A key component of exercise is proper form in each movement you add to your workout. This applies to everything from a stationary bike to an overhead press. Before you add reps, weight, or change it up, you’ve got to make sure your form is good enough to stand any additional tests you add to it.

If you’ve never heard of butt wink, it might sound strange, but it is a common phenomenon for experienced lifters.

The risks involved in continuing to squat with butt wink under heavy loads include back injury and loss of power during the squat. Butt wink should be addressed to prevent an injury from occurring and so that you can improve your squat mechanics, increasing your ability to lift more weight safely and progress toward your goals.

What is Butt Wink?

Butt wink refers to the rounding of the lower back during the descent of the squat. In anatomical terms, it is spinal flexion and occurs due to the pelvis tucking under near the bottom of a squat. When the pelvis tucks in this way, it is called a posterior pelvic tilt. Your pelvis and lower back are connected, and so, if your pelvis starts to tilt posteriorly, you will see spinal flexion and rounding of the lower back.

The position where someone may experience butt wink will be different for everyone and can change, depending on your current mobility and whether you have adequately warmed up.

However, there will be a depth during squatting for some people that cannot be reached without butt wink. In this case, you will need to adjust your depth to avoid your pelvis tucking and causing butt wink.

The picture below illustrates the difference between the correct and incorrect squatting technique.

Why does the Butt Wink occur?

Tight hamstrings are one of the most common reasons you may have heard for the butt wink but unfortunately, it is not that simple due to the fact that there is no real change in length of the hamstrings during a squat.

This is because the hamstrings are biarticulate muscles, meaning they cross two joints and when there is equal hip and knee flexion occurring at the same time, there is no change in hamstring length. This is explained by a concept called Lombard’s Paradox.

The truth is, there is not one sole cause of the butt wink.

The cause of the Butt Wink is not limited to just mobility and stability issues but also structural issues such as the depth of the hip socket.

The two main reason the butt wink occurs is because of a stability issue or a mobility issue. If you have a structural issue, this is something that cannot be changed and will not be altered by any amount of mobility or stability drills.

1. Mobility Issue

To assess if the butt wink occurs from a mobility restriction, start in a quadruped position on the floor. Rock back toward the heels and perform a horizontal squat (see in the video below).

Perform 5 reps and observe if there is a posterior tilt of the pelvis.

Interpretation: If you can rock back without restriction, you have sufficient mobility to squat. This assessment resembles what happens at the ankles, knees and hips in a deep squat and is indicative of not having significant mobility restrictions.

2. Stability Issue

To assess if the butt wink occurs from a stability issue, perform a body weight squat. Either film or have someone observe 5 reps and note the point at which the butt wink occurs.

The next step is to do the same but hold a weight plate out in front. Observe if holding the weight plate either stops or improves the butt wink.

Interpretation: If the butt wink disappears or improves, it is clear that it is caused by a stability issue. The counter balance squat increases the anterior core recruitment and will give you a false sense of stability.

If the movement improves, it is a clear indication that you need to improve your ability to brace and hold Lumbo-Pelvic alignment as you lower down into the squat.

3. Deep Hip Sockets

People with deeper hip sockets will have less mobility when it comes to squat depth, as the head of the femur will hit the acetabulum (socket of the hip bone). The hip is a ball and socket joint, and as such, the ball aspect moves within the hip socket.

Deeper hip sockets prevent the ball joint from rotating farther. Shallow hip sockets allow for more movement and a deeper squat depth without hitting the barrier of the socket wall and preventing movement.

When the ball joint cannot move freely in the socket, the pelvis will start to tilt, resulting in butt wink. In this case, the simple fix is to widen your squat stance by moving your feet slightly wider than you normally would. See if this fixes your butt wink by having a friend or trainer monitor your back to see if you can maintain a neutral spine deeper into your squat.

Note that it is still vital not to squat to a depth that brings your spine out of neutral and leads to posterior pelvic tilt and spinal flexion. Review your squat form regularly to be sure you are avoiding a squat depth that causes butt wink.

