I tried four sets of twelve pushups this time, and today feel only moderate stiffness. Will try five next time. Or maybe--I was feeling good about myself until I was in the weight room and saw this guy waiting for his turn at a piece of equipment. He did a bunch of perfect, straight-arm, military pushups that looked effortless. I still feel sad for my form today. I could try to work more on form. Even though my form is not in the least the same shape as that guy's!
I added one more set of those ab-killing leg lifts.
My thighs remain mighty, however.