Butt Wink: What It Is, Why It Happens, and How to Fix It

You've probably heard someone at the gym mention "butt wink" — that posterior pelvic tilt at the bottom of a squat where your lower back rounds slightly. It's become a hot topic, with some treating it as a major injury risk and others dismissing it entirely.

The truth is somewhere in between. Let's break down what butt wink actually is, when it matters, and how to address it.

What Is Butt Wink?

Butt wink is the posterior pelvic tilt that occurs at the bottom of a squat. Your pelvis rotates backward, causing your lower back to lose its neutral arch and flex (round) slightly.

What it looks like:

• Neutral spine throughout descent
• At the bottom, tailbone "tucks under"
• Lower back goes from slight arch to flat or rounded

How much is normal: Some pelvic movement at depth is normal and unavoidable. The concern is excessive flexion under load.

Why Does Butt Wink Happen?

1. Hip Anatomy

Your hip socket (acetabulum) has a specific shape and depth. At some point, the femur (thigh bone) hits the edge of the socket. When that happens, further depth must come from somewhere — usually the pelvis rotating.

The reality: Some people can ATG squat with no wink. Others hit bone-on-bone well above parallel. This is structural and can't be "stretched" away.

2. Hamstring Tightness

Tight hamstrings pull on the pelvis as you descend. When the hamstrings reach their limit, they pull the pelvis into posterior tilt.

Test: Can you touch your toes with straight legs? If not, hamstring flexibility may be a factor.

3. Ankle Mobility

Limited ankle dorsiflexion prevents the knees from traveling forward. To compensate, you lean forward more, which can increase demands on hip flexion and contribute to butt wink.

4. Motor Control

Sometimes it's not flexibility — it's coordination. You have the mobility but not the control to maintain neutral spine at depth.

5. Stance and Technique

Too narrow, too wide, wrong toe angle — all can force you into positions that promote butt wink.

Is Butt Wink Dangerous?

The Fear

Spinal flexion under load can increase disc pressure and injury risk. A rounded lower back during heavy squats seems obviously bad.

The Reality

Mild butt wink: Probably fine. A slight loss of arch at the very bottom with moderate weights is normal and unlikely to cause problems.

Severe butt wink: More concerning. Significant rounding under heavy load repeatedly may increase injury risk over time.

The Nuance

• Most people have some butt wink and squat for years without injury
• Heavy loads + significant flexion + fatigue = higher risk
• Context matters: bodyweight vs. 500 lbs is very different
• Individual tolerance varies

Assessing Your Butt Wink

Video Assessment

1. Set up phone/camera at side view
2. Squat to full depth (bodyweight first)
3. Watch your lower back at the bottom
4. Note where pelvis starts to tuck
5. Repeat with load — does it get worse?

What You're Looking For

• Mild: Small tuck at very bottom, returns to neutral easily
• Moderate: Noticeable rounding, occurs higher than rock-bottom
• Severe: Significant rounding, occurs well above parallel, stays rounded

How to Reduce Butt Wink

1. Limit Depth (Temporarily)

If you wink at ATG, stop just above the wink point. Build strength and mobility there before going deeper.

How: Video yourself and identify exactly where wink starts. Set that as your temporary depth limit.

2. Improve Hip Mobility

If tight hips contribute to the problem:

90/90 Stretch: 2-3 sets of 30-60 seconds each side Pigeon Pose: 2 sets of 60 seconds each side Deep Squat Hold: Accumulate 2-3 minutes daily Hip Flexor Stretch: Address anterior hip tightness

3. Improve Hamstring Flexibility

If hamstrings are the limiter:

Romanian Deadlift Stretch: Light weight, hold at bottom Seated Hamstring Stretch: 2-3 sets of 30-60 seconds Jefferson Curl (light): Controlled spinal flexion for mobility

4. Improve Ankle Mobility

If ankles limit knee travel:

Wall Ankle Stretch: 3 sets of 30 seconds each Heel-Elevated Squats: Plates or squat shoes under heels Calf Foam Rolling: Before mobility work

5. Adjust Stance

Experiment with:

• Wider stance: May allow better hip clearance
• More toe-out: Opens the hips
• Narrower stance: Works better for some anatomies

Small changes can make big differences in where you hit bone-on-bone.

6. Improve Motor Control

Sometimes it's not mobility — it's control.

Tempo Squats: 3-4 second descent, focus on position Pause Squats: Hold at bottom, maintain neutral Goblet Squats: Weight in front helps maintain upright torso Box Squats: Sit back to box, reload neutral, stand

7. Brace Harder

A strong brace helps maintain spinal position.

Cue: "Big breath, belly out against belt, hold throughout" Practice: Perfect your bracing at light weights before loading heavy

When to Accept Some Butt Wink

• Bodyweight or very light loads
• Minimal wink right at rock-bottom
• Anatomy limits prevent going deeper without it
• No pain or history of back issues
• Competition depth requires it

When to Be More Strict

• Heavy loads (>80% 1RM)
• History of back pain or injury
• Wink occurs well above parallel
• Pain associated with the position
• Progressive worsening over sets

Sample Butt Wink Reduction Program

Daily Mobility (10 min)

• Deep squat hold: 2 minutes
• 90/90 stretch: 60 seconds each side
• Pigeon pose: 60 seconds each side
• Wall ankle stretch: 30 seconds each side

In Your Workout

• Goblet squat warm-up: 2x10 (focus on position)
• Pause squat working sets (stay above wink point)
• Tempo descents (3 seconds down)

Weekly

• Video check once per week
• Gradually increase depth as mobility improves
• Adjust stance as needed

The Bottom Line

Some butt wink is normal and not worth obsessing over. Severe butt wink under heavy load deserves attention.

Address the cause: hip mobility, hamstring flexibility, ankle mobility, or motor control. Limit depth temporarily if needed. Adjust stance to find your best position.

Don't chase ATG depth if your anatomy doesn't allow it. Squat to the depth you can maintain good position, and build strength there.

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Related:

• Squat Depth Guide
• Hip Mobility Exercises
• Squat Technique Guide