A bench squat is simply a squat to a bench. You quickly seat the bench with your ass at the bottom of your descent. This helps you recognize when you should power up through your heals to a standing position, making it an excellent form reminder. You're likely to gain more depth than another person doing a regular squat without a bench.
LOWER BODY FOCUS
This exercise focuses heavily on the lower body. It requires a squat rack, squat bar, whatever weight your Sally Ass can handle, a bench, and recommended Weight belt and knee sleeves. Use bench squats to sharpen your form, especially if you've recently increased your lifting weight or need a reminder of how deep you should be going.
IT AINT EASY
Don't let anybody fool you. Using the seat does not make you a Sissy. If doing it properly, it tends to be more difficult than a regular squat. The bench is a physical reminder of your range of motion. Use controlled motion to bring your firm and tight booty to the bench . . . do not flop down on it, this will not help your form. If you find yourself losing control of the bottom motion, you are using too much weight.
ITS ALL IN THE HIPS . . . not really
Form is essential with this squat. The bench squat helps you with finding and fine tuning your form, when done correctly. Engage your core, roll your shoulder blades back and down (check video for bar placement, not too high, not too low, meaty part of the shoulders). Ensure your back is straight (weight belt will help with this), do not hunch forward on descent or in the lift. When descending, push your rock hard glutes out while supporting the weight on your thighs. Do not bow forward, that is how you f@ck up your back.
When you reach the bench, your thighs should be parallel to the floor. Look down, ensure your knees are behind your toes (this will keep you from f@cking those things up too). Once you reach the bench, fire upwards through your heals, keep back straight on the way up, do not lock out your knees at the pinnacle of the lift.