Iten is an unlikely runners' paradise. High up in Kenya's Rift Valley, it's a small, chaotic town, typical of the region. The mitumba (secondhand clothes market) spills out by the side of the only tarmac road, as matatus (small buses) drive by day and night, beeping and touting for passengers. Donkeys and cyclists struggle by piled high with crates of chickens or sacks of charcoal, and sheep, goats and cows roam freely.
The surrounding countryside is dotted with round mud huts; in hand-ploughed fields, children in torn clothes stand and stare, and dusty roads crisscross the fertile land in every direction. It is along these roads, usually early in the morning, that you will find the runners. One after the other after the other they shoot by, dressed in Lycra, the latest Nike running shoes and Gore-Tex jackets. It's an incongruous sight, but to an athletics fan, it makes perfect sense. Because from this tiny corner of Kenya hail most of the world's greatest distance runners.
Lacing up your trainers and heading out for a run in Iten is a daunting experience. There don't appear to be any joggers. Every single person is fast. Even the other foreign runners who gather here are all international athletes. Luckily, I'm staying in Iten as part of a group – the only one, it seems – of non-elite runners. There are seven of us, ranging from someone hoping to run a half-marathon in two hours, to someone hoping to run a full marathon in precisely two hours, 24 minutes.
We're in Iten as part of the Kenya Experience, a holiday for runners recently set up by English couple Gavin and Lauren Smith. A budding coach, Gavin knows the town and the Kenyan runners well. He regularly points out the various Olympic champions and world record holders we pass as we're running or walking around.
"That's the steeplechase world record holder," says Gavin, as a group of runners, including Saif Saaeed Shaheen, charge past. "The one with the yellow shoes." There goes the women's world half-marathon record holder, Mary Keitany, on the other side of the road.
Gavin gives us all a personal training plan when we arrive and offers to take us out for runs, or – if we're brave enough – to find Kenyan athletes for us to run with. Although I like to think of myself as a fairly decent runner (my half-marathon time is one hour, 26 minutes), heading out with the Kenyans is a hair-raising experience.
With another member of our group (the two-hour, 24-minute marathon hopeful), I join up for a Kenyan fartlek session – which is basically a long run with fast bits and slow bits. From our base at the High Altitude Training Camp (HATC), owned by former world half-marathon record holder Lornah Kiplagat, it's a 20-minute jog just to the starting point. At the bottom of a long hill, by a bridge over a stream, we find a group of about 200 athletes, milling around and stretching. One man stands up on a mound like a preacher and explains what happens in the session. Spotting us in the crowd, he repeats the instructions in English. I give him the thumbs-up, to much mirth and giggling among the other runners.
The plan is to run gently for one minute and then hard for two minutes. And then to repeat that pattern 17 times. I don't have a watch, but after a minute of jogging, a swarm of beeping watches tells me it's time to go hard. It's uphill, hot and we're running at 2,400m – those are my excuses anyway, because almost instantly I'm drifting backwards, like something heavy falling through water.
People ping by on both sides until I'm watching the main group disappear into the distance. Fortunately, though, I'm not the only straggler, and I manage to keep pace with the backmarkers until the end. The final stretch takes us up a ridiculous hill that has me almost walking.
Afterwards, the Kenyans are smiling and friendly, telling me I did well. All the runners here are welcoming, with no one apparently concerned that I'm like a tortoise to their hares.
When we're not running, we lounge around the upmarket facilities at the HATC. The place is crawling with international athletes, including six top British middle-distance runners. The camp has a lovely swimming pool, although as it's the rainy season, the air temperature is a little too cool to make the water irresistible.
One day we get to visit a typical Kenyan training camp, which is more than a few notches down on the comfort stakes. Here, the athletes sleep in tiny dormitories, and their food is cooked over a wood fire in a kitchen that's a corrugated iron shack. The camp houses about 10 Kenyan athletes and top British marathon runner Tom Payn. He seems to be enjoying life in the camp, despite the basic conditions, although he does say that the one thing he misses is a sit-down toilet.
Gavin and Lauren have arranged a packed schedule of visits and activities for us, some of which work better than others. We visit Iten's famous St Patrick's High School, which has produced dozens of Olympic and world champions and world record holders. Along one wall in the dining room, where beans are being dished out of huge vats for lunch, is the school's wall of fame. Among the star names are the former world 800m record holder and three times world champion Wilson Kipketer, and the 2010 IAAF world athlete of the year, David Rudisha, who still lives and trains on the school campus. Unfortunately, he's away competing in Australia when we visit.
One famous runner we do meet is former world 10,000m champion Moses Tanui, who comes to give us a talk. He spends most of the time telling us why Kenyan runners are not as good as they should be, as torrents of rain batter the tin roof outside, making it hard to hear his soft spoken voice.
By the end of two weeks, we have had a taste of life in Kenya's cradle of champions. It's a mad, bustling place, full of warm, welcoming smiles. Everyone is sad to leave, but thanks to Gavin's training programme and the high altitude, we're all going home fitter than we arrived.
Read Adharanand Finn's running blog at guardian.co.uk
