I'm going to switch over to the armstrong pullup plan so I can get my pullups up for the PFT and CFA. Right now I only do pullups on back days at the gym...3 sets of max. So I'm only doing pullups once a week now. The armstrong plan prescribes 5 days a week, and I'd like to be able to do the pullups on my own time. I was looking into pullup bars, the kind that go on the door. I suggested the idea to my dad but he thinks that that the door frame will break. Does anyone have any experience with these type of bars?