Doctors and scientists said breaking the four-minute mile was impossible, that one would die in the attempt. Thus, when I got up from the track after collapsing at the finish line, I figured I was dead

It is a paradox to say the human body has no 'limit.' There must be a limit to the speed at which men can run. I feel this may be around 3:30 for the mile. However, another paradox remains - if an athlete manages to run 3:30, another runner could be found to marginally improve on that time.

You get very tired, and there was a certain amount of pain and you slow up. Your legs are so tired that you are in fact slowing. If you don't keep running, keep your blood circulating, the muscles stop pumping the blood back and you get dizzy.

Every time I ran the mile I was aware of my own weakness, there was some opponent who could give me a hell of a fight, so I never went into a race with a sense of invincibility. I always had that feeling of fragility and nerves which made me run faster.

Whether we athletes liked it or not, the 4-minute mile had become rather like an Everest: a challenge to the human spirit, it was a barrier that seemed to defy all attempts to break it, an irksome reminder that men's striving might be in vain.

Just because they say it's impossible doesn't mean you can't do it.

It's a question of spreading the available energy, aerobic and anaerobic, evenly over four minutes. If you run one part too fast, you pay a price. If you run another part more slowly your overall time is slower.