What is it? Electrical muscle stimulation: a workout you perform while hooked up to electrodes that are plugged into the mains.

How much does it cost? I had a session at Exerceo in Aldgate, London, which charges between £35 and £50 a go. However, studios are sprouting up across the country.

What does it promise? According to my trainer, Nooroa, the worst 20 minutes of my life. A workout here, with electricity pulsing through your muscles, is apparently the equivalent of a 90-minute regular workout. Usain Bolt’s a fan.

What’s it actually like? Guess what? The worst 20 minutes of my life. You arrive, dress up like the world’s most terrified Tron extra, and then the pain begins. A lot of the session is ostensibly light bodyweight work (squats, lunges, press-ups) but made several times harder by dint of the fact that you’re basically incapacitated by electricity.

An example: Nooroa asked me to do bicep curls and handed me some paltry-looking 3kg weights. He then turned the machine on and, embarrassingly, I could barely lift them. I was tired after three minutes. I was gasping for breath after 10. At 15 minutes, I couldn’t wait for the bloody thing to be over.

It was awful, but what a workout. I mean, I’m writing this the next day and I can’t really move my arms, but I’m still going back next week.

Best and worst bits EMS training offers one of the most intense workouts you’ll do, and you can easily fit a session into your lunch break. But Jesus Christ, everything hurts. Everything hurts so much.

Is it worth it? Yes. Then no. Then yes.