As I am only just beginning Week 4 of C25K, it might seem a bit odd that I'm dishing out advice already. But I used to run quite a bit - albeit slowly and sporadically - and I have completed a couple of half marathons, the last one in 2011. The reason I had to stop was because my lower back, hips and large muscles at the top of my bottom pretty much seized up. The cause? Years of insufficient stretching, being to 'busy' to stretch properly after my runs. And when I was younger, I got away with it. Once I hit my 50s (I am now 54) all those chickens came home to roost.
So, please, if you want to carry on running happily and safely for years to come, make time to stretch properly afterwards. I really wish now that I had run for maybe 10 minutes less and used that time to stretch properly. If I had I wouldn't be starting from scratch now, always aware that I can set off my problems again unless I stretch religiously every single day. I notice that Laura tells you to have a drink and a piece of fruit after a run. She doesn't mention stretching, not at this stage anyway. But do it anyway - I promise it will be worth it.