USAIN BOLT – THE FASTEST MAN in the world. Never, ever do I get tired of hearing that. If you lined up a hundred people and asked them who the best basketball player in the world is, the best soccer player, or the best cricketer, it is unlikely they would provide the same answer. But ask any of them, “Who is the best sprinter in the world?” and there is only one answer – Usain Bolt. Why? Because that is what it says on the clock. There can be no dispute or argument. The record books say that over the 100 meters flat race, the true measure of human speed, I’m the fastest person that ever lived, completing the distance, as I did at the World Championships in Berlin, in 9.58 seconds.

It is said that the population of the earth is 6.8 billion and that approximately 107 billion have lived on this planet since man came into being. It doesn’t get any cooler than knowing you are the fastest of them all.

I chose to be a sprinter, not only because I was the fastest kid in school, but also because I knew that politics couldn’t interfere. In team sports it can be down to opinion whether you are the best. One coach might think you’re good enough for his team, another might not, or the side could be picked on friendship or family ties. But in athletics you are either the fastest or you aren’t – opinion doesn’t come into it.

We had a grass track at the front of Waldensia Primary School, which is still there, exactly as it was, with a two-foot dip at the end of the straight, and when I first raced on it a guy named Ricardo Geddes would beat me. One day the sports coach, Devere Nugent, bet me a lunch that I could beat Ricardo. I like my food, so it was a big incentive. I won, enjoyed a nice meal, and never lost to Ricardo again. Winning that race was my first experience of the thrill of beating your closest rival, and from that day on my motto has always been “Once I’ve beaten you, you won’t beat me again.” There was quite a sporting rivalry between me and Ricardo, and I told him he should keep going with athletics but, like most kids in Jamaica, he wanted to play football, which he still does for one of the clubs on the island.

Much as I loved football and cricket, running came so easy to me. Once I got Ricardo out of the way, I was the fastest, not only in school, but in the whole parish of Trelawny. And, after a few years in high school when I put my mind to training, I was the quickest junior in Jamaica, then the world.

As I went on to win gold medals and set world records at the Olympics and World Championships, I felt exactly the same about taking on my Jamaican teammate Asafa Powell and the Americans Wallace Spearmon and Tyson Gay as I did about racing against Ricardo Geddes. The aim was the same – to run as fast as you can and get to the line first, whether you are in the highly charged atmosphere of the 91,000-capacity Bird’s Nest stadium in Beijing or on the school field.

Just like at school, I always try to go faster and faster. When I clocked 9.72 seconds to set the world 100m record in New York, I knew I could do better; when I ran 9.69 to win gold at the Olympics, I knew there was a lot more to come; and now, having run 9.58 in Berlin, I believe I can go even faster.

It is possible for me to run 9.4. You can’t be sure when or where, but the major competitions are when I take it seriously and shine through. That’s business time, and I’m not going to let anyone take my titles away, so the World Championships in Korea in 2011 or the London Olympics in 2012 are where it will probably happen.

To get from 9.58 to 9.4 will involve a lot of hard work – it will have to be the perfect race from the start, through the drive phase, to making sure my focus is straight ahead and maintaining my form to the end. I’ve never been the best starter, but it’s improving, and I must stop looking from side to side, which is my worst habit. I lose time that way, but I can’t help it. My coach Glen Mills says he could cure the problem in an instant by putting blinkers on me like they do with racehorses.

There is always something that could be better. Even when I think a race has gone well, Coach will say “no” and take me back through it, pointing out the faults. If you run 9.58 you are entitled to think it all came together, but Coach tells me the drive phase out of the blocks was too short, I got too tight in the middle, and my head was all over the place, so there’s room for improvement.

I do believe there is a limit to how fast the human body can run, though, and I don’t see how the 100m record can ever go below 9.4. It is impossible to run 9.2, the body isn’t made to go that fast, no matter how hard you train, how good a shape you’re in or how good your technique.

As for the 200 meters, I don’t know what the limit is. My 19.30 in Beijing broke Michael Johnson’s record of 19.32, which had stood for 12 years. But I run the corner much more efficiently now, which is why I got the record down to 19.19 at the 2009 World Championships. I dream of being the first man to go under 19 seconds.

I was 24 in August 2010, and Coach says it will be at least two more years before I peak, maybe three. I’m nowhere near finished yet.