Stretching: how to be done?

Last week during the marathon I looked in surprise at a man leaning into a lamp post almost horizontaly stretching his calfmuscle. Hand at about a meter height and heel from the ground. This urges me to write once more about stretching. This time stretching in general.
Is stretching usefull?
exploring the web you'll find that there is some debate on the usefulness of stretching. Almost every runners does it in the belief that it helps to lengthen the muscles en increases its resistance to injuries. It also decreases muscle pain after excersises when stretching is applied during the cooling down.
The purpose of stretching
By stretching the muscle you lengthen it and put tension on the fibers. After the stretching the muscle relaxes and is in a more relaxed mode than before.
During the cooling down stretching keeps the bloodflow going, helping to get rid off the waste products in the muscle (hence the reduction of musclepain afterwards). I also thinks that the relaxation of the muscle has a good healthy effect on the tendon reducing the risk of injuries but i could not find proof of tihs quickly.
Static versus dynamic
there are different ways of stretching:

• Static
• Dynamic
• Ballistic
• PNF

Best knwon are static and dynamic. The second was out of fashion after the appearance of the book 'The Stretching Methode' by Bob Anderson.

Sequence of stretching
I never gave much thought to the sequeance in which I did my stretching untill recently someone pointed out that stretching the muscles in the upper leg first stimulates the blood flow so that when stretching the muscles in the lower leg the waste products from these muscles are better transported. Makes sence, doesn´t it?

When to stretch?
Most runners do a warming up first and then stretch before starting with some serious excercises. Taking into account the point made above you realize you should not stretch to fanatical before starting you excersises otherwise your muscles will be completely relaxed.

Other good moments for stretching are, under the assumption that it is healthy, after your excercise, during your cooling down or when you have muscle cramps.

Now let us return to the runner and his lamppost. Taking everything into account you realize stretching has no use when you put strain/force on the muscle because it won't relaxe. I don't know about you but I cannot lean into a lamppost and lift my heal from the floor without straining my calf muