Olympic marathon champion Eliud Kipchoge is currently the undisputed world No.1 over the 26.2-mile distance.
Here the two-time Berlin and London Marathon winner explains why he runs.
“I started running because my neighbour, Patrick Sang (the 1992 Olympic and 1991 and 1993 world steeplechase silver medallist), was an athlete and I wanted to be just like him.
“Patrick came from the same village as I do and my mother used to be his teacher. I was so inspired by his success.
“While preparing for the Kenyan Championships, I wrote a letter to Patrick asking if he could write a training programme for me.
“He did so without knowing me that well and that is when my running journey really started.
“Today Patrick is still my coach — although nowadays he is far more than an athletics coach. He is also a life coach and a business coach and that’s what sets him apart from other coaches.
“One of my first races came over 10km in 2002. I won that race and it felt great. I would say that is when I first fell in love with running. Now when I miss a day’s running, it makes me feel bad. It’s like when I was younger and I missed a day at school.
“To me, running is life. I run to live longer and enjoy a healthier life.
I always say: a run in the morning is like eating a fruit a day – it chases the doctor away. It is good for your mind.
“Running has given me so much. It has allowed me to travel the world and enjoy a good lifestyle in general. I am always happy training, racing and above all, of course, when I win.
“That is the most enjoyable part to running. It gives me energy and motivation to target the next victory.
“People ask me why I run. It is for life and to inspire the younger generation to love sport and live a happy and full life. I can’t imagine a life without running.” [IAAF]