What is the "Butt Wink" you ask? It occurs as the pelvis goes through a posterior pelvic tilt during a squat causing rounding or flexion in the lumbar spine (lower back). As the lumbar spine goes into flexion during a squat, it is not able to tolerate compressive forces well. Over time this can lead to low back pain, SI joint issues, and potentially disc injuries. So what causes the "Butt Wink" and what can you do to fix it?
What Causes the "Butt Wink?"
Lack of hip mobility and hamstring tightness are often sited as the main causes for the "butt wink." However, there is a third factor, ankle mobility, that is often overlooked and is a large contributor to the "butt wink." Let's look at hamstring flexibility first. If we have hamstring tightness, it can pull the pelvis into a posterior tilting position due to the attachment of the hamstrings on the pelvis. As we go into hip flexion during the squat, our hamstrings are lengthened at the proximal insertion (attachment on the pelvis); however, the hamstrings are shortened at the distal insertion (attachment at the knee) as we flex at the knees during a squat. So overall hamstring length is remaining relatively the same throughout the squat. Therefore, hamstring tightness is NOT a main factor in posterior tilting of the pelvis during a squat.
Next, let's dive into hip mobility. Yes, hip mobility is very important to achieve a full squat depth and can play a roll in the pelvis tucking underneath if you are not able to adequately flex your hip. As you go into a squat, the femur must rotate in the socket and if you get to a point where the femur can no longer rotate, the pelvis must rotate backwards to continue the descent of the squat. There are anatomical differences in the hip socket that can affect squat stance and depth, so it is important to screen out these differences.
Finally, the role of the ankle mobility in the "butt wink." Ankle plays a very important role in the depth of your squat and the ability to maintain a neutral spine. As you can see in the picture below, a slight increase in ankle mobility in the picture on the right allows the athlete to maintain a more upright trunk and a better shin to torso angle in the bottom of her squat. If your knees are unable to push forward over your toes in the bottom of the squat, it affects the position of your pelvis and low back and leads to a posterior pelvic tilt ("butt wink"), which causes the lumbar spine to lose its stable position.
Self Assessing Your Ankle Mobility.
It is important to know where your limitations are and how to assess and fix those limitations. An easy ankle mobility screening tool you can perform is the ankle lunge test. In a kneeling position, place your foot 5 inches (or fist + thumb length) from the wall (as seen in the image below). Next, lean forward as far as you can keeping your heel on the ground. Note how close your knee gets to the wall. Good mobility means your knee touches the wall and your heel stays in contact with the ground. Anything less than this indicates a limitation in ankle mobility.
Fixing Your Ankle Mobility Deficits.
So you found limitations during the self screen, now what? Try out these mobilization techniques to improve your ankle mobility. The first technique we are going to look at is foam rolling your calf. You want to work from the top of your Achilles tendon to behind your knee, focusing on any tight or sore spots. Perform 1-2 min/side. It is important to perform foam rolling first because it increases blood flow to the area and also creates a neurological response in the muscle allowing relaxation through stimulation of different receptors in the area. This will allow the following stretches to be more beneficial.
Next, perform a kneeling ankle dorsiflexion stretch, which will address both soft tissue flexibility and joint mobility. Start in a half kneeling position and then lean your chest forward over your front leg trying to push your knees as far forward over your toes as possible without lifting your heel (it is ok for the heel to lift slightly). You can perform this as a static stretch or a mobilization technique. I recommend doing both. For static stretching perform 2-3x/side holding for 20-30 sec. For the mobilization technique, stretch to your end range, pause, back off the stretch slightly, and then go back into end range. Perform this for 10-20 repetitions, 1-2x/side.
The third mobility exercise is a sustained deep squat stretch. Holding onto a weight plate or a barbell (rest the barbell on your knees), descend into as deep of a squat as possible. Then in this position, shift your weight more to one leg and try to push that knee as far over your toes as possible. Hold this for 3-5 sec and repeat 5x/ side (total duration in the deep squat should be at least 30 sec). Perform 2-3 repetitions. If you have difficulty maintaining balance in a deep squat or have significantly restricted ankle mobility, you may hold onto a support of a squat rack to help you maintain balance in the bottom of your squat and an upright torso.
You may be thinking to yourself, "these are great, but when should I do them?" Try incorporating these movements prior to any workout where you will be doing squatting (back squats, front squats, cleans, snatches, etc.). Make note of the difference you feel when performing these mobility exercises. Also, re-test the ankle mobility screen to see if you are making improvements, you should notice some improvement in 2 weeks with consistent performance of these exercises.
If you are dealing with an injury (related to squatting or not), please leave us a message with any questions. At Enhance, we design and implement rehab programs to help our athletes get back to their sport better than before. Whether you are someone who is not sure where to start or has had an unsuccessful rehab experience in the past, it is our goal to provide individualized care geared toward helping you meet your goals and getting you back to the activities you love.
Kassi Schuppe, PT, DPT, CSMT