Lately, on my working sets for squat, I lean forward excessively on some repetitions. This means that the weight ends up on my toes, and i'm essentially GMing the weight up, or stalling. This seems to be caused by my hips rising faster than my shoulders. Any advice on fixing this? Could it be a glute activation problems? Do my hip muscles need stretching? Am I not focused enough? Mehdi @ stronglifts has an article on this. Any additional advice or did he cover everything? Thanks. edit: I'm doing low bar squats, and working weight is 245lbs.