20 years ago, box squatting was a staple for powerlifters, especially equipped powerlifting as Louie Simmons popularized it. There are countless articles written on box squats, variations and how to implement them in different ways.
My main goal with this post is to give box squatting technique on the ground level for new lifters and general population folks. Remember that the ultimate goal of squatting is to keep the bar/shoulders centered over the foot, while ideally keeping the hips and spine in a good position for efficient and safe movement. Without going down the rabbit hole of different limb lengths, genetic builds, etc, we are just going to touch on these 3 basic points.
1. Pressure the entire foot into the ground. Beginner lifters and new people need to understand the basics of how the foot applies force to the ground. Don't confuse that with sitting back on their heels or leaning forward on the toes. Just get them to understand entire foot contact.
2. Soft touch and slight pause on the box. We don't want them falling to the box, but not bouncing off the box either. Teaching them a soft touch and slight pause builds eccentric control and body awareness to where they are in space and what they are feeling.
3. Maintaining torso position while on the box. This concept ties in strongly to #2 as well. Don't teach them back habits like rocking back or overly arching the low back. They also shouldn't be leaning or rocking forward to get off the box. (Yes, strength is an indicator of how well they can transition from sit to stand, but that's why choosing the right size box is key.)
With newer lifters, the goal in box squatting is to clean up any major technique flaws. But it should eventually lead to being able to squatting proficiently without the box. When you teach a box squat that is completely different than a regular squat, you'll not only confuse them when you take the box away, but you may create poor habits down the road.
Beginner lifters and those new to the gym thrive on things they understand and can accomplish. Show them success in one area and they build confidence in others. As an example, I have a client who started with me at 350 pounds. Her knee hurt and we started squatting to a 24" box. She can now squat pain free to an 18" box (she's tall) and can free squat just as well! (Oh and she's also lost 60 pounds!) Her success in the squats in the beginning led to building her confidence in other areas in and out of the gym. She's hooked and loving her new lifestyle!