Line up with the bar over the middle of your feet. A big mistake a lot of people make is they'll start with their shins right up to the bar... the problem is when you're right up against the bar and you get down here, the bar is going to run into your shins/knees and slow you down a little bit. Start with the bar a little further away from your shins so it travels in a straight line up to your knees and it's not being kicked out in front of you.