You probably should warm up like this before some of your runs, at least. Has it effected any O races this year?
All of them to some extent, although less than when I run from home because I do at least do a bit of warm up and/or jog to the start. Had we been doing the British/JK I might have bothered to do a full 20 mins. It has to be at a reasonable speed though, and adding 2 miles to each of the JK days might have been worse than just putting up with it.
Right, yeah. I was thinking 20mins might take some of the speed from the legs