Originally Posted by
Adam Franklin
Watch the path of the bar during any your squats. The bar is well forward of midfoot in the bottom of your squat, causing you to be out of balance (hence, your heals raising a touch).
Imagine a vertical column directly over mid foot. The bar should ride inside that column the during the entire movement. (Search "master cue")
If you have a hard time visualizing/implementing that cue, look up TUBOW.
In short, get your knees out and forward to a block of wood aligned with your toes during the first 1/3-1/2 of your descent. Then sit the hips back and down. It can be useful to think of the squat as 2 distinct movements:
1. breaking at the hips AND knees
2. only hips.
Try making your warmups two distinct movements with the TUBOW. Once your understand the movements, blend the 2 into one smooth motion.