Here is a video of the standard stretches employed in my TKD classes, these are what I take my Students through before starting the dynamic art of Rhee taekwondo, they are a very important part of any training be it martial arts or other physical endeavors, some are specific to martial arts while others are generally used throughout the plethora of sports and activities undertaken by humans, by doing a regime of stretching exercises the human body operates with far greater efficiency, receives less injury, enhances your ability to do more and brightens your outlook on life in general.
The first set of stretches are known as "static" stretching and are usually held for 15 seconds each, you will notice in the video that after each part of the stretch I return back to the center point before moving onto the opposite side, these are essential to warm up the muscles in a gentle way before moving onto "balistic" stretches which take the muscles to their limit of stretch, as seen in the video, the "front leg raising" is done prior to the "front snap kick" with the "side leg raising" done prior to the "stepping through side thrusting kick".
As you can imagine, a lot of power and speed is developed in all our kicks, more so than any other martial art, so it is essential that a proper "warm up" routine is carried out before putting the body through these techniques. By tensing the muscles at maximum extension of the kick, no damage is incurred by the practitioner. However, if the muscles are tensed while stretching, no further stretch can be attained at that point.