I was just curious if any of you do fartleks on long runs? For those who do not know what they are, that question could sound extremely funny as the kid in me always laughs when I say that word. I have been working to shave my half-marathon time down and I've trimmed 4minutes off it (previous PR was 2:01 and is now 1:57) doing that. I make myself keep all miles under 9 minutes and then start doing them if I ever get over 9mm for 30 seconds every 2 minutes. I listen to Pandora when running so anytime a commercial comes on, I do a fartlek regardless of my pace.