The school has put on the event to raise cash for Derian House Children’s Hospice, in Chorley, for the past six years.
And organiser Wayne Hartley, assistant head at the school, said the total raised over the years had tipped the £10,000 mark.
Starting at 8.45am and going right through 3.15pm, children exercises including lifting weights, sit-ups, press-ups, star jumps and skipping, with only the 10-second breaks.
Mr Hartley said: “I am amazingly proud of them all. For me this is the biggest day of the year. In the past, this has led to some of the pupils going on to do voluntary work.
“We had four ex-pupils back this year who had taken part in the past and want to come back to do it.”
Mr Hartley said the circuit training club had been running for 12 years and since starting the charity event it had really taken off.
He said: “We started with six children who raised £400 between them.
“The idea first came as we wanted children to support a children’s charity and they all love it. They are so proud of what they achieve. I see them grow a foot.
“And the support from Derian House is immense and they come down and cheer them on.”
Jill Kirkham, from the fundraising team at the hospice, said: “We would like to say a massive thank you to the pupils and staff at Darwen Vale, for choosing Derian House and for their ongoing support.
“The children are a real credit to the school.”