Teaching the squat can be a very easy or difficult task these days. Many of our athletes still do not have a strong foundation in some of the core barbell exercises: Squat, Deadlift, and Bench Press. High school strength coaches are often the gym teachers or sports coaches with little to no education in biomechanics or true strength and conditioning. However, there are still personal trainers or those with their CSCS that are unfamiliar with proper squatting techniques and an understanding of where to start when observing faulty squatting mechanics.
One of the most common substitutions we see in the squat is the "butt wink", aka posterior pelvic tilt. So what is the butt wink and why is important to understand? The butt wink is something observed at the bottom of a person's squat when they are trying to get deeper and do no have the range of motion. Subsequently, the lower back begins to round to allow the squatter to get deeper. Obviously with a load on the back during a back squat this can potentially become problematic. So what are the reasons for this substitution and what can be do about it?
In this article, Bret Contreras goes over the anatomy of the butt wink and some of the reasons it occurs.