A surprise

I started my run today without my watch but with Endo running without the audio coach. I went out by feel and ran at a comfortable pace. I didn't know how fast I was running until I hit the 3 mile turnaround. (I was feeling so good this afternoon that I decided to run 6 miles instead of the 4 I was planning). I ran strong and ended up with a good time on the 6 miles. But my quads were sore the whole time and my legs felt heavy. Again, a surprise that I ran so well. I even had a super kick for the last 1/4 mile, about 7:00 pace. It felt awesome to drop the hammer and feel like I was flying for that last little bit.  I think I need to do some tempo runs, which could feel similar.