In the bottom position of a squat the "Butt Wink" - also known as a posterior pelvic tilt - is one of the most common faults we come across in people. I would give a minuscule allowance to lumbar flexion (depending on the lifter and their experience) but when your pelvis starts to rotate backwards and you've got a loaded barbell on your back... You're gonna have a bad time.
Why does this happen? It could be a number of reasons ranging from the length or tightness of your hamstrings, rectus femoris, control of your erector spinae, lack of ankle dorsiflexion, hip mobility, glutes not working, no core stability, no motor control or you just simply haven't been shown how to.
I like to introduce people to have two squats (well 3 but we'll save the third for another blog) on the left you'll see what I like to call your "Performance Squat" which is the squat I would teach people to only go to the depth that they can maintain a neutral spine, upright torso, heels planted and an almost anterior pelvic tilt throughout the entire movement. The second I like people to work with on the right is your "Mobility Squat" or "Resting Squat" which is a haphazard anything goes kinda guy. This is the butt wink, notice the lumbar flexion and also drop in thoracic extension further upstream.
"The Performance Squat"
Number one, set up your camera and take a video of yourself doing an air squat from behind and from the side, look for the key components of the squat, neutral spine, weight in all of the foot not shifting forward, heels planted, knees tracking toes, chest up, ankles in line, lumbar extension.
What you feel like you're doing and what you're actually doing are two VERY different things. You can swear till you're blue in the face that you're not doing something until you are actually given video evidence. Even then you'll still assume that they "just caught a bad one" while your coach or trainer is wondering how their words have bent you into this amazing pretzel position somehow.
Your performance squat is the depth you can reach maintaining all the good points of performance and this is the squat you should use when doing any sort of weighted exercise like front squats, back squats, overhead squats or any exercise routine that requires you to do a squatting motion for continuous reps with weight.
Not everyone is ready to squat "ass to grass" does this mean you shouldn't squat? Hell no! It does mean if you have mobility or stability problems find a safe depth to squat weight without compromising your back and injuring yourself WHILE improving your range of motion. For some people (like me), that can take a stupidly annoying amount of time and be very disheartening but always remember if you're actively working on improving something it will improve a lot more than burying your head in the sand and doing extra shoulder presses.
"The Mobility/Resting Squat"
I like this guy, he's like a stoner "yeah man, whatever" if your ankles are collapsing in and your backs rounding chillax dude, there's no weight here it's just you and the floor. This squat is all about squatting, just sit there, move about, twist, turn, bounce, sway, rock and try and relax into it. The more time you can spend with a low hip angle the more it will feel like a natural resting position and in turn will start to increase the depth of your performance squat, try to hit this position multiple times a day, if you feel like you're just going to fall over every time you do sit down into it then elevate your heels slightly for a while until it feels easier. A flat footed squat is what you're after here eventually but remember NO ADDED WEIGHT!
Would you do a deadlift with a rounded back? Why would a weighted squat be any different? Sure it only happens at the very bottom for a second, would you kick up into a handstand with your elbows bent? Sure if you're the handstand push up master you might "get away" with it, but a fiver says it won't look pretty. I've seen some seriously strong dudes "get away" with a lot of shit, where they've lacked in flexibility, posture and technique they've completely dominated with brute force and pig ignorance, but I've also seen them hit roadblocks very quick and can even hurt themselves because they're SO strong that they can throw weights around that their bod, structurally, cannot handle which is VERY dangerous. Have your sight set in the bigger picture, get your technique right, address your weaknesses THEN add your strength and see what you can do.
You can search the internet and journals for years upon years for squat mobility drills and stretching routines and find some really good stuff but the major crossovers you'll come across stretching and mobility wise are: the frog, downward dog, cobra, the pigeon and the couch stretch. Also working on your ankle range of motion and thoracic extension (big one for desk workers) on top of your hips will really improve your squat. These poses in a warm up I would say do more dynamically and save static versions until post workout.
Mobility tools I'd say roll out your quads, hamstrings Iliotibial bands, adductors and calves, get a lacrosse ball into your hip flexors, extensors and glutes. Stability wise you'll see the goblet squat, wall squats and assisted squats (holding on to something) pop up a lot, I would add lunges into every warm up, front, side, back, across, diagonal and single leg squats (get squat stance and move one leg further forward, keep more weight on that leg and squat letting the back heel come up).
Stretch all you want but if you can't learn how to stabilise your trunk and activate your bum cheeks (glutes) you're not gonna get those big numbers and nice buns! SQUAT SQUAT SQUAT! Thanks for reading :)