Butt Wink in the Squat: Is It Dangerous?

Written by: Kevin Cann

The butt wink in the squat is an often overly criticized component of the movement. This does not come without warrant. The lower back is one of the most commonly injured parts of the body when squatting, and it makes sense that any unwanted movement of the lower back would increase our risk for injury.

A butt wink is when our pelvis goes into posterior tilt and tucks underneath us at the bottom of the squat. The problem associated with the butt wink is that the spine goes into flexion and then back into extension. This movement has been associated with spinal disc injuries in the literature.

The loading of the butt wink may cause SI joint issues as well. The posterior tilt puts added stress on the ligaments of the SI joint to stabilize it and may be a mechanism of injury. Now this may sound scary to those of you that have a bit of butt wink in the bottom of the squat, but it may not be as bad as you think.

There are plenty of people in the gym that squat often and have a butt wink, and many of them never experience any type of lower back pain. What could be the difference between those that experience pain with a butt wink and those that do not?

Some might tell you that the reason for the butt wink is tight hamstrings. I do not like to use the word never, but it is almost safe to say that tight hamstrings are never the cause of butt wink in the squat. The thought is that the tight hamstrings actually pull the pelvis under. The problem with this theory is the hamstrings are a bi-articulate muscle group. This means that they cross two joints, in this case the pelvis and the knee.

When we bend the knee we actually give the hamstrings some slack. So when we descend in the squat we are giving the hamstrings slack at the knee joint and stretching it at the hips. Overall there is very little to no change in stretch of the hamstring muscle group. If this is the case, the hamstrings being tight cannot be the culprit of the butt wink.

In fact, in my ten plus years of coaching and in performing hundreds, if not thousands, of assessments, tight hamstrings are very rarely an issue. In most cases it is just teaching them how to organize their body optimally and stabilize those positions. This allows the correct muscles to stabilize the pelvis, giving the hamstrings a break, and also puts the glutes in a better position to extend the hips.

Anatomy may play a role in squat depth. The deeper the hip socket and the more vertical angle of the femoral head, the harder it will be to get to depth without some rounding of the lower back. If you are a competitive powerlifter you must squat to depth for your sport. You will have to round your lower back to get there.

This does not mean that you are destined for lower back issues. I do not think all rounding is bad. Some lower back rounding under control and with submaximal weights is not inherently dangerous. With that said it is not ideal either. How do you know if you are one of the unlucky ones with an anatomical disadvantage? I use a quadruped hip rock assessment. You setup on all fours with your knees as wide as your squat stance. From here rock straight back. If you can get the hip crease past the knees without rounding here, you can do it standing. I have found very few people that could not squat to depth properly.

So if it is not tight hamstrings, or our anatomy limiting our squat depth what could it be? Well, first what changes between the hip rock assessment and the squat? Load and stability requirements change. Often times butt wink occurs because our setup is not ideal.

If we setup with our hips in anterior pelvic tilt and our lumbar spine in extension we will round at the bottom of the squat. The body will always choose the path of least resistance for movement, and if our lumbar spine is already in a position to be mobile, it will take over end range from the hips and finish the movement.

Another reason we may see the butt wink in the squat is we do not optimally centrate our hips. We need to externally rotate our hips to pull the head of the femur back in the hip joint to give us the proper space necessary to squat to depth. If the femur starts forward in the hip socket, it will pinch tissue before we reach depth. In order to avoid this our body will just flex the lumbar spine.

Lastly, you just might not be stabilizing your spine properly. This all starts with proper breathing. Often times I will see people take their breath through their chest and neck and then attempt to regain tightness in their abs. We will need to get tight before we unrack the bar and continue to only get tighter.

We need to breathe deep into our belly and push it down and out. This helps fire all of the muscles that stabilize our low back including our obliques. Often times when I cue breathing, I will feel the sides right under the ribs to see if they are tight. Often times, they are not. Fixing this piece can help fix the butt wink.

Once we get tight with our breath we need to maintain this tightness as we squat. As we squat we need to think of making our belly bigger the entire time. This will help keep our abs tight throughout the movement.

Sometimes it is just a matter of perfecting motor control and getting stronger. Mastering squat technique takes time. Keep the weights at an intensity that allows you to master technique and make adjustments from rep to rep. This not only leads to improvement of technique, but also allows the tissue to adapt to the stress and become stronger. Leave your ego for the platform.

Is the butt wink bad in the squat? It is not ideal, but under control and submaximal weights it will probably not lead to injury. Some of us may have anatomical pieces that disallow us to squat to depth without the butt wink. With that said, we all need to work on it. We do this by bracing our abs, externally rotating our hips, and breathing properly and keeping the weights light enough to perfect technique.

Kevin Cann

Kevin is the Director of Strength and Conditioning at Total Performance Sports in Boston, MA. Kevin holds a master’s degree in Kinesiology and a bachelor’s degree in health and wellness with an emphasis in nutrition. He is a certified performance enhancement specialist through NASM. He is currently a student of former Team Russia Powerlifting Coach Boris Sheiko. He works with people of all walks of life from rehab, to weight loss, and to competitive athletes. Check out his site at www.totalperformancesports.com