Like most of the Squat Rx videos, Squat Rx #4 (Bar Placement and Depth) is just too long, but this video is probably one of the most valuable to new squatters who have no idea how deep to squat, nor where in the world they should place the bar. Here is a quick summary of my thoughts on depth:
* Your squat should be done to a depth that you can do competently and confidently.
Squatting deeply is great, but if you get hurt every time you go heavy, what good is that? Jacked up lumbar and hips are NOT the goal. If you cannot squat competently or confidently to depth (and if deep squatting is what you want to do), do goblet squats, mobility work, hold onto a power rack, squat to a box, wear shoes with a heel, wear a belt, use a Manta-Ray, etc. to scaffold the learning process. If people give you a hard time about your use any of those tools to help you squat better, pardon my language but F*** them!
* Do NOT get hung up on the whole parallel vs. full debate thing.
I'm a huge fan of full squatting. I'm also a huge fan of squatting to parallel. Depending on your bar placement, body structure, and external hip rotation, there might not be a significant difference in actual "depth". An upright high-bar full squat will likely be maximizing ankle and knee flexion at the bottom of the hole, but may not be maximizing hip range of motion. A low-bar squat to slightly below parallel may actually have more hip flexion than a high bar full squat. There are very good reasons to do either one. Choose one, or choose both - it's not worth any kind of debate unless you are a competitive strength athlete, and even then it's not a bad idea to be able to do both competently.