I was never good at PE at school, nor interested in getting good at it. Somehow, I knew the best way to endure it was to be enthusiastically bad, overestimating my ability for a laugh or begrudging respect from a teacher. I would voluntarily do butterfly against the county swimming champions, purely because I found it funny.

Secretly, maybe, I wished I was naturally sporty. In my early 20s, I had more important things to do than fitness (drinking and watching Mad Men), but by 25, I realised it was time to get moving. I tried running and the gym. Then, with the help of a powerfully shredded trainer, I discovered weightlifting.

I like proving I can do things people might not expect of a young(ish) woman, things more often associated with big buff men. So I got the gloves and belt, and marvelled at how quickly my thighs turned to rock, yet felt like rubber when I bounced up an escalator. Lifting was like getting a mental scrub: every muscle fibre and shred of concentration united in exertion. I felt satisfaction at often being the only woman in the weights room.

Yes, there was the shrieking horizon of pain expanding across the base of my spine, and it was becoming a struggle to stand up from my desk chair, but so what? I could lift more than I weighed. Watching the discs that crown the bar get bigger was a visible reward.

And then – bet you didn’t see this coming – I did myself a massive mischief. While I was doing a goblet squat, that throbbing slab at the bottom of my back went thunk, in a dramatic, fleshy surrender. To make sure something really bad had happened, I tried pulling a big weight on another machine. Yes, something bad had happened – and I had probably just made it worse.

Since I could no longer put my pants on from a standing position, I started physiotherapy, meeting weekly with a lovely woman who told me I had a slipped disc (also known as a herniated or prolapsed disc). As she dug her elbow into my bum (apparently almost devoid of muscle owing to the terrible technique that landed me face-down on her table), it appeared she could read my mind through my arse. Why did I feel I had to push myself to extremes? Had I been an overachieving child?

The reasons that got me there became embarrassingly obvious. As a kid, I was not allowed to get away with doing less than 110% at school (other than in PE). And with two younger brothers, I was acutely aware of gendered unfairness and needed to prove I could outdo any boy. Into adulthood, I thought prolificacy could compensate for low professional self-esteem, and worked myself like an abused greyhound. Limits? Nah.

My physiotherapist’s kind bafflement at my appalling need to be the best made me see how silly it was – especially at the gym, where I was only competing against myself. It was not just OK to listen to my body when it hurt or my mind when it short-circuited, it was key for long-term wellbeing, not to mention my wallet: I still have to have physiotherapy every eight weeks, and see a trainer who works with the physiotherapist to tailor sessions appropriately.

Slipping a disc obviously is not a change I planned to make and, while it sometimes gets me out of doing the vacuuming, it is one I would reverse given the chance. But – not being particularly given to introspection – I doubt I would have stopped ragging myself in the name of meaningless accomplishments without being physically forced to.

My back is mostly better – thanks in part to the careful development of some now cartoonish and very supportive bum muscles – but it will always be precarious, a constant reminder of what I now understand are acceptably human limitations. I tried a white-collar boxing class this summer. It turned out to be a fetid industrial estate gym, all men bar me. I loved it. It was another extreme to conquer. But reason overpowered adrenaline: it was a bad idea to let blokes pound my puny hands as I took my turn holding the pads. I didn’t go back.

Recently, my trainer said I could start lifting again, using a hex bar – a bigger frame that encourages better technique. All the old feelings returned, the exhilaration crackling through my muscles as I lifted 42kg, then 52kg. But I listen when he tells me not to lift more when I go to the gym independently. And I no longer take the gloves or belt, just my strongest attempt at common sense.