A promising study can be very small. Thirteen teenagers, teachers doing the rating, and a fortnight of follow up is a good start and not a settled answer.

When somebody does not take up the movement you suggested, ask what got in the way before deciding they did not want to. Usually it is money, childcare, transport or time.

Give a new habit two months rather than two weeks, and change one thing at a time. The old line about thirty days sets you up to feel like a failure on day thirty one.

Arrange to meet someone. A neighbour at the gate at eight, a friend expecting you, even an app counting a streak. Turning up for someone else is easier than turning up for yourself.