It is a jump-spinning kick (popular as an advanced kick in Taekwondo), where the rear foot of a fighting stance is used to hook kick the target after having twisted backward 180 degrees lifting the rear leg like a twist kick, jump and continue to spin another 180 degrees as though throwing a tornado roundhouse, and finish with the final 180 spin hook - all while in the air. Often times the kicking foot starts in the front leg position, and a lead in step is added to build up momentum, but counting the 540 rotation does not accurately begin until the rear (kicking) leg is lifted off the floor, even though the front leg is still on the ground at that point.
(see related link of Korean Tiger Taekwondo team member demonstrating a board break with the 540 kick).
Jumping Axe Kick or 540 Kick [Made Famous by Taekwondo].
there is the 540, axe kick, 360 or roundhouse, etc etc
First you join a Taekwondo dojang. Then you learn the basic kicks from your instructor, and when your instructor feels you are ready, he or she will teach the 540 kick to you. The basic description of the kick is that it is a jump-spin hook kick where you rotate 180 backward on one leg (pivoting on your front foot), and jump with an added 360 degrees while fully in the air, and perform a spinning hook kick. If you need any more explanation than that, then you are not ready to learn this kick.
The 540 kick is a very cool kick because it is so difficult to master, looks great when done right, and is helpful for breaking boards. To do the 540 kick, spin clockwise half a revolution (a 180o-turn) then smoothly transition into lifting your right knee as you jump off your left leg (continue spinning). While aiming at a target, don't kick right away by continue spinning until you're facing away from the target (by now, you've spun 360o in the air), then kick the target with the bottom of your right foot (start extending your kicking leg once your back is probably facing that target). It helps to bend your upper-body down as you're in midair and while you're swinging your kicking right leg up to help boost that kick's power. Once you land, you've probably spun 540o: 180o for the jump and 360o in the air, or 360o between the jump and the kick and 180o between the kick and the landing.
540
The greatest and most widely used technique used in Tae Kwon Do is the roundhouse kick (otherwise known as the "round kick"). Its advantage lies in its simplicity: it is easy and quick to execute and is the fastest way of scoring a point. However, the kick that is usually considered the "greatest" as far as complexity is the 540 kick (commonly known as the "tornado kick"). This is elaborate and difficult to execute.
540
36% of 540 = 36% * 540 = 0.36 * 540 = 194.4
28% of 540= 28% * 540= 0.28 * 540= 151.2
37% of 540= 37% * 540= 0.37 * 540= 199.8
12% of 540= 12% * 540= 0.12 * 540= 64.8
85% of 540= 85% * 540= 0.85 * 540= 459