London Marathon 2013: taster is crucial part of a painful learning curve for Olympic champion Mo Farah In a marathon it's not like that. You might get pain in your calves and in other parts of your body. I don't know where the pain will be. It's all a learning curve, but that's why you need a great coach, physiologist and nutritionist. There is no doubting his coach's credentials as an expert in marathon running. Alberto Salazar, the American who is credited with turning Farah into a world-beater since welcoming him into his Portland training group in 2011, was himself a 26-mile specialist who won three consecutive New York Marathon titles from 1980 to 1982. He is also a man who preaches caution when it comes to injury prevention, which is why a proportion of Farah's training mileage is performed on an underwater treadmill to reduce the amount of high-impact pounding on his body. It is unlikely that he will force sudden changes on Farah when he begins his London Marathon preparations in September. The transition will be managed as smoothly as possible as he adjusts to the demands of carrying tired and heavy legs for longer intervals. It helps there is already another marathon runner in Salazar's group, American Dathan Ritzenhein, who has a personal best of 2hr 7min 47sec. He will take over from Galan Rupp as Farah's main training partner in Portland. Apart from the physical challenges, Farah says he also needs to learn about the event, which is why he took up the offer of London organisers to run the first half of Sunday's race. The key to running 26.2 miles, he says, is knowing how to conserve energy. "It's something I have to learn," he said. If you look back when I was younger, even in 2005, in every race I would go early and people would kick past me. It's all about learning. I've got to sit back and relax. My training partner, Micah Kogo, who was second in Boston, didn't make any mistakes. He just sat back, sat back, sat back. He didn't push the race. That's something you have to learn. Save your energy, stay relaxed, stay positive and just think about how your body feels. Farah's problem is that his marathon opponents will be doing everything in their power to drain his energy, knowing that they would not be able to live with his sprint speed if it came down to a final kick. Farah is well aware that he will be a marked man. People who have seen me on the circuit know what I'm capable of. If you know someone's weapon, you know what they are going to do, so you shield yourself. What they will do probably is take it out early and work, work, work the kick out of me. I'm sure that's what they'll do. We will have to wait until next year to discover whether they will be successful. It promises to be one of the most fascinating London Marathons in years.