I rode my first half century yesterday (52.2 miles), and had some trouble with severe burning on my Quads, and some really bad cramping in a muscle just next to my knee. I started riding last July, and have been gradually working building mileage. I had ridden two 40 milers, one just two weeks ago. The burning started about 35 miles into the ride. As I hit 43 miles, I started a fairly steep climb, as I came out of the saddle, the muscles on the top-inside of my knee started twitching violently. I had to unclip and stop due to the pain and cramps. I pushed the bike to the top of the hill, waited 5 minutes and continued. Same problem on two subsequent climbs.
1) Is burning on the Quads normals and will it get better with more training?
2) What the heck was going on with the muscles around the knees?
3) Any suggestions on improving to eliminate these problems?