Watch this impressive deadlift. You are going to notice something that will be evident in any true one rep max. attempt. The "cat back" posture that will occur is certainly not ideal and unless you are extremely experienced and strong, you should avoid this position. This is why we generally stay in a 3-5 rep range when building strength in the deadlift. It's important to remember it's not always the weight but the position that causes injury. Focus on midline stabilization while you get strong!
For those of you learning how to perform Olympic lifts, please observe the picture. We always stress foot positioning and many of you still want to start wide, in more of a landing position. Aside from the split, your feet will either be in a pulling (jumping) position or a landing (squat) position. You are going to get maximum power in the jump with your feet under your hips. Work on accuracy when shifting the feet.