This technique can be hard to learn in detail online. Here are some tips for how to attempt this move, but be sure to consult someone with expertise before trying it yourself!

First, you need to get into position:

• Step your left leg forward and position it so that your shin is perpendicular to the ground and your shin is facing your opponent’s midsection. Your right leg should be behind you, bent at 90 degrees, so that its knee is roughly level with the ground, similar to a lunge position.
• Swing your left arm back so that it’s parallel to the ground and its elbow points toward your opponent’s face.

Then throw the flying knee:

• Swing your left arm forward as you pivot on your right foot and straighten both legs as you’re swinging them up towards your opponent’s face. Your kneed will come up first. This entire motion should happen very quickly—in less than a second.
• The immediate next step is to bring both feet back down and raise them off the ground slightly while returning them back into their starting position.

This is a difficult move to master and requires many hours of training both in the gym and at home. You can train this move solo but it does help if you have a partner or trainer whose holding striking pads as you may benefit from making impact to a target. Also with someone else observing you they can point out what your doing well and where you need improvement but if you do not have a partner you can always use your phone to record your sessions.