Children are being pushed towards team sports, suggests research
An over-emphasis on competitive team sports in schools is being blamed for "marginalising" the wider efforts to promote physical exercise.
Research from Loughborough University suggests that healthy individual exercise is losing out because PE teachers want to focus on team games.
This means that pupils are not learning about personal exercises such as aerobics and pilates, say researchers.
But England's education department said it was "bemused" by the report.
The study, being presented to the British Education Research Association's annual conference in Edinburgh, has been based on interviews with 112 PE teachers in a range of local authorities in England.
The research has found that it will be difficult to promote the idea of individual health-promoting exercise when lessons are likely to be dominated by teachers' personal interest in team sports.
"A teacher who has experienced lifelong success in sport is likely to want to focus upon competitive team games within lesson," says researcher Laura Ward.
"This then presents us with a persistent cycle whereby sport is privileged within PE and health-related exercise is marginalised."
School sport has been seen as an important part of efforts to tackle the problem of childhood obesity.
The government says a target to get 85% of youngsters in England doing two hours of sport a week has been met - and it wants that to be increased to five hours per week by 2012.
Last year the former education secretary Alan Johnson attacked those who argued against competitive team sports in schools.
"It was an absurd and perverse political correctness which caused competitive sports to be banned in some schools and I hope we never see a return to such nonsense," Mr Johnson said.
A spokeswoman for the Department for Children, Schools and Families said: "We're frankly bemused by this research.
"Solo exercise like dance and athletics are in the top five most popular sports in schools and participation rates in PE and sport have soared - from less than a quarter doing two hours a week in 2002 to almost nine in 10 now.
"The fact is that young people thrive off competitive sport, particularly team sports - three million children took part National School Sport Week in June and the 1,500 elite teenage at the UK School Games last week.
"And we are investing £30m specifically into promoting competitive sport further through regional, borough and school leagues and inter-school fixtures."