I use a wide variety of box heights with my athletes. The boxes I use vary from 6” from the floor to 2” above parallel. I cycle the different box heights with my athletes. Remember that doing the same thing all of the time gets you the same results! For example, in the initial stages of the off-season for my basketball and volleyball players, I usually have them perform box squats and regular squats below parallel. This is because their sport dictates that they are usually going through a partial range of motion with their squat depth during competition. During the initial stages of the off-season, I try to overcome the imbalances that they have created by performing full-range squats. This helps to create a healthier knee joint.
As the season approaches, I may make the squats more “specific” by performing squat variations that mimic the jumping motion"