Thanks for the links and advice guys. I might give that a try with the pushups AND pullups.
But right now, I have a small stupid injury. I'm not sure what happened precisely, but it appears I pulled part of my thigh (top of the quadriceps just below the hip, center of the leg). Needless to say it is difficult to walk... hopefully it passes in a day or two.
It was very hot yesterday and I took a long walk. That's the only thing that I think may have caused it. It hit me as I was sitting down at my desk, which is very weird.