Pilates became huge in the 90s, lauded for powers that seemed quasi-mystical: it made you calm down, but it also made you longer and tauter. It was never clear exactly how it could make you lose weight, but “longer” and “tauter” sounded a lot like “thinner”. Dancers did it because it was one of the only things you could do with a ton of historic injuries; those of us who had never done enough exercise to amass any injuries did it because dancers did.

Reformer pilates is a little more recent, as a craze, a lot more involved, in terms of hardware, and a lot more expensive. (The class I went to, in Clapham, south London, was £21 for an hour, which would make me think twice. Or maybe I’m just tight.)

The hardware is a sprung bench (no giant beach ball here). You lie on it, there are straps you can put your legs in, straps you can put your arms in, and five springs of varying strength, which determine the difficulty of each exercise. Its peculiar design enables you to do things you wouldn’t – without leg straps, a movable bench and some spring – be able to do, like a shoulder stand. There’s one piece of equipment with a frame over the top, in which you can get practically upside down and feel like an acrobat. It’s important to remember that your human strength hasn’t changed, and no self-respecting circus would employ you.

I went with two friends, though luckily they were behind me, so I didn’t have to measure my failings against their success. You start off like a ballerina in stirrups, pointing your toes and flexing your legs towards different parts of the room. The instructor had a very evolved sense of direction, in which – so far as I could make out – she was alone. “Legs towards the high street! Shoulders up, legs towards the south wall.” Horizontal, and trying to move multiple limbs at once, I can just about remember which way is up. The concept of north is a world away. We were basically just watching each other and copying whoever seemed the most certain. It is all very hard on the muscles: controlled, sustained anything, if you keep at it for six minutes, will kill your hamstrings or anything else involved.

Fit in my 40s: ‘It’s more than yoga – it’s a complete system for loving yourself’ Read more

About halfway through, the standing-on-the-bench commences, which seems as if it will be easier, because it looks it. One foot on the static part of the bench, one on the moving part, you slide your working foot in and out like a character in an 80s computer game of warrior bearing but limited skills. It turns out who knew? – that this is hard, too.

The “reformer” element adds complexity and unexpectedness, which makes the time go faster but doesn’t make it feel any easier. I had the vague expectation of a mindfulness component, mainly because the kind of people who like pilates also like yoga. But this is not an activity in which you can drift off and connect with the true you. It requires the same level of concentration as driving on a motorway at the same time as having an argument; which is in itself is quite mentally cleansing. I’d go regularly if I had a pilates buddy; without, it’s a bit ponderous.

Give it a go

Find a class where you live at pilatesnearyou.co.uk

• Clothes: My Gym Wardrobe