Of all the things to fall into, I didn't think I'd fall into a marathon. Usually, you use this term to describe something fairly massive. What I'd actually intended was different, so I can say I fell into the marathon, though I can't say it felt so big. It's only retrospectively I realised that, had my name been Pheidippides, I should, by rights, be dead now.

Anyway, the story was this. I arranged "last minute" with my sister, to go and play on our bikes. By "last minute", we actually mean with over 24 hours' notice, but it's all relative, I suppose. By "play on our bikes", I mean that my sister has a new bike, and I offered to come along, have a peep at it and then go for a ride together as a bit of a laugh.

In truth, I'd thought that this might be one "sport" I could comfortably hold my own with in the same space as my sister. She's improved her fitness levels considerably and is always quite competitive (or maybe I am when I'm with her and blaming it on her - either way). Anyway, I had planned to arrive at hers mainly on public transport, avoiding the 8 mile trek from Paddington to her house, which would lose me the edge.

I won't really have to explain much more beyond the fact that the London transport system abhors people's bikes and the rest is obvious. I cycled to her house, tackling the one daunting Highgate Hill as an optional detour on the way to my destination. It was still hard work, but I relished every push, because I could do it.

I arrived, had a quick drink and then we knocked out a few miles together. I ended up cycling back and then getting off the train and pushing myself to the 26 mile mark (pretty much) as I got home. As it happens, I was still going strong at 26 miles. It's not that far on the bike.

I was burning off a fair bit of energy, though.