I worked out with a £1,000-per-hour personal trainer - his clients include Olympians, CEOs, and celebrities

"Sport is in my blood," Fabrice said. "I was playing table tennis as soon as I was out of my mother’s womb."

As well as following in his father's footsteps and becoming an African table tennis champion, he excelled at football. It was then that he was first christened Fabrice Le Physique. His friends expected him to be the next Samuel Eto'o, a Cameroonian professional footballer who plays as a striker for the Turkish club Antalyaspor.

In 2005, aged 17, Fabrice came to the UK to pursue a professional football career. He signed for Fulham under Chris Coleman, where he played for the reserves. He then moved to Stoke City, but a chronic groin injury ended his career after just one year.

"It was tough," Fabrice said. "It was a passion I had to leave behind."

To pay the bills, Fabrice began a successful modelling career with Nike, Adidas, and Coca-Cola.

As well as modelling, Fabrice began training other footballers. Teaching was a skill Fabrice had learned as a child.

"I was already training adults when I was 12 years old," he said. "One of my main drives is to inspire people, and get the best out of people."

He took a job at Virgin Active, where he quickly began breaking company records for the number of sessions he was working.

One day Fabrice's boss called him into the office. "I think you need to have your own business right now," he said. "I'm your general manager, but you are earning more than me because of the amount of sessions you are pulling in."

Fabrice was immediately successful in building up a list of customers and in 2011 he set up Munsterfit, which now employs 25 personal trainers around the country.

One hour with Fabrice can cost anything from £200 per hour to £1,000. It depends on the level of demand at the time. On an average week, Fabrice delivers 25 to 30 sessions. However, in January, this can rise to 40 sessions per week.

The time had come for us to go down the spiral staircase to the basement workout area. He pointed towards the treadmill and instructed me to get warmed up with an eight-minute jog. He turned the machine up to a medium speed and went back upstairs.

Twelve minutes later, I was drenched in sweat, and there was no sign of Fabrice.

After what felt like an eternity, he came back downstairs and joked, "it's killing you!"

Fabrice explained that his paying clients undergo a series of tests in their first session. He measures their power, coordination, reaction speed, endurance, and muscle mass. Then he asks them exactly what they want to achieve.

"I am very results driven," he said, "I won't stop until they have reached their goals."

After the tests, Fabrice deduces a training schedule and diet plan for the customer. We skipped this and went straight into the HIIT (high-intensity interval training).

Fabrice demonstrated the first exercise: from a squatting position he crawled to the end of the mat and did a press up. He then crawled backwards into the squat and repeated.

It was my turn. The first 20 press-ups felt good, but I knew it was going to get a whole lot harder. He pointed towards the weights by the mirror.

Holding the dumbbells, I performed a series of squats, before lifting the weights above my head into a full extension. By the end of the 15 reps, it started to burn, so Fabrice offered some encouragement.

"You've got to tell yourself you've got this," he repeated, "You've got this."

When demonstrating the moves, Fabrice made everything look easy. Unlike many personal trainers, Fabrice doesn't use Instagram or YouTube to publicise himself.

"I don't have to have videos out there to prove anything," Fabrice said, "I just consider myself different."

Fabrice told me to perform one exercise after another, with only 10-second breaks in between.

"These are called supersets," he said. After completing a whole circuit of different intense exercises, which work similar muscle groups, I was allowed a slightly longer break of around 30 seconds.

I then repeated the circuit three times. This technique is intended to build muscle mass, as well as endurance.

Fabrice's clients visit him twice a week on average. However, sometimes they make more demanding requests. "Ninety-five percent of the goals I get are realistic," Fabrice said, "but I’ve had people say I want to lose 20 kilograms in seven days."

"I'm not a magician," he added.

One woman wanted Fabrice to train with her for four hours every day for two weeks. However, he turned it down. "I don't think that’s healthy," he said, "I don't think you can sustain that unless you're a top athlete."

Fabrice's talent is being able to motivate his clients to push themselves beyond what they are capable of on their own. He cites "mental strength" as the most important thing for those wanting to get fit.

"I can tell from the first conversation with someone if they are going to go the whole way and meet their goal or not," he said.

By the end of the third superset, my biceps had turned to jelly. I could no longer curl the bar towards my body. Fabrice came over to assist me, grabbing the bar with his strong arm and lifting it with me for the last few reps.

"You can do this," he said with a reassuring smile. "This is good for you."

At the time I believed him, but the next day I was unable to fully extend my right arm.

After I had repeated the circuit three times, Fabrice recognised that I could not do another.

"Let's take it easy," he said. "I don't want to kill you."

By this point, I found it hard to lift my arms above my head. So when Fabrice went to fetch the boxing gloves and a set of pads, he could sense my disapproval.

"This is fun," he said.

We sparred for a while, my gloves landing softly on his pads as he called out instructions. As it wore on, I found another wave of energy and began enjoying myself.

When we stopped, I felt a mixture of satisfaction and relief.

The hour I spent with Fabrice was undoubtedly very efficient exercise (my arms ached unbearably for the whole next day). However, having never used one before, I am unable to compare Fabrice to a £30-an-hour trainer from a local gym. I imagine the core principles are the same, but Fabrice is simply very good at what he does. So, due to the rules of supply and demand, some clients are willing to pay £1,000 for a one-hour session.

While this fee could buy a small car, a two-week holiday, or 40-months membership at a standard gym, for most of the people Fabrice works with, money is no object.

I asked him if he knows of any other trainer who charges £1,000 per hour.

"No," he said, "not anywhere in the world."