Unrack the loaded barbell and place it on your back resting on your traps and shoulder. Hold it firmly in place and make sure your feet are wider than your shoulder width. This is your starting position.
Squat down as far as you can; the deeper the better. Keep your back straight and butt sticking out with your head up looking into the horizon. Then, push up hard until you get back to the starting position. On the way up focus on pushing with your legs and keeping your back straight.
Finally, repeat the entire movement for the desired or prescribed number of repetitions.
DO
DON'T
Perform this exercise in a smooth and fluid motion
Keep your back straight at all times
Hold the barbell tightly in place on your back
Don't go down too low because if you do, you will not be able to push back up
SPECIAL NOTES & LEVEL of DIFFICULTY VARIATIONS
To increase the level of difficulty, slow down the movement or increase the weight.
This exercise is not for beginners. Going deep really means going as far down is you can. Beginners might have difficulties pushing back up again.
Some people think it's important to load the barbell really heavy on this movement but it's really not necessary. This exercise is really about the deep dip down and the energetic push up once at the bottom. You don't need to load the bar too heavy - in fact doing so may prevent you from being able to push back up. Thus, find the optimal weight that doesn't make it too easy to squat, but also doesn't nail you to the ground when you go down.
Focus on the movement and getting as much "depth" as possible.