I’ve got a problem with my ankles.

I went on Google, typed in ‘pain at back of ankles’ – and diagnosed myself with Acute Achilles Tendonitis. It’s basically a serious-sounding name for puffed up ankles.

The reason my ankles have puffed up is because I’ve been attempting to walk/run/trot 20,000 steps a day. This madness began when I acquired a Jawbone UP band, which you wear around your wrist to chart your activity during the day – from calories burned, hours slept and the amount of steps you complete.

An average active human should be walking around 10,000 steps a day. But being the competitive type, I wasn’t happy with a mere 10,000 – so I rather ambitiously set my target to double it.

The problem with attempting to do 20,000 steps a day is that despite running 5km on the treadmill, sweating it out on the cross trainer for half an hour, and then spending the rest of the day galloping up and down the stairs at work, by the time I get home, I’m still about 3,000 steps short of my target.

This has meant that most evenings, the husband had landed back from work to find me pacing around the living room like a deranged Duracell bunny.

Another feature on the UP band app is that you can add friends who also have this step-counting device. I only have one friend: Anna. I can see how many hours sleep she gets, what she been eating and – most importantly – how many steps she does in a day.

It’s all rather competitive and, if I’m being perfectly honest, a little bit stalker-ish.

I was quite happily charging around for about three weeks, revelling in the knowledge that I was one if the top steppers in the UK (and beating Anna’s steps on a daily basis), until I woke up one day and realised I could barely walk. My ankles had seized up.

My wails of, ‘I’ve got cankles on my ankles!’ were met by complete indifference from the husband, who has long been impervious to my hypercondria.

Incidentally, I haven’t got cankles on my ankles. I didn’t even know what cankles were but the rhyme seemed to add a certain seriousness to my situation.

(I then googled ‘cankles’ and realised to my horror that it’s a condition where the calf meets the ankle without tapering at all. In short, your legs resemble those giant inflatable tubes they put down the sides of a ten-pin bowling lane for beginners. Thankfully, this isn’t an affliction I’ve been cursed with after all).

However, when I casually mentioned that my Achilles’ tendon might be the source of the problem, the husband put down his New Scientist magazine and suddenly looked serious.

‘If it’s the Achilles, you need to stop exercising immediately,’ he said gravely – probably having horrific visions of spending the next 50 years pushing me around in a bath chair, while I bark orders at him.

‘If your Achilles snaps, it will be VERY serious,’ he added.

So there we have it: I can’t go to the gym. I can’t pound the pavements watching my steps rack up. I can’t canter up the stairs at work, two at a time, thinking, ‘steps, steps, glorious steps’.

No. All I can do now is meekly hobble round like a stiff-ankled sloth, knowing that – if I’m lucky – I might clock up a paltry 5,000 steps, while receiving updates on my UP app that say: ‘Anna has completed 18,000 steps today.’

I should be mourning the fact that I can no longer exercise and that my ankles will soon turn into giant squidgy sausages.

But knowing that Anna is achieving the top 5 per cent of steppers in the country, while I’m languishing in the bottom percentile, along with the injured and the infirm… now that’s my real Achilles’ heel.