The Scottish Government has been forced to clarify its physical exercise targets for pupils, in the wake of comments by its schools minister.
Maureen Watt told BBC Scotland plans for two hours' activity per week could include non-curricular activities, such as walking to school.
The government later said it was committed to two hours of PE and extra opportunities, outside the school day.
The Liberal Democrats said the policy was "all over the place".
Outlining the government's vision on BBC Radio Scotland's Scotland at Ten programme on Tuesday, Ms Watt said: "What we're saying is we're going to make sure that children have two hours of good physical exercise every week.
She added: "That could involve walking to school."
The minister insisted: "We're making sure children have good physical exercise. It involves using the whole school day to make sure children get two hours of physical education."
In a statement on Wednesday, the government said it was committed to a minimum of two hours, quality PE being offered by schools as part of the curriculum.
It went on: "In addition to this, physical activity and sport will offer extra opportunities to children outwith these two hours during break times and lunchtimes and beyond the school day."
Lib Dem health spokesman Ross Finnie said: "The SNP is all over the place on physical exercise targets for children.
"There is confusion as to how it fits into the SNP's stated aim not to be prescriptive about how long schools spend on any particular subject."
Ms Watt also refused to say whether the SNP manifesto pledge to ensure every pupil had two hours of quality PE each week - carried out by specialist PE teachers - would be delivered in full.
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