I have what appears to be slight posture problems, and because of that, i have a really stiff left hip (and generally tight muscles). I know i should be stretching, but i've also found that when i squat, and even leg press, i tend to shift onto my right foot. I really like squatting and such, and i'd like to keep these exercises, but how can i fix posture, aside from stretching, to get the most benefit?