In taekwondo there are basically three kinds of stretches that you can do. You can perform one of them every day or you can combine all of them. When you combine all of them before and after a training session, you obviously stand to gain a lot more out of the stretches.
1. Dynamic Stretching
This kind of stretching is especially useful when it comes to kicking and gaining height. This kind of stretching involves lengthening of the muscles and the tendons while at the same time incorporating some movements. An example would be to swing your leg like you are doing an axe kick. Lift the leg as high as possible until you encounter a certain amount of resistance.
2. Relaxed stretching
This is probably the most popular and most known kind of stretching. This kind of stretching is best done after stretching. It simply involves stretching the target muscles until you feel you have hit tension. Release the muscle and continue with stretching. Most people time themselves when doing this kind of stretch. The best way to go about it is to just stretch until you feel that you have reached your limit, instead of timing yourself.
3. Isometric stretching
This kind of stretching is similar to relaxed stretching but there are certain differences. When you are doing the isometric stretch, you should tighten the target muscles and then release once you feel you have reached maximum tension. Your muscles will feel loose and relaxed and you can stretch some more. Repeat this procedure until you feel you cannot stretch anymore.