Mr Brown called for a "united effort" to make sport a part of every child's day in the run up to the 2012 London Olympics.
He said: "I was lucky enough to have primary and secondary schools that had sport at the centre of their ethos. I want every child to have that opportunity to take part.
"Watching sport is a national pastime. Talking about sport is a national obsession. But now we need to make taking part in sport a national characteristic."
Parents, volunteers, coaches and the sporting world are also being encouraged, alongside schools, to get more youngsters involved in sport.
The push includes a new National School Sport Week, in which schools will be urged compete against each other, and a new network of 225 competition managers to work with schools to increase access to competitive sports.
PE teacher shortages
But the shadow culture secretary Jeremy Hunt said the new funding failed to address all the issues surrounding children's participation in sport.
He said: "As usual when you look at the small print this turns out to be a classic piece of Brown spin.
"£100m between now and 2012 turns out to be £20m a year, less than a tenth of the reduction in funding to grassroots sport as a result of his lottery raid to fund government pet causes.
"Whilst we welcome any initiative that increases participation in sport at schools, he has totally failed to address the shortage of trained PE teachers, the drop-off rate in sport participation when people leave school and the lack of links between schools and community clubs."
Liberal Democrat culture, media and sport spokesman Don Foster said the government had promised to increase funding for grass roots sports before but they had an appalling track record in making young people more active
"They pledged £750 million in lottery funding for grass roots sport seven years ago yet they've still only provided a fraction of it.
"£100 million is a drop in the ocean when the Government continues to sink money into the Olympic budget black hole."
However a DCSF spokesman said the new money was specifically being used to target school leavers and those in FE colleges.
Currently, 37% of pupils take part in sporting competition between schools, and 71% within their own school.