The most important lesson I’ve learned in the whole great arc of my fitness career is: just because you hated it the first time, doesn’t mean it’s not for you. This is why I returned to Pilates, which I previously felt was like soulless yoga (functional, painful, boring). Plus I was persuaded to try again by a friend – not by her words, but by the way she looks: like a dancer, except not haughty.

We went together to a local teacher called Dario Novo. It was reformer Pilates: long benches with weighted springs that you adjust according to your ability and the exercise, plus multiple straps to truss yourself into when you want to do something especially complicated to your arms and legs.

Pilates moves are not especially graceful or exhilarating; it’s one foot (or arm) on the frame of the bench while the other slides the moving part backwards and forwards. This is nursery slope stuff, of course, but the principles are control, slowness, repetition, and this is not something I can immediately understand with my body. It really helps if someone explains what the purpose is, and the mechanisms for it.

The exercises are designed to work groups of muscles to the point of failure: it’s not commonly associated with gentler pursuits like Pilates and barre work, but they work on exactly the same lines. To get your muscles to the point of failure, you need to work through four motor unit types. Your body “recruits” fibres in a given order: slow twitch first; then, when those fail, the intermediate muscle fibres; finally – in the Novo Pilates model, during the last two to 20 seconds of the set – your fast-twitch fibres. As you progressively overload each element of the muscle, you get the greatest metabolic response.

The best analogy I’ve read is that it’s like overtime: when you get to that stubborn last line of defence in the muscle, you’re effectively paying double for the same move.

The bit that remained mysterious was that it didn’t feel painful, as such: one minute I was pushing a limb in and out in a leisurely fashion, then 60 seconds later it just stopped. I simply couldn’t. Usually when I’m about to fail, I have an early-warning system of at least five minutes, if not a day, during which everything that comes before is unbearable. The sheer precision of these manoeuvres is incredible.

This won’t sound like a ringing endorsement, but the next day, I thought I had flu. It wasn’t the self-righteous exhaustion of strength training; it was a semi-enjoyable, unfightable, full-body weakness, the kind of thing that happens to someone in a novel when they’ve had an epiphany or been poisoned. It helped that I could stay in bed all day. Again, that doesn’t sound like a recommendation, but it is. It may be the first time I’ve understood a fitness objective, done the fitness thing, and seen the objective realised.

What I learned

Never use momentum to complete a move: make your muscles do the work