The Butt Wink, Explained

The “butt wink,” a backward tilt of the pelvis at the bottom of a squat, causes the lower back to round and flex, potentially placing unnecessary stress on the spine and increasing the risk of injury. A study published in the Journal of Exercise Science and Fitness required participants to perform squats without a butt wink to prioritize safety. (1)

However, Marc Surdyka, a Doctor of Physical Therapy, Orthopedic Clinical Specialist, and cofounder of E3 Rehab, argues that the concern surrounding the butt wink may be overblown. 

Surdyka explained that the term “butt wink” lacks a universally accepted definition.

“If I asked one hundred different physical therapists, coaches, and gym goers, I’d likely receive various answers,” Surdyka stated. He believes a butt wink is most commonly associated with the bottom of a squat, where posterior pelvic tilt combines with lumbar spine flexion.

https://www.youtube.com/watch?v=ohsByYZ-zpY&ab_channel=E3Rehab

Butt Wink Factors

Several factors can contribute to the occurrence of a butt wink:

• Anatomy
• Range of Motion
• Squat Depth
• Skill or Technique  

Anatomy

Lifters often vary in femur length, which can impact performance. For example, taller lifters with longer femurs may find squats challenging due to having more difficulty maintaining an upright torso. (2)

Range of Motion

This connection is particularly relevant to anatomy, specifically the hips and ankles. A reduced range of motion in ankle dorsiflexion often demands a greater forward trunk lean during a squat to maintain balance and prevent falling backward.

Furthermore, excessive forward trunk lean during a squat can cause the hips to reach their maximum range of motion before achieving the desired depth of the squat. To compensate, additional movement from the pelvis and lower back may be required, often resulting in a noticeable butt wink as the body adjusts to achieve proper depth.

Squat Depth

A deep squat demands a greater range of motion, which increases the likelihood of experiencing a butt wink. A butt wink can often be attributed to an improper squat stance or a lack of body awareness.

Is a Butt Wink While Squatting Harmful?

There is no evidence to suggest that a butt wink during a squat is harmful. “There is not even research indicating that flexion of the low back during a squat puts you at a greater risk of injury,” Surdyka noted. 

The notion that lumbar flexion is inherently harmful stems from research on pig spines, where scientists repeatedly flexed and extended the spines under heavy loads until damage occurred. (3) While Surdyka doesn’t advocate for lumbar flexion or a posterior pelvic tilt during squats, these movements naturally occur in exercises like deadlifts, kettlebell swings, good mornings, and strongman lifts. (4)

“This information makes it difficult to dichotomize butt wink as either good or bad. Instead, consider when it might be worth intervening, but this is also a challenge,” Surdyka explained. 

Consider someone’s history and goals when evaluating butt wink:

• If someone consistently experiences pain during lumbar flexion, especially when showing a noticeable butt wink at the bottom of a squat, modify it.
• A coaching opportunity arises when a new lifter lacks body awareness and displays inconsistent technique with each rep.
• If the goal is to build quads, the butt wink at the bottom of the squat may not meaningfully contribute to that objective. 

A powerlifter or weightlifter who has been lifting for years without injury, even while consistently butt winking, can likely continue their current technique without concern. Forcing a change in form might hinder their performance. Conversely, some athletes squat with flawless technique yet still encounter pain or injuries, highlighting the complexity of individual biomechanics.

How to Fix a Butt Wink

According to Surdyka, limited ankle dorsiflexion can bring four key considerations to mind: (5)

1. Squat patterns naturally vary from person to person, influenced by anatomy, personal preferences, and other variables.
2. If someone is new to squatting, expect their dorsiflexion to improve with consistent practice and exposure to the movement.
3. Tools like heel lifts, weightlifting shoes, or wedges can provide support when needed.
4. Incorporating exercises to enhance the range of motion can improve flexibility and mobility. 

If the issue lies in technique, consider these three options:

1. To limit range of motion, consider box squats or another form of external feedback.
2. If squatting with a narrow stance, try adopting a slightly wider stance. (6)
3. Pause squats or tempo squats can enhance body awareness and positioning. (7)

Wrapping Up

Surdyka suggested that unless your specific goal involves barbell back squats or parallel squatting, there’s no need to include this in your routine. Instead, consider alternatives like front squats or goblet squats, which promote a more upright posture, or explore Hack squats and Smith machine squats for added variation.

Using weightlifting shoes or wedges can enhance squat technique. “One of my favorite lower body exercises is the split squat, which allows for complete control of your trunk position,” Surdyka said. 

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References

1. Kim, S., Miller, M., Tallarico, A., Helder, S., Liu, Y., & Lee, S. (2021). Relationships between physical characteristics and biomechanics of lower extremity during the squat. Journal of exercise science and fitness, 19(4), 269–277. https://doi.org/10.1016/j.jesf.2021.09.002
2. Falch, H. N., Haugen, M. E., Larsen, S., & van den Tillaar, R. (2023). Association of Strength Performance in Bench Press and Squat with Anthropometric Variables between Resistance-Trained Males and Females. Journal of functional morphology and kinesiology, 8(1), 19. https://doi.org/10.3390/jfmk8010019 
3. Callaghan, J. P., & McGill, S. M. (2001). Intervertebral disc herniation: studies on a porcine model exposed to highly repetitive flexion/extension motion with compressive force. Clinical biomechanics (Bristol, Avon), 16(1), 28–37. https://doi.org/10.1016/s0268-0033(00)00063-2 
4. McGill, S. M., & Marshall, L. W. (2012). Kettlebell swing, snatch, and bottoms-up carry: back and hip muscle activation, motion, and low back loads. Journal of strength and conditioning research, 26(1), 16–27. https://doi.org/10.1519/JSC.0b013e31823a4063
5. Kim, S. H., Kwon, O. Y., Park, K. N., Jeon, I. C., & Weon, J. H. (2015). Lower extremity strength and the range of motion in relation to squat depth. Journal of human kinetics, 45, 59–69. https://doi.org/10.1515/hukin-2015-0007
6. Straub, R. K., & Powers, C. M. (2024). A Biomechanical Review of the Squat Exercise: Implications for Clinical Practice. International journal of sports physical therapy, 19(4), 490–501. https://doi.org/10.26603/001c.94600
7. Martínez-Cava, A., Hernández-Belmonte, A., Courel-Ibáñez, J., Conesa-Ros, E., Morán-Navarro, R., & Pallarés, J. G. (2021). Effect of Pause Versus Rebound Techniques on Neuromuscular and Functional Performance After a Prolonged Velocity-Based Training. International journal of sports physiology and performance, 16(7), 927–933. https://doi.org/10.1123/ijspp.2020-0348

Featured image via Shutterstock/Drazen Zigic