Quick Tip: How to actually FIX BUTT WINK (The Final Answer)

Butt wink describes the rounding of the lower back(also known as posterior pelvic tilt, if you're a nerd) in the bottom position in the squat. This is a problem since it intervenes with the stretch-reflex and increases the chance of injury when working with heavy weights. 

I should probably mention off-the-bat that slight lower back rounding is NOT a major problem that most people need to be concerned about. As Jonnie Candito outlined in this video, slight lumbar flexion in the squat is common amongst most Olympic weightlifters, who are literally built to squat and have super mobility! 

If Lu Xiaojun cannot maintain a perfectly neutral spine in the bottom position,

 I highly doubt that we can!

In saying this, butt wink can be minimized in order to maximize performance and longevity when training squats. The most basic thing you should do is ensure that your ankle and hip mobility is on point. Check to see how far your ankle can push forward past your toes. Also, warm up your hips prior to squatting by doing leg swings and hip rotations, and by warming up those adductors. Doing just a warmup set of cossack squats will allow you to open up your hip and sit forward in the squat rather than backwards,

Assuming that you have tried all the above, it is now time to talk about morphology and anatomy. Firstly, some people are not built to squat deep. Depending on your hip morphology, the level of depth that you can squat into may be greatly reduced, and this is something that largely cannot be changed. The best you can do is widen your stance and flare your toes out more. This topic is discussed in further detail by Bret Contreras in this video. Secondly, the ratio of you tibia and femur length may also limit your squat depth. If you are a tall lifter with long femurs and relatively shorter tibias, it will be much harder for you to achieve full depth with a completely neutral back. On the other hand, if you are a shorter lifter with shorter femurs, it will be easier to hit depth. 

A fix for this issue is using a heel elevation. Olympic weightlifters like using weightlifting shoes/squat shoes, but bodybuilders but small plates under their heels. Either way, this heel elevation increases the relative length of your tibia bone, and this makes hitting the bottom position much easier. 

Weightlifting shoes have a heel elevation which increases the relative length of the 

tibia bone. I recommend the Nike Romaleos 2 or the Reebok Legacy Lifter 2/3

A good way to test if you have the general mobility to achieve a sound bottom position is by performing the close grip overhead squat. This is like a regular overhead squat but with a shoulder-width grip instead of a wider snatch grip. If you can go to below parallel depth with this exercise, then you have the adequate mobility to squat irrespective of if you have butt wink on not. If you cannot perform this exercise, work up to it until you can, and then you can squat deep for the rest of your life!

Enjoy!