I do not have a lot of experience with box squats, as I have never felt the need to do them. From my understanding, most feel that the quad is limited in the box squat. I honestly feel a lot of it is dependent on your stance. I am a very quad dominate squatter, and prefer a tighter stance. If you are looking at getting in more quad work from squatting, my suggestion is to bring your stance just inside your shoulders, keep your toes out, and bring your squats DEEP.
Best meet lifts: 1040squat, 730 bench, 730 deadlift
Best total: 1040-680-730=2450
"This is about strength, not getting a 10.0 form score from the Russian judge" Steve Shaw