What is it? The decades-old craft of Pilates, performed on a piece of equipment that occupies the middle ground between a rowing machine and a particularly grim medieval torture device.

How much does it cost? It varies. I had a class at London’s Bootcamp Pilates, where it’s about £20 per session.

What does it promise? Weight loss, increased flexibility and, perhaps most importantly, aggressively fast toning. Joseph Pilates himself apparently once said, “You will feel better in 10 sessions, look better in 20 sessions and have a completely new body in 30 sessions.”

What’s it actually like? If Joseph Pilates was being totally honest, he should have ended that quote with, “but after one session you’ll be rubbish at going up and down stairs for a few days”. That’s my take-out from my Reformer Pilates workout; I could hear my upper thighs pleading for clemency while I was doing it. None of it looks that difficult – it’s all just flexing and stretching, and pulling yourself up and down the machine on its elaborate spring and pulley system – but an hour of holding yourself in what basically amounts to a series of CIA stress positions ends up being total agony.

Best and worst bit? The best bit, inevitably, comes early. “Is this it?” you think. “This is a piece of cake.” The worst part comes towards the end, when you have to perform a stretch with a plastic hoop jammed between your legs, and holding it there hurts so much that it keeps falling out, and the instructor has to keep putting it back in for you, like you’re a baby.

Is it worth it? You may be surprised to hear this, but I’m going back next week. So maybe it is.