A Charleston kick on the BOSU-ball is something that would work your hamstrings, your quads, as well as getting your heart rate up. So it's kind of a fun exercise as well. What you do is, in slow motion, you put one foot in the middle. You bring your knee up. You kick out. You bring your knee back. You come down and then you touch. So that's the slow motion version of it. The fast motion is you kicking and down, and so you kind of add a little hop to it here, which gets the cardio going, and of course you have to stabilize yourself then.