Standing on a small suburban street in Teddington, south-west London, at 8am on a Tuesday morning, I check the details again. It's definitely number 18, opposite the Tesco car park: an unassuming, 1960s terraced house with grey blinds pulled across the windows. Weeds are coming up through cracks in the concrete parking spot in the front. Bins and recycling boxes are lined up under the window, which hasn't been cleaned for a while. The door is set back into the wall, so I have to venture into the dimness of the brick doorway to ring the bell. I wait for a few minutes, stepping back out to the quiet street, but there is no answer. I try it again. After another few minutes, the door opens slowly. A slim man in a tracksuit opens it and looks at me with sleepy eyes. I explain who I am, hoping that he's expecting me. He nods and lets me in.
Inside he takes me upstairs to an untidy living-room and spends about five minutes absently pointing the remote control at the TV before it finally turns on. He doesn't say anything other than that his name is Micah. Once the TV is on, he turns and leaves the room. '
Micah is Micah Kogo, the world-record holder for 10km on the road; bronze medallist behind the great Kenenisa Bekele at the Beijing Olympics. He has gone off to get changed. We are going to go for a run together.
Heads appear intermittently in the doorway behind me as I sit in my running kit watching Sky News. There are six Kenyan athletes currently living in the house, and they seem to be finding my presence quite amusing. I can hear them talking to each other in the landing. Eventually Enda, the house organiser, turns up and introduces me to everyone. They offer me limp handshakes and smile at each other as I'm told who has broken which world record, or won which world championship event. (Kenyan runners have won an incredible 46 Olympic and World Championship gold medals since 1987, all in the middle- and long-distance events.)
Enda, a student from Ireland who does this as a summer job, has arrived with top US steeplechase runner Steve Slattery, who is going to join us all on the run. I'm psyched up, wearing my fastest running gear. I like to think I'm a fairly good runner – I even won a 10km road race in Devon last year – but these are the Kenyans. The runners you see tearing away at the front in the Olympics, leaving everyone else panting hopelessly five laps behind. Micah's 10km road world record is 27 minutes. My best time is just under 39 minutes.
They all wear full tracksuits despite the muggy heat as we head out through the small back garden, a couple of bikes leaning up against the fence, the old bulldog next door barking at us hoarsely. We walk to the end of a small cul-de-sac then to the main road. They talk and joke with Enda about their recent races. I'm ready to roll, but nobody seems to be in a hurry to actually start running. Bethwell Birgen, a young 1,500m runner, explains to me that they don't like to run on Tarmac, so they always walk until they get to the park.
The nearby Bushy Park is a large expanse of flat grassland, complete with deer and a maze of gravel pathways and tracks perfect for running. It is one of the reasons the Kenyans use this particular corner of the world for their home while they're away from Kenya. Most of the big races, particularly in the summer, are in Europe. Teddington is near Heathrow, and it has the park and also a running track close by. As we walk, a group of top Australian athletes runs past. Later, on the track, we see Stephanie Twell, one of Britain's brightest young talents. "This place is a Mecca for running," Enda tells me.
Once we get to the park, there is a lot of standing around and talking, and some half-hearted stretching. Steve warns me that the Kenyans will probably try to race him. "They hate to get beat by an American," he says. And then, without warning, we're off.
The pace is surprisingly easy, and I find I can keep up without too much trouble. I'm secretly hoping people will look at us in wonder as we run past. Wow, look, Kenyans. And did you see that white guy? He must be some runner. But the park is virtually empty save for a few dog-walkers, who don't even give us a second glance.
After about two miles, Mike Kigen, a former Kenyan 5,000m champion, Steve, and Vivian Cheruiyot, the current women's world 5,000m champion, all suddenly speed up. None of them says anything; it just seems to happen. Within seconds, like startled animals, they're gone, their heads bobbing away into the distance. The rest of us keep an easy pace (at least, it's easy for the Kenyan athletes) until we've run around half the park and back to where we started. The others are already there waiting for us, having run around the whole park. "I told you they'd race me," says Steve.
Back at the house, Micah heats up some Kenyan chapattis for me for breakfast. He tells me about the day he broke the world record. He says he remembers warming up and feeling light, but strong. "So light, but so strong," he says, almost reverential of the memory. All the athletes perk up when they talk about running. Vivian, a tiny woman who can't weigh more that six stone, tells me about the day she won the world championships, beating the supposedly unbeatable Ethiopians. "It was so much fun," she says, grinning.
It seems amazing to be sitting in this simple kitchen in Teddington talking about these things. While the house is clean and does everything the athletes need it to, I'm surprised that such sporting superstars are not living somewhere more luxurious. The only shower cubicle is half the size of my own at home, while the décor and furnishings remind me of a hostel or student house. The athletes share bedrooms, while the sitting-room is filled with two large, tatty blue sofas, a giant TV and piles of video cassettes. Here in the kitchen the walls are bare, save for a small picture of a Cuban street scene hung lopsided over the top of a noticeboard. Printed on the board is a phone number for taxis to the airport, instructions about opening windows to let fresh air circulate, and a warning not to take any medication without consulting the office.
The office in question belongs to Pace Sports Management, one of the world's leading athlete-management companies. It runs one of the top training camps in Kenya, where it signs up the most talented athletes, helps train them and then arranges their appearances at races around the world in return for a percentage of any prize money. The house in Teddington belongs to Pace.
The athletes seem content with the set-up. They all appear to get on well with each other and spend the day when they're not training either sleeping, being massaged or watching television. Do they ever go out, to a restaurant, the cinema or anything? Micah looks at me blankly as though such an idea has never crossed his mind. "No," he says.
When they get fed up sleeping and channel-surfing – Mike seems to be mostly in charge of the remote, flicking through the channels at a dizzying rate – they watch videos. Apparently they like kung-fu movies, but today they've put on a flickering documentary narrated by Sebastian Coe about the 1996 athletics season.
Without a doubt, this house is for them a transitory place, a base rather than a home. Their real home is back in Kenya, where many of them own farms, and have wives, husbands and children. "Do you miss them?" I ask. Again they look at me blankly. There seems to be a calm acceptance about what they do. They know they are the lucky ones to have the talent to run.
"In Kenya," Richard Kiplagat, an 800m specialist, explains, "there is always someone new, someone faster coming through. The career of an athlete can be short. You have to make the most of your time while you can." If they do earn much money – and some of them do – it obviously all goes back to Kenya. They have little to spend money on here; although Mike says he is keen to buy a tool for trimming back his trees in Kenya. And when we get back from the track, all the men get very excited about a brand new Jaguar car parked outside the house, walking around it and peering admiringly through the windows.
The athletes use some of their money to help younger runners back home. Richard tells me he has three "boys" living at his house in the town of Eldoret. They are all up-and-coming runners whom he sponsors so they don't have to work. When he goes home, they act as his training partners.
The spirit of co-operation that exists between the Kenyan athletes is evident during the track session they do before lunch. Micah, Mike and Bethwell take turns to lead each other through a series of 300m sprints. Enda meets us at the track, which is part of St Mary's University College. He times the intervals, offering encouragement and chastising the athletes when the pace slows a little. They take it in good spirits but it seems odd for a student from Ireland to be coaching these great athletes. "They all already know what they're doing," Enda explains. But everyone needs a little encouragement from time to time.
The track session is the day's serious running, so I sit and watch as they hurtle around in the soft drizzle that has set in. It's an incongruous scene; three Kenyans running in full flight as students wander past on their way to lectures, the sprinkler going tac-tac-tac on the rugby pitches behind the track. Richard, who isn't training as he has a race in a few days, turns up to watch and starts taking pictures with his new camera. He says he wants one with me, so we stand with arms around each other as Enda takes the picture. He's just like any other 26-year-old on a foreign adventure, taking pictures to show his family back home.
Sitting in the Teddington living-room later, I feel like I've been transported back to my university days, when we had endless time to hang out with friends, chatting, watching TV. There's even a cooking and washing-up rota in the house, although Micah seems to do most of the cooking. He's downstairs now, preparing ugali for lunch. Ugali is a traditional African dish of maize flour cooked with water until it forms a dough, which is then sliced with a bread knife and eaten with vegetables and chicken. They eat ugali every day and only half-jokingly claim it is the secret to Kenya's incredible running success. I consult nutritionist Surinder Phull, who says that is unlikely. "It certainly isn't a miracle superfood," she says. "It's just starchy carbs, which are important for running, but it isn't particularly rich in nutrients."
Later that evening, after they have all slept and been massaged, Richard, Vivian and Gladys Chemweno, a cross-country and 10km runner, head out for another session. They seem surprised that I want to join them again, but it's not every day I get to train with such great runners. The walk to the park is again unhurried, slower than people in London usually walk. For such fast runners, they seem to do everything else incredibly slowly. Along the way they gossip loudly about friends back in Kenya, or at least that's what they tell me – they're talking in their Kalenjin language. Vivian is so engrossed in one story that she gets startled suddenly by a branch overhanging the path.
"I thought it was a chameleon," she explains to me after much shrieking and laughter.
The chatter continues throughout the run, which is done at such a slow pace even I find it easy. It's as though they've just come out for some fresh air and something to do.
I leave them a few hours later, sitting in their living-room in the dimming evening light watching a Charles Bronson movie. Outside, the streetlights have come on. A man with a briefcase is walking home after a day at the office. People are getting into cars with their shopping in the Tesco car park, or heading out to the pub, while inside number 18, six of the world's best runners lounge on their sofas, almost ready for bed.
'Running with the Kenyans' by Adharanand Finn will be published by Faber in 2012. Most of the runners featured in this article hope to be running at the Aviva London Grand Prix at Crystal Palace, 13-14 August, avivaathletics.co.uk