Music playing at all times would also help. These are just a few quick thoughts. I hope this helps. My thanks in advance should you choose to answer this question. I've never heard of this variant of the bench before.
Bench lockouts are a popular assistance exercise that are used by many lifters.
Essentially you just lower the a weight a few inches from lockout and press back up again. The purpose is to over load this part of the bench so your lockout is easier. Your joints and tendons will not be used to this heavy of a weight. 1 to 2 sets of this once a week is fine. Work your abs and flexibility.