Does butt wink increase the risk of back injury?

If you’ve ever watched a video of your squat and noticed your hips tucking under at the bottom, you’re not alone.  That movement, known as butt wink, is incredibly common, especially as people aim for deeper squatting or heavier weights. 

While it’s not always harmful, excessive butt wink can place more pressure on the lower back, reduce power through the hips and legs, and interfere with the efficient, stable movement you want when you squat. 

In this month’s blog, we look into understanding the technique tweaks you can make to reduce butt wink and keep your spine safe and your squats strong.

What is butt wink?

Butt wink refers to a posterior pelvic tilt during the bottom phase of a squat. 

Instead of maintaining a neutral spine, the pelvis tucks under and the lower back rounds. For some people, a small amount of pelvic movement at maximum depth is normal, but when the rounding is significant or happens early in the squat, the lumbar spine takes on more stress than the hips and legs can absorb. 

Australian physios note repeated lumbar flexion under load may increase strain on discs, ligaments and joints over time, particularly when squatting frequently, or with heavy weight [1].

Why does butt wink happen?

There isn’t one universal cause, but it is usually a combination of anatomy, mobility and control. Some common contributors include:

• Hip structure and mobility; everyone’s hip socket shape is slightly different. Some people naturally reach depth sooner than others, causing the pelvis to rotate earlier [2] 
• Limited ankle mobility; if the ankles can’t bend far enough, the body compensates by shifting backward, which can force the pelvis to tuck. 
• Core and glute control; if the deep stabilising muscles can’t maintain a neutral spine during descent, the pelvis may roll under to create stability
• Squatting too deep too soon; there’s a difference between ‘deep’ and ‘forced’. If your structure or mobility isn’t ready for a full-depth squat, pushing past your available range can trigger butt wink.

Does butt wink increase the risk of back injury?

It can. A neutral spine distributes load through muscles that are built to handle it. A flexed spine shifts some of that load to passive structures, like your discs, ligaments and joints. Over time, especially with heavy training, this may increase risk of lower back irritation or injury [1]. 

It also changes the mechanics of the lift movement, making it harder to generate force which could potentially limit performance. 

But here’s the important point: butt wink is fixable for many people, and manageable for those whose anatomy means a small amount will always occur.

How to stop butt wink when squatting

Here are some tips and techniques you can try to correct butt wink when squatting. 

1. Optimise your mobility
   • Improve your hip mobility by doing more rotations and deep hip flexion work 
   • Increase your ankle movement with things like calf stretches, and heel elevation movement 
   • Improving even one of these things can noticeable change your squat depth and stability 
2. Strengthen your foundations 
   • Build core stability 
   • Strengthen your glutes and hip stabilisers to support the pelvis. 
   • A stable trunk gives your pelvis less reason to tuck 
3. Adjust your squat technique 
   • Try a slightly wider stance or small outward toe angle 
   • Experiment with other types of squats like box squats or tempo squats 
   • Reduce depth to the point where your spine stays neutral, and then progressively build over time 
4. Progress gradually 
   • Once mobility and control improve, slowly reintroduce load. A physiotherapist can help you determine the safest progressions and identify movement patterns which could be contributing to butt wink. 

Book in for an assessment with our physios today. 

When to see a physiotherapist

If you’re experiencing lower back discomfort, uncertainty about form, or recurring technique issues, a physiotherapist can assess your squat mechanics, mobility and any muscular imbalance. 

At The Brisbane Spine Clinic, our physiotherapists develop tailored programs to reduce butt wink, enhance spinal control and improve overall squatting performance. 

Book an appointment to see one of our qualified team of physiotherapists and improve your squats today.

Disclaimer

All information is general and not intended as a substitute for professional advice. The Brisbane Spine Clinic can consult with you regarding your individual health needs.

References 

[1] Kališko O, et al. Posterior pelvic tilt during the squat: A biomechanical perspective and possible exercise solution. 2025. Accessed online: https://www.mdpi.com/2076-3417/15/23/12526

[2] Patterson CS, et al. The influence of hip flexion mobility and lumbar spine extensor strength on lumbar spine flexion during a squat lift. 2022. Accessed online: https://www.sciencedirect.com/science/article/abs/pii/S2468781221001855