A bit over two years ago when I first started riding (and riding too much), my quads certainly got larger. Then I was off the bike on and off due to a few injuries and lost some of that. This year when I regained my lower-body strength my quads seem to be growing harder rather than larger - and much more calf muscle definition. My legs look like sticks unless you really start looking at them, but I've a very strong lower body. I guess things change - or else my workouts are different enough this year that my legs are developing differently? I don't know, but it is interesting.