NEVER trust a man who tells you there is a “nice way” to burn out.

This applies especially when he is a 50-year-old personal trainer with the body of a 25-year-old athlete who claims to offer professional standard strength and conditioning training to anyone who’s game.

He is Erik-Lee Briscoe and he runs Team Shape-U, putting his 50 clients through an ever-changing series of gruelling exercises and circuits in Brockley's Hilly Fields Park.

They include the VertiMax: a large, square board bristling with elastic cables which provide resistance when you strap them to your limbs, making even simple exercises much more difficult and tiring.

It cost Erik-Lee £4,000 to buy and import from the U.S. and he claims he is the only trainer outside professional football clubs to have one in this country.

Add to that punch bags, speed balls, battle ropes and two different-sized sets of hurdles and this is a long way from banging out a few bench presses in the gym.

Erik-Lee tells me it’s all about working with your body and finding its limits rather than trying to break yourself. He said: “Most sportspeople in this country don’t do proper strength and conditioning.

“They are not really being tested so that their bodies burn out in a nice way.

“Everybody thinks it’s all about running yourself into the floor and beating yourself up.

“With this you never get injured because your body is working naturally.”

After three circuits of eight exercises, I am feeling far from natural but it’s also clear my body has never been worked quite like this.

Triathlete Carly Lynch, 30, has been training this way for a year and a half and is heading to Berlin this weekend for the half marathon.

The psychiatric nurse and former long distance cyclist said: “I used to go to the gym but I just hit a plateau.

“It’s really helped me with my running.”

It’s possible to see how this could be addictive: one because you have to try and beat the number of repetitions you did last time on each exercise, and two because the rush of endorphins afterwards is intense.

Erik-Lee adds: “The only way you can get a muscle strengthened is to get it freaked out but in a nice way.”

There is nothing nice about Shape-U but before the morning-after pain kicks in, I am thinking I wouldn’t mind another go.

Visit shape-u.com