Raising the knee up high before executing a kick has obvious advantages in competition as if you throw the majority of your kicks from the same position your opponent will have no idea if it's going to be a high/mid/or low kick, decreasing the chances of them covering up, meaning increasing the chances of you landing the kick and scoring a point.
When it comes to self protection however raising the knee to waist height before kicking is telegraphing what you are doing, so it makes much more sense (to me) to keep it as low as possible to disguise your intentions. This is a good example of what I mean:-
I am of the opinion therefore that raising the knee to waist height is a relatively new idea that has come about once competitions/sport was introduced, and that before that knees would have been kept low. Or do you think there is a valid reason in a self protection context of raising the knee to waist height?
This may sound condescending but it's an honestly held belief: If the kick is fast enough to be worth using in self defense then telegraphing simply does not matter. Also with the risks inherent in kicking it is the set up that should ensure the kick is unseen, especially in self defense.
I say this as someone who used to kick fast enough to be confident using them in the street but who probably can't anymore.
If you don't fold your leg at the knee, it would be more of a swing than a kick, wouldn't it? Would it carry sufficient power to do any damage, if we did not raise the knee up? I tend to agree with David more - that we should focus on increasing the kick-speed instead! ______________ The more you sweat in training, the less you bleed in battle.
In the video they were starting quite far apart with a guard position. Raising the knee from that distance would possibly take advantage of the 'blind angle' created by the guard. This blind angle also helps close in if the arms of your opponent are raised. Therefore the height of raised knee, I would suggest, is more dependent on the choice of kick. A front kick only needs to have the knee raised to the height of the target to be effective. However I believe it is more important to chamber the kicking leg in a side, stamping-type kick. In that case, keeping the kicking leg close to the body for balance would be important. Done with enough speed and directed waist height or below, I see no reason why a kick would not be a valid technique.
If you have the kick at waist height, when the foot reaches waist height it is at the end of an arc limited by the travel of the knee joint which like a pendulum at the top of it's arc the velocity will be zero, no matter how fast you get there.
The foot needs to travel in a horizontal direction and still needs to have velocity. So the knee may need to be above waist height to have any velocity when you hit the target.
A lot of people are not competition fighters and when in a non dojo situation it is often dark and if you are wearing black they can't see your knee anyway and they are just not that quick. You can also wave at them which is distraction. I also find by the time they realise you are really going to hit them it is too late. If you do a low competition kick and tap them you should just annoy them and really piss them off.
Personally I have the knee up by the shoulder to make sure it is really travelling when it lands and then they go down and don't get up. Of course what I do is crap as I have no style cause style is everything even if they do not fall down as I have been told many times.
Kicking faster should get rid of the worry about telegraphing or being predicted, I think in a more real situation then doing the most damage with lower kicks would be more a priority than worrying about lifting the knee to high whilst attempting a higher kick. I personally think the best time to kick is straight away to put them on their back foot, or if you have already hit them and they are wide open to a finishing kick. Also distractions like a jab or hand in their face should give you time to kick without them having too much time to react. I often wonder how the average TKD practicioner would cope in real situations if they try their fancy high volly of kicks, I think they would have to be quick to be effective unless one was just setting them up for the next more powerful kick.
I thought we talking of raising the knee for low kicks. I sure I am not the only one who has been about 3 inches too far away and felt their foot skimming up the chest and being about an inch short of the chin. The foot is at the end of it's arc going up and is stopped, it has to as it changes direction.
So if you are kicking horizontally this maximises your chances of hitting your target with real force as it gives depth, with a low knee height you kick is effectively stopped at the end of it's arc. It is basic physics. Segal does Aikido and it pains me to accept he is right.