In a chilly corner of a city centre gym, a group of robust arm-wrestlers engage in a testosterone-fuelled display of virility. This ensemble of hardy competitors has only been coming together for a few weeks, but they are already attracting champions from all over the country.

They come to compete on The Grappler – the only arm- wrestling device of its kind in the world.

Designer Rod 'Rambo' Lenette, 44, is the former world, European and UK arm-wrestling champion, who is not afraid of anyone.

And his courage and conviction are more than evident when you hear his medical history.

After suffering kidney failure, Rod spent six years on dialysis before finding a donor and making a full recovery.

He also suffers from diabetes and another condition, which means his body is unable to produce fat.

And that is on top of losing half his left bicep in an industrial accident.

"I've been through a lot, but it's made me more determined," he says. "I want to be the best, and I've still not hit my peak.

"People always ask which victories I remember most – but it's the defeats I remember, they're the ones that stick with me and I learn from each one."

So, the former champ invited me to try out his unique invention.

"You ready?" he snarled.

Rod, a mechanic, was quick to run through the rules as two large gentlemen were locked in combat next to us on a traditional arm-wrestling table.

The Grappler is anything but traditional.

"You strap your arm in here and with your other hand you operate this handle – pushing and pulling the handle throws your opponent off balance," explained Rod.

He asked Mercury photographer Alex to wait while he secured his trademark camouflage headband and warmed up his fearsome battle grimace.

"At the same time, you can swivel the machine 360-degrees in either direction – and you see how the platform is red and blue? Well, you can only pin your opponent when you're on your own colour. It's taken arm-wrestling to a total body sport."

Rod and I were 'strapped in' and locked hands.

"Go," shouted Rod.

We circled each other as we tried to gain an advantage.

(I should point out here that I'm making it sound as if I stood any chance – in reality I had no idea what I was doing and was just pleased my arm was still in its socket).

"Technique is everything," said Rod. "The beauty about The Grappler is that anyone can beat anyone on their day."

Yeah, right. He beat me three times in a row.

Watching my crushing defeat was another UK champion, Dean Scarsbrook, of Thurnby Lodge, who stumbled into the sport about four years ago.

He has an incredibly rare condition which means he is unable to sleep.

Eight years ago, Dean was involved in an accident which damaged the part of his brain which enables him to nod off.

"I'm on all sorts of drugs which knock me out, they put me in a type of coma every night – and every morning I wake up feeling awful," he said.

In 2008, unable to work because of his condition, he needed a hobby and went along to watch an open arm-wrestling tournament called the New Year Cup. He entered on a whim – and won.

He said: "It's a great sport, I've made some good friends and the feeling of camaraderie is fantastic.

"We want to encourage more people to come along and give it a go – and it's not just about brute strength, it's about technique and passion."

The group – Armed Combat – meet at the Urban Martial Arts gym, in St John's Street, near St Margaret's bus station.

The gym is owned by Gok Wan's older brother, Kwoklyn, who said: "The Grappler is the only machine of its kind and we're proud to have it here.

"It's going to transform the sport and take off in a big way – it's already had a lot of interest from other parties."

The sessions run on Wednesdays, from 8pm until 10pm.

For more information, visit:

www.urbanmartialarts.com