Originally posted by LineSkiCat:
One problem I have seen with squats is people often tend to focus too much on their quads (a somewhat aesthetic "showy" muscle) and neglect their hamstrings (probably the last muscle anyone looks at). A muscle imbalance will occur if you strongly favor one over the other. And with your legs, being the foundation of all lifting, you don't want this at all. Joint and structural issues can occur, along with affecting many other lifts. You wouldn't want ripped biceps with zero triceps muscle, right? Same things applies as the hamstring is used as a "curl" and quads as an "extension"
If you are going to squats on a regular basis, you should be hitting your hammys in equal fashion. Stiff-legged dead-lifts are my favorite. If your form is right (bringing the weight straight down to your shoelaces) you really feel the stretch in the hamstring. Then, barbell lunges are a great transitional move before moving onto your hamstrings, as the lunge hits BOTH the quad and hammy fairly equally.