I am sitting in a quadruple scull – a four-person, eight-oared rowing boat – behind an Olympic hopeful and in front of a reigning world champion, and I am about to row for the first time in my life.

In the boat with me are Leander club athletes Tina Stiller, Kieran Emery and Tom Clark. All will miss out on London 2012, but have their sights set on gold at Rio de Janeiro in 2016. Stiller, a reserve at the Beijing Olympics, is sitting out this year through injury, as is last year's lightweight world champion Emery, while young heavyweight Clark will soon be ready for the senior squad. All are used to having team-mates a lot more experienced than me.

Leander is one of the world's oldest surviving rowing clubs, founded in 1818 and flourishing today as much as ever. This year, Leander club athletes will make up half of Team GB, and in the past it has been home to such heroes of the sport as Sir Matthew Pinsent and Sir Steve Redgrave. The club's Olympic medal haul stands at 99, and, barring a string of disasters, that number looks sure to pass 100 this summer.

Its continued success is the product of a rigorous and gruelling schedule. Athletes with the club train seven days a week for 11 months a year, taking the day off only every third Sunday. Such intense exercise demands that they eat almost constantly. "We train three times a day," explains Emery. "We have breakfast, you're in the gym by 7.30, do 18k, then come in and have a second breakfast." Heavyweight men at the club, Clark tells me, eat between 6,000 and 7,000 calories a day.

Yet for all the physical strength it requires, when we push off from the bank and begin to row, what strikes me is not how tiring it is but how stressful. I have had 10 minutes of practice on an ergometer (rowing machine), and had felt I was close to getting the hang of it. But in the boat, with real oars, water and other rowers to try to fall in sync with, I "catch a crab" within seconds.

The journey out flays my nerves: even when I'm not catching a crab, I keep scraping my hands against each other, and can't get in sync with the others for more than a single stroke at a time. As a beginner, it's clear that technique is more important than thick thighs and rippling biceps.

Rowing is a full-body workout, burning calories while toning just about every major muscle. It's good for the mind, too: "Rowing is a good sport for people with attention deficit disorder", says volunteer coach and committee member, Jeremy Moore. "Because of the concentration it requires."

At Leander, psychological training is Moore's responsibility. Most of his other work for the club is as a businessman: last year he secured its financial future with a sponsorship deal from clothing brand Gant. But about a month before a major race, he begins to coach crews on their mindset. There are, he says, two vital mental qualities. The first is willpower, or as Moore puts it: "Can I hurt myself more than you can hurt you?" The best recent example of this philosophy being Oxford rower Alex Woods, who had to be rushed to hospital by paramedics after collapsing at the end of this year's eventful Boat Race. "It's very common for people to collapse in rowing," explains Moore, "because they are racing to destruction." It's a sport, in short, for masochists. As Emery tells me: "You've got to enjoy the pain."

Alongside willpower, the other crucial quality is concentration. The key to which, says Moore, is the heart. He demonstrates this point in the club room by wiring me up to a heart-rate monitor and then asking me to sing Madonna's Like A Virgin in front of everyone at the top of my lungs. At the mere thought, my heart rate skyrockets, and on the screen I watch as I go into what Moore calls "cardiac chaos", in which coordination skills plummet and even just speaking becomes a struggle. "If you go into cardiac chaos your brain closes down," he explains. "Think of the heart as like tuning a radio." The key is to breathe deeply and stay calm.

Out on the river, after a panicked first five minutes, we turn to head back and Moore – who has been following us on the motorised launch – reminds me to remember to breathe. On the return journey, breathing deeply and doing my best to be relaxed, I'm surprised to find I can fall into sync with the others for six or seven strokes at a time, and we make it back to the boathouse without catching a single crab. "You did well," says Stiller, as we clamber out and carry the boat in to dry.

I make a doubtful face, but she insists. "Your hands aren't bleeding. That means you did well."