I finally decided to slap five more pounds onto my deadlift today. It was harder. Noticeably harder. But my knees and my back seemed to tolerate the load. I coughed on my sixth repetition and it totally screwed up my breathing. I almost decided to pause and reset before finishing the set but I would feel ridiculous bailing less than halfway through a set because of one little cough. So I managed and it was ok and I only feel a little silly.