I only started this whole pesky running thing as my company hold a Duathlon each year. As I've been a pretty OK cyclist I thought I should have a go, and to that intent I started running in April in preparation for the event in September.
Total running distance was only 5k split into two, before and after the bike.
It was good to aim for, because I had a realistic chance of doing well if I'd train for it. So this forced me to train quite intensively. Each session brought me faster times, and I was quietly confident on the day. Wasn;t sure about the running though, so I hid in the middle of the pack until I thought I could make a break for the end of the first run. This I did, and dropped everyone. Cocked up my transition though, and then had to catch people on the bike - which was OK. Then I just had to stay ahead on the last run of a pretty serious Triathlete on my tail. I did it though - I was in all sorts of pain at the finish and couldn't walk for a week, but it was worthwhile.
Hardly Olympic Standard, but I felt good about it !