Exercises to Prevent Butt Wink

One simple way to prevent butt wink is to widen your squat stance, as mentioned above. However, if the stance and hip socket depth are not the cause of your butt wink, there could be issues with mobility and control that can be addressed with specific exercises.

Ankle Mobility Exercises

Limited ankle mobility can also cause butt wink. To see if ankle mobility is an issue for you, perform the 5-inch wall test.

Place your foot 5 inches away from a wall while kneeling on the floor. The leg being tested will have the foot flat on the floor, and the leg bent at 90 degrees. The other leg supports you bent under and behind (in a tall kneeling position). Try to touch your upright knee to the wall in this position without your heel lifting off the floor. Test both sides—they may vary.

Stiffness, pinching, or blocked feelings can mean you need to work on your ankles before squatting. Try the following, and be sure to test your ankle mobility with the wall test after each drill to see if they work for you:

Banded Ankle Mobilization

Attach a loop strength band to a fixed point and loop it around your ankle, around the bony parts that protrude. It should rest on the top of your foot, not around your upper ankle.
Place your banded foot out away from the fixed point, so the band becomes taut. You can place your foot on a weight plate for a height boost if that feels better.
Drive your knee forward. You will feel a bit of a stretch in the back of your ankle and relief from the pinching or blocking sensation in the front of your ankle.
Push the knee straight forward for 5 to 10 seconds and release.
Repeat 4 to 5 times.

Goblet Ankle Stretch

Hold a 10-20lb weight plate, kettlebell, or dumbbell in front of your chest.
Get into your normal squat stance and squat all the way down to the bottom position. Hold your weight out as a counterbalance. Rest your elbows on your knees with the weight held out in front of you.
Move your hips to one side while driving the same side knee over your toes. Hold for 5 to 10 seconds and release. Switch and repeat on the other side.
Repeat on both sides 4 to 5 times.

Bench Ankle Stretch

This stretch will be felt in the muscle in your lower calf. Ankle mobility will be limited if it is inflexible.

Place one foot on a bench with the other on the floor.
Drive the knee directly over the toes.
Hold for 5 seconds and release.
Repeat 10 to 20 times.

Lumbo-Pelvic Control Exercises

If your butt wink is not solely due to your hip anatomy limiting your squat depth and your pelvis is tilting early and throughout the descent of your squat, you may have issues with control in your lumbopelvic region. The lumbopelvic region is the area of your lumbar spine (lower back) and pelvis. Here are some exercises that can help you with lumbopelvic control:

Quadruped Rock Back

The quadruped rock back will help you learn how to maintain a neutral spine while moving your hips and shoulders.

Get on your hands and knees and find a neutral spinal position by tucking and arching your low back until you find a comfortable, natural position.
Maintain this position while you hinge back, moving your bum toward the wall behind you.
Push back until you feel your low back may start to round (or pelvis tucking under).
Practice rocking back like this while maintaining a neutral spine.

Counter Balance Squat

Using a counterbalance in the form of a dumbbell, weight plate, or kettlebell, held out from the body, can make descending into a squat with a neutral spine easier.

Hold a light weight (5 to 10lb) such as a small weight plate, kettlebell, or dumbbell in front of your chest while standing with feet in your normal squat stance.
Extend your arms to where you feel comfortable, the farther out, the more you will have a counterbalance.
Lower into a squat with the weight extended while maintaining your neutral spine. Focus on going slowly, with control.

After performing these movement, try practicing your squat again without weight. Progress by using lighter weights than you used to until you are confident you are not allowing your pelvis to posteriorly tilt.


Butt wink during the squat can lead to back injury. It also reduces your power, limiting your ability to lift heavier weights. If you are experiencing butt wink, it’s vital that you address the cause and fix the issue.

If you are unsure what is causing your issue or you feel any pain, it’s critical that you seek professional help from a physiotherapist or other sports-related health care professional.




















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