Drop it low...but not too low- Is your squat depth contributing to low back pain?

“Butt wink”. We’ve all seen it, but it’s hard to describe and even more difficult to explain how it happens. By reading this column, you will learn what effect butt wink has on your spine, how you can correct it, and alternative strategies for full-depth squatting.”

Let’s discuss

“Butt wink” can occur at the end of a deep squat in which the pelvis moves from a neutral position to a posterior tilt, which causes your low back to round. When moving into a deeper squat, you run out of available hip flexion (bending forward at your hip) where your femur (thigh bone) can no longer move relative to your pelvis, so your pelvis moves relative to your femur2. In other words, your femur remains fixed, and your pelvis rotates around it, which causes the butt wink as depicted in Figure 1. Essentially, “butt wink” allows you to “cheat” to attain increased squat depth. The rounding of your low back associated with butt wink places significant stress on your spine, which can potentially lead to negative structural changes and back pain1.

So how do I prevent this?

- Use dynamic and static stretching to improve your hip flexion and internal rotation; addressed with Physical Therapy and stretches you can do on your own.

- A Physical Therapist can identify and address postural and musculoskeletal restrictions limiting your ability to squat safe and effectively.

- Strengthen the front of your abdomen by doing dead bugs and prone planks. This will help your pelvis “sit” in a better position.

- If you still notice that you have a butt wink, limit your squat depth to the point above which the butt wink occurs. 

Should you worry about not squatting to full depth?

Limiting squat depth may seem unusual or you might wonder if you are still achieving the best result from this exercise. The good news is, numerous squat depths are effective, it just depends on your fitness and functional goals!

Results from some key research in this area:

Fortunately, there is research to support that partial range-of-motion squats are beneficial. For example, Kubo and colleagues3 found that half and full depth squat training led to significant increases in strength and muscle growth. In a similar manner, Rhea and colleagues4 reported that training with quarter, half, and full-squat depth all led to significant improvements for strength and power (i.e., jump height and sprint speed). Interestingly, the quarter squat led to the greatest improvements. In short, both studies illustrate you can acquire strength, power, and muscle growth in the specific range-of-motion you train, which should be based on your fitness and performance goals. This means you can protect your spine, prevent back pain, and still make valuable changes in your performance!