A good thing to know when you're going skydiving. If for some reason you don't steer your parachute just right, or if the wind has a mean streak that day, you just might land hard enough to break something. So you do a plf. Turn your lower body sideways, hit with your feet, then roll to your knee, then thigh, then butt, then your back. Your feet will swing up in the air, and you can go with your momentum and swing yourself all the way around and stand up. If they don't teach you this when you go skydiving the first time, ask them to demonstrate. It could save you a lot of pain and money.