If you're continually missing PR attempts off the floor, try using block pulls off 3-4 inch blocks. This will allow you to challenge your hip and back position at an angle that mimics where the bar will be right after you get it off the floor.
Experienced lifters should do these with a quick set-up and a rapid descent.
related posts
Q & A with one of the world's premier strength coaches.
Not many people can do it. Too bad, it's one of the best core exercises out there. Here's how to work your way up to it in five steps.
The Ohio Hellraiser talks gaining weight, losing fat, and how to make the most out of crappy workouts.
Take a few tips from ridiculously strong powerlifters and apply these training methods.