The front kick may be the easiest kick to execute in the martial arts. And for that reason it is typically given the least amount of instruction. This is problematic because the kick is extremely versatile when utilized in different methods.
When executing the kick, many different applications and uses exist but no matter what the final use may be one underlying truth remains; to hit the opponent and do it quickly. The strike can be a quick distracting blow or a more committed strike that uses the body’s entire mass to push through a target.
I am going to present a couple of different ways to begin to execute the front kick and explain why and how the different applications are used.
If we began by approaching the kick from a more structured fixed front stance such as used in Karate, the kick is capable of generating lots of power but has limited ability to deviate from kicking straight forward. The way to start the kick is usually begun by leaving the front ball of the foot planted and rotating the heel in. This aligns the kick directly down the center line of the body and lets you kick directly in front of you.
A limitation of working the kick from a fixed front stance is you lose the ability to aim the kick off the center line. This limitation is an acceptable situation when you want to work from a fixed frontal stance. The reason is that you are in the structured front stance because of the stance benefits. Those benefits outweigh the limitation imposed on the kick.
The other approach is to be in a more relaxed working stance where you are not worried about squaring your chest to the target. This would be more typical of Tae Kwon Do.
When setting up the kick keep the front heel fixed and rotate the ball of the foot out. This changes the pivot point and will cause the hips to begin to twist in the same direction the foot rotated. Now as you bring the kick up from the floor your stance is not as fixed and is semi-floating, this allows you to deliver the kick along an arc in front of you. It is possible to kick a target back behind your lead shoulder.
This type of setup has its strengths and weaknesses as well. On the strong side is the ability to kick off the center line. On the down side is that because your stance is not fixed you are in essence floating on the floor and more susceptible to being knocked off your stance or being thrown.
Neither method of entering the kick is better than the other; they just have different strengths and weaknesses.
If you want to see for yourself how the two different foot rotations affect your center rotation try this:
Sit on a chair or stool that swivels. You must be relaxed when you do this drill.
Now with both feet placed flat on the floor using one foot only slowly rotate your heel in and leave the ball of the foot on the floor as the pivot point. You will notice that your chair/stool does not rotate.
Now do the same action but keep your heel fixed as the pivot point and slowly rotate the ball of the foot out. Your chair should start to rotate with the foot.
This simple change in how you setup the kick can have a very big impact on how your hip structure is presented and the ultimate contact point of your intended target.