Well, I'm not an expert by any means, but I always thought lunges worked the hammies, quads, and glutes. So I searched a little and found this:

http://www.bodybuildbid.com/article...amstrings2.html

I also do the same if I overestimate how much weight to use, I lower it so I can do it, I don't see the point of flat out stopping either or pushing yourself too far. Looks like you had another great workout!