I have been doing smith machine squats for a while, but after reading about into it, I have decided to switch to free weight squats. My problem is hamstring flexibility-- I am extremely tight. I can't get my legs past parallel without falling over backwards (this is unweighted) and I'm worried about what would happen with weight. I am also unable to sit cross legged because of this tightness, and I'm curious as to how I can alleviate it.