I don't know what I've done but it started twinging as soon as I began walking in my trainers, and from the first footfall of running it started hurting, getting worse until I couldn't run on it at all. I wonder if it's my trainers ... they're not running shoes by any means, they're very battered and worn old baseball-boot-style HiTecs that I've had for years. I know they're not ideal, but I wasn't going to get "proper" running shoes until I know whether I can actually stick out this running lark.

I'm gutted, I was just beginning to think I could actually do this, and now I have to stop until I can figure out what's causing the pain - and stop it!