I bought three tennis balls today. Not to play tennis, obviously. And I only wanted one, but they only come in tubes of three. (And why are they sealed like tins?) I've discovered you can do self-massage with tennis balls, so decided to try as I am at my wits' end, having tried every back stretch known, and I can't keep taking 30/500 co-codamols. I feel like an impostor in sports shops, everything seems alien. Still, I told the woman why I needed the balls and pointed to some glittery ones I liked the look of. Those are for hockey, she said, those would break your back. Glittery hockey balls, I replied, we didn't have such a thing when I was at school! I heard myself sound like my mother and acknowledged (to myself) these are the kind of things you say in your forties.