Just wondering what everyone's thoughts are on how much weight training you do if you also tend to run/bike/interval train a lot. I find that doing these other activities keeps my legs strong and muscular, and thus I have a reduced need to do weights for my legs as compared to doing upper body. I also hate doing a heavy leg day and being left sore when I'm about to do another run or bike ride. It seems that heavy leg weight training and running/biking don't mix well together. The only thing I would add is that at least in my case, I do not feel that my muscular development between my lower and upper body is disproportionate.

actually, running and other cardio like that cant be considered strenght training for the legs. because cardio is a light load on the legs over a long time. while strenght training requires a heavy load.