Thought I would give an A.T. perspective on Vern's post for today:
Vern states he would not use the Bulgarian squat for football, soccer, or hockey. He is correct, groin strains & athletic hernia are prevelent in these sports, and alludes to this squat contributing to it.
While it might be appropriate as a lead up to a SLS (single leg squat), it's important to move on. The problem begins when you load the movement. The trail leg is used to stabilize, creating isometric contractions about the hips & pelvis that are not conducive to rythmic, flowing movement. Of course you can argue that isometric contraction happens naturally in a traditional SLS, and you would be correct. But, in the Bulgarian Squat, that stabilization is initiated top down since it is traveling through the pelvis first- "neural confusion" if you will.