In my Olympic history I don't think I have achieved my potential as an athlete. That's what I want when I look back at my career. I want to be able to say I gave it my best shot.

Never set limits, go after your dreams, don't be afraid to push the boundaries. And laugh a lot - it's good for you!

The cheats always have a way of justifying their behaviour - everyone else is getting away with it, so why shouldn't I? But because they're so reliant on the drugs - and the drugs are not always perfect, you're not guaranteed to peak at a big event - they don't have the confidence to look in the mirror and know that they can go out and give their best. If you're clean and you've prepared well for a race, that's where you have an edge.

I can't imagine living and not running.

As an athlete, there are advantages being with a team and getting regular physio...

At big championships it's not the fastest person, it's the person who gets it right on the day.

Plenty of people who are 38 have run really well in the marathon.