Great heights... can a workout really make you taller?

My wrists and ankles have been clamped into a medieval torture rack-type machine and I am being stretched, slowly and painfully. This isn’t a scene from a 13th-century period drama but the dramatic finale of A-Grow-Bics, the workout guaranteed to make you taller.

It’s led by Gymbox trainer Pierre Pozzuto, who grew by almost one and a half inches while devising the class. I’m 5ft 6in but have always wanted to be a little taller, and with leggy models on their way to London Fashion Week reminding me that I’m on the shorter side of average, I book myself in for a session with Pierre. Over six weeks, he promises up to two centimetres of growth, or your money back.

There’s no gentle easing into this workout — Pierre starts by getting me to hook my legs around one of the high bars and hang upside down, relieving pressure on the nerves of the spinal column and strengthening leg muscles and abs. I feel like I’ve reverted to being seven and playing on a climbing frame. But after a day hunched over my computer the stretching is welcome.

The workout lasts an hour. It’s a mix of high-intensity cardio (squats and aerobics), yoga and Pilates — to lengthen the spine and improve posture and muscle alignment — and repeat sprinting, which causes microfractures in the bones that repair in a week encouraging them to strengthen and grow. This is all rounded off by a thorough stretching on the torture rack.

It won’t make me as tall as a supermodel but it is a varied workout that builds muscle all over the body, and thinking about my poor hunched spine encourages me to stand taller. I won’t be binning my high heels yet but after my trial session I’m willing to try out the six weeks of training.

A-Grow-Bics is a six-week course of one-on-one training at Gymbox Holborn. It costs £200 and is bookable via gymbox.com.