Stretching

Stretching is about resetting the tension in a muscle that the brain will allow. Without a mechanism to limit tension, it would be impossible to walk. Your legs would separate like a giraffe drinking water. The permanent lengthening of the muscle. It is definitely not short term and is not lost if discontinued. It will last. The stretching is the method to achieve flexibility to the desired maximum for the particular requirement. It would seem pointless to achieve a greater range of motion than is necessary but the greater the flexibility over requirement then the greater the flexibility reserve.
   This translates to safety.
   There is a diminishing likelihood of injury if the flexibility is well past that which is required for your purpose. It is much like a car built with a high-speed potential. You do not need to drive the car at top speed just because it is possible. But if necessary the reserve performance is available.
   If you have no intention of asserting yourself and applying what is needed then I recommend you do not bother to attempt stretching to achieve this greater potential. You will be wasting your time and energy. You will not get the desired results and possibly only injuries. Read on and perhaps you will be inspired.
   If you know what is needed and understand what is necessary, you will want to get down to it and get some pain.

It's your reward for effort

   Stretching for its sake only is not realistic. It is useful to a degree but what it takes to achieve this greater range of motion is probably not worth the effort. Taekwon-Do without an increased range of motion in all directions (including those not yet imaginable) is dangerous. The technique will always be poor. So, separately stretching or Taekwon-Do is useful. Together the combined benefit is tremendous. This is symbiosis in action - the sum is far greater than the individual components.
   The most important aspect of stretching is to realise that discomfort is to be expected. Not only should it be expected, but it should be regarded as your reward for good quality training. It should be embraced. Welcomed.
   The attitude should be to look forward to it. If there is no feedback from the body in the guise of pain then there has not been sufficient effort expended to cause adaptation of the body to the stress.
   Stretching pains arrive about 36-48 hours after the training session and last about two days. It will then be gone (until the next time - DA). It is a different sort of pain to the usual stiffness caused by untrained muscle use. This is residual lactic acid generated through anaerobic exercise and inadequate blood flow to remove the byproducts of such energy production.
   The whole point of receiving pain is that it shows that the stretched muscles have become stretched and/or strengthened, depending on the type of work done, and are really undergoing change. More ability to accommodate the stresses of a further stretch or strength improvement will happen. The next time you train and use stretching exercises you will need to increase your range to attract more pain. This is the progressive nature of stretching. If the stretch range is not increased then the pain will not happen, but there will be no further range increases. Clearly, pain does equate to improvement.
   No pain, no gain. It really is true.
   Passive stretching is satisfactory if there is plenty of time - years! This is not always a suitable time to wait, but it is the easy way. If you keep it up. So, look forward to pain, but make sure it is caused by good technique. The pain must not be caused by injury due to sloppy or incorrect technique. The type of pain will be recognised through experience.
   A second very important factor to understand is that stretching a muscle weakens it. It is not necessary to know about muscle physiology to accept this other than the overlap of the two contractile proteins within the muscle is reduced. It is not important that children do strength work to counter this since the normal development of a child will naturally lead to increased strength in muscle. As young people continue to grow and become involved in all kinds of sport then again strength improvements will occur naturally. The person at risk by stretching without strengthening is the one who is fully grown with an associated full muscle development for their lifestyle. The stretch of this muscle will require some sort of strength improvement to make training safe. Muscle protects joints. If the muscle is weakened then the joint becomes exposed to injury - it can become unstable.
   The stretch actually resets what the brain allows. If tension failed to keep limbs (legs) together, walking would be impossible.
   Sit on the floor and keep your right leg directly in front of you. Move the left leg quite easily to 90deg left. Now change the direction of your legs - left ahead and right up towards your right. Again, quite easy. The left and right legs are not connected by either muscle or tendon so why is it difficult/impossible to take the left leg to left and right leg to right to perform a split?
   The brain must relearn the allowable tension.
   This is the real purpose of stretching.