Hi Steve. When i'm squating and go below parallel my butt (lowerback) tends to tuck under and i have been stretching my hip flexors, hamstrings and glutes. The problem is when i go below parallel the tuck under make me use less weights. i can only squat 260x5 with ass to the grass squat but when i go parallel i can squat 320x5. Should i strengthen my hamstrings/glutes more to help at the bottom or work more on my stretching what is your take on it.