Box squats, which involve squatting down on a box or bench placed behind you, are an effective method for increasing your strength on the regular squat.
Scientists at Appalachian State University (Boone, North Carolina) tested the muscle power and force production of trained male lifters when they did a regular squat or a box squat.
The researchers reported in a recent issue of the Journal of Strength & Conditioning Research that when the men did the box squat, they produced more muscle force and power than when they did a regular squat.
Many powerlifters have used box squats to boost their squat strength. Apparently, box squats help to do this because, as shown in that experiment, they allow the lifter to squat with more force (i.e., strength) and power.
Consider using box squats from time-to-time on leg day so that you’ll be able to drive up more weight on your regular squat. To do this, place a box — or use a flat bench in a rack — that, when you sit on it, allows your quads to be parallel with the floor. Squat back onto it, but as soon as your glutes touch down, reverse the direction to drive back up to a standing position. Do not sit down all the way, as this can place a lot of stress on your spine due to the weight you are supporting on your shoulders. Box squats, because they teach you how to properly sit back into a squat, will also help perfect your form on the squat.