Hundreds of pupils have taken part in protests at Westminster against cuts to school sports funding.
Demonstrators handed in a 500,000-signature petition to Downing Street, calling for the £162m School Sports Partnership not to be axed.
More than 70 top athletes have also written to David Cameron, saying the policy is "ill-conceived".
Last week, the prime minister said that the government was looking again at its plans.
Funding for the Schools Sports Partnership - made up of 450 joint initiatives between primary, secondary and specialist state schools and designed to increase sporting opportunities for children - has been cancelled.
But the government says it is looking at the best way to to achieve the goal of increasing participation in sports at schools.
In their letter to Mr Cameron, athletes including Olympic heptathlon champion Denise Lewis and world diving champion Tom Daley say ending the partnerships risks the 2012 London Olympics' "genuine legacy" of encouraging participation in sport.
They urge the government to reconsider the withdrawal of direct funding from March.
Last month, Mr Cameron described the partnerships as "a complete failure".
However, at last week's prime minister's questions, he said he was "looking very carefully" at the issue and said new proposals would be brought forward, although his aides and cabinet ministers denied this was a U-turn.