The average person expends way too much energy trying to jump rope. Their jumps look like donkey kicks and they jump when the rope is in the air, forcing them to jump higher to clear the rope as it hits the ground. If you jump right when the rope hits the ground, it takes a lot less effort. These are single-unders. I can do these.
Double-unders require the rope to make two full rotations (hence double-under) for each jump. Woah. Mind blowing. The premise isn't difficult but the execution might as well be brain surgery.
I have watched at least an hour's worth of video on the double-under. These are three of my favorites. I am a huge fan of the second one.
So I haven't been able to do a double-under yet but I did track down my old jump rope and get some practice in on my single-unders. Because my mother is a saint, she came outside in the disgusting humid weather on her own volition to videotape me jumping about.
And yes, that is my sorority softball uniform.