SO researchers have proved what generations of slothful schoolchildren picked up by osmosis: that it is possible to avoid exercise in PE lessons.
The time-honoured technique of skulking at the back shouldn't be underestimated: lessons spent avoiding being picked for teams and conniving to be sent to distant outfielding roles are invaluable preparation for adult life.
At least, they were in the days when children routinely walked to school and played outside at every opportunity, unfettered by electronic entertainment and parental fears of dangerous traffic and worse.
Now ther are real worries about the long-term health implications for the nation's increasingly inactive offspring. Five years ago, a third of six to eight-year-olds spent two hours a week doing PE:now just over 10 per cent do.
Government advisers are investigating how school sporting standards can be raised: perhaps they will consider the researchers' conclusions that cutting staff-pupil ratios in PE classes to below 20-1 would force more running and less hiding. Society is making increasing demands on schools, but building the foundation for pupils' health must be a high priority.