According to Canberra researchers, school children who didn't find physical activity fun at school were likely to never enjoy it and lead shorter, less healthy lives.

University of Canberra associate professor in sports and exercise Richard Keegan said it was not important for children to be good at sport as long as they developed an enthusiasm for movement.

Much of the responsibility for this rested with school teachers, who were rarely PE specialists and were pushed for time to create vibrant lessons in a crowded curriculum.

''The problem is some kids are doing PE during school and hate it so much that they never do it again,'' Dr Keegan said.

Dr Keegan said studies had shown children who watched television for more than six hours a day could have a decreased life span by up to five years, while the cost of physical inactivity to the economy could be more than $10 billion a year.

''You don't have to get out of breath, but just be able to move and interact is important,'' he said. ''If we can make a generation who love moving, it will be very beneficial.''

Dr Keegan said schools were not entirely to blame for unmotivated students and that more research in the area needed to be done.

''Whatever we are doing right now isn't working and we should look at everything we can,'' he said.

Wendy Gillett, chief executive of The Bluearth Foundation, which promotes active lifestyles in school children, said more should be done outside of the classroom.

''Moving isn't expensive - it's actually a big expense not to move,'' Ms Gillett said.

Australian National University researcher Professor Dick Telford, who has been conducting the Lifestyle of Our Kids study, said aerobatic fitness levels had a direct correlation with literacy and numeracy results.

''It's much easier to say 'well, just go for a run around the block', but that doesn't instil the love of physical activity. It might be OK now and then but it's not the sort of physical education a trained physical education teacher will design,'' he said.

Mother-of-two Emma Spannari said restrictions in school playgrounds limited how much fun kids could have. ''They're not allowed to do cartwheels, handstands or hang upside down on the monkey bars,'' she said. There's just too much they can't do.''

Clarification: This article initially could have implied Mrs Spannari's criticisms were of the YMCA where her children were attending a school holiday program. This was not the case.