If a child is climbing the walls, green space helps most, a walk down a busy street helps a bit, and staying in the room helps least. Any of the three beats none.

Children need to move before school, during it and after it. Keeping a child in at break until the work is finished takes the movement away from the very child whose finishing depended on it.

An hour a day of moving enough to warm you and shorten your breath. Keep a record of it, on a watch or on a scrap of paper, because meeting a number you can see turns out to be quietly satisfying.

Movement gives you back some willingness, not just some focus. The problem is often not that you cannot concentrate but that you cannot make yourself care enough to start.