The Muay Thai ax kick is a downward striking technique where you lift your leg high and drive the heel down onto your opponent's head, collarbone, or shoulder. It's one of the more unorthodox weapons in Muay Thai -- borrowed from Taekwondo, refined for the Thai boxing ring.
What makes the ax kick dangerous is the angle. Most strikes come from the side or straight ahead. The ax kick comes from ABOVE, dropping down over the top of your opponent's guard where their hands can't reach it.
In the video above, Scott Sullivan breaks down a critical detail most people skip -- what happens AFTER your kick lands. When you're inside kneing range and you throw a knee, your opponent is going to fire a return knee right back. It becomes a contest of who gives up first.
Here's the solution: throw your switch knee, then as you come down, step across your opponent's body. Put your foot out, step down, and block off their return knee. Now you're back in fighting position with your power knee loaded and ready.
The switch is the key. It lets you block off the return and still land in position to fire again. Without the switch, you come down flat-footed and eat whatever they throw back.
The ax kick requires serious flexibility in your hamstrings and hips. If you can't comfortably raise your leg above your own head, you're not ready for this technique yet. Work your flexibility first, then build the kick into your game.
For more kicking techniques including roundhouses, teeps, and spinning kicks, check out our complete guide to martial arts kicks. Get the full system in The Ultimate Muay Thai Training System.