Belt squats have been popularized quite a bit as of late with good reason. When preformed correctly they are a great tool to utilize in your or your athletes’ training.
The loading pin strapped around the waist automatically places the weight over the mid foot and greatly reduces the need for forward lean. This allows more of the weight to shift on to the quads. In addition, this set up also does not load the spine; a great benefit to the injured or over taxed athlete. When enough weight is used a belt squat can create a traction effect on the spine for which I can attest that I personally have received quite a bit of benefit from(think inversion table feeling).
It’s important to maintain a good position while doing belt squats. Do not allow the weight to pull you into the bottom causing your lower back to tuck under your pelvis. The whole point of belt squats is to keep your back healthy. Stay up right, keep decent tempo on your decent, and watch your quads blow up.