Squatting And Posterior Tilt: A Look At Butt Wink

Steve Shaw
Written By: Steve Shaw
December 17th, 2013
Updated: June 13th, 2020
Categories: Articles Training
24.4K Reads
What causes butt wink, and is it something to be concerned about? Learn how to improve your squat form and reduce likelihood of injury by minimizing pelvic rotation.

Butt wink refers to the posterior tilting or rotation of the pelvis in the hole of a squat. As a lifters sinks to depth and beyond, the lower back will lose its tightness, the spine will straighten or round slightly outwards and the hips will move closer towards the direction of the feet.

This posterior rotation is a major area of concern for many lifters, and is a popular topic of conversation. Common questions include:

  • Is butt wink something to be concerned about?
  • What causes butt wink?
  • How can I improve my form and stop butt winking my squats?

This article will explore these questions and help you to improve your squat performance and safety.

What causes butt wink?

Butt wink is mainly a function of hamstring length. As soon as the hamstrings are stretched to their limits, the body is forced to try and handle further eccentric sinking in any way possible. In response, it is not uncommon to see:

  • Weight shifting to the toes and/or heels wanting to lift off the ground
  • The knees driving forward well over the toes
  • Lower back rounding

When your hamstrings are stretched to their limits, you will start to see the lumbar spine reverse its curve in response. Further depth forces pelvic rotation and lower back rounding because the hamstrings have nothing left to give.

Everyone has a finite ability to stretch their hamstrings, except for those with extremely long hamstrings and freaky genetics. Because of this reality, most of us are able to experience butt wink if we sank our squats ass to grass low enough.

Barbell Squat

Is butt wink something to be concerned about?

Yes. Butt wink is forcing your body to make changes deep in the hole. Most of these changes are unwanted and reduce squatting power. 

If your weight transfers even slightly forward from your heels to your toes, there is a strong chance that you will fold over some in the hole. During a quality squat rep the bar will remain directly over the center of your feet. When your weight is transferred forward, which is likely to happen when experiencing butt wink, there is a strong chance that the bar will move forward as well.

This small reduction of optimal leverages will place more strain upon your lower back. Now consider that this additional strain is being forced upon a lumbar spine and lower back that is currently changing curvature, and you have created a somewhat perilous situation.

As the rep mounts and you risk losing tightness, which is especially common for less experienced squatters, the pressure place upon the lower back and spine from "butt winking" is only compounded.

Looking at it from a more broad perspective, butt winked squats simply reduce the body's ability to generate optimal power. This can place unwanted stress upon numerous joints, including the knees and hips.

How can I reduce butt winking?

I recommend a three pronged attack to reduce butt winking.

Stretch and form roll the hamstrings. First, I think it is wise to routinely stretch and foam roll your hamstrings. A hamstring that is limber, loose and performing optimally is more likely to reach it's stretching potential during a squat. This will reduce the likelihood of butt winked squats.

Some recent literature indicates that you may need to stretch each hamstring 2 minutes per day to improve flexibility. Mobility WOD's Kelly Starrett recommends 6-7 stretches per day of 90 seconds each (per hamstring).

Forget ass to grass squats. Watch videos of your squat sets. Pinpoint when you start to experience butt winking and try to bring your squat depth up accordingly. Most butt winkers are NOT experiencing this form breakdown right at parallel. Most times they are sinking at least several inches below, if not going complete balls out ass to grass.

It's ok to bring your squat depth up some as long as you are hitting parallel.

Open your knees. Make sure your knees are opening properly and naturally in the hole. "Knees in" squatting can cause an unwanted hip impingement or tightness, and contribute to butt winking. 

Having your knees out properly reduces the likelihood of hip impingement, and along with it the chance that you will butt wink.

Deep Squats

Final Notes

There are many other factors that can contribute to sub-par squatting form. These include, but are not limited to:

  • Loose upper back
  • Weak grip on the bar
  • Toes in, or toes way out squatting
  • Excessive lordosis of the spine during the eccentric
  • Stance way to narrow

These form flaws can place extra strain upon the hips and hamstrings, reducing the likelihood of a quality hamstring stretch.

The point here is simple: work on your squat form. Read, watch videos and have experienced lifters assist you. The more you can improve your form, the less likely you are to experience butt wink.

One final note...never try to assess your squat form using a light weight. It can be difficult to maintain proper squat form without weight on your back. I recommend analyzing your squat form with at least with a weight equal to or greater than 70% of your one rep max.

It will be difficult to get a good quality hamstring stretch without some weight on your back.

Posted on: Sun, 12/22/2013 - 09:52

Hi Steve- Aside from squats which I do 3x week, the only other exercises I do which impact my legs are dumbbell lunges and deadlifts (1x week each). Any other support exercises you would reccomend to help with squatting? I strained a hammy doing sprints a few weeks ago and am worried that I'm not getting enough direct work on them.

Mark McKeagney
Posted on: Wed, 12/18/2013 - 20:42

Heres a youtube clip of my squatting in competition! Butt wink seems to be my demise!

Posted on: Wed, 12/18/2013 - 16:03

Some great info and tips for squatting. Back strains or more serious injuries are no bueno...