You wouldn't run a marathon the day before you run a marathon, you need to leave some sort of surprise for your body.

There's a balance and I feel very, very strong and very, very fit at the moment. There's no - touch wood - niggles at the moment, there's nothing that's twinging or nothing that's too painful. Apart from a bit of chafing from the wetsuit!

Also it'll be unbelievably cold in there and the thing I'm probably most worried about is my face. That sounds silly but it's very difficult, if you're in cold temperature water, to get your head under because it takes your breath away. And then your hands go numb so you try and wriggle your fingers while swimming to warm up. It's very tough.

I just have to deal with it [injuries] if and when problems happen. It's obviously a concern and I've been very careful with my training, making sure I warm up and warm down before everything and not pushing myself too stupidly.

At the end of October I started doing a bit more swimming and learning how to swim properly, because I hadn't really done it since I was at school. Then I really accelerated in December and for the whole of January's I've been doing at least one thing a day - normally a swim and a cycle, or a swim and a run, every single day.