Yasso 800's

I have a new goal...to run a sub-2 hour half marathon.  I have decided to incorporate some speedwork into my running which will be easier now that I am back at the track a few days a week.  Last night was my first attempt at Yasso 800's. I know there are some who think it doesn't work, but for me I figure why not try.  The theory is that if a runner trains by running 800m intervals under a certain time their marathon/half marathon time will be a certain time.  Since I want to run a sub-2:00:00 half I need to run under 4 min 800m intervals. (I could get into how to figure it all out, but that might bore you!) Anyways I ran four intervals in under 4 min each last night.  I probably could have done another one, but decided to stick with just what the initial workout said to do.  It was not as difficult as I thought it would be although the thought of doing up to 10 is a little intimidating. :) If nothing else I needed something to change up my running and my legs could tell the difference this morning.  Not sure when I'll be able to run my next half, but I'll be anxious to see how this training theory works out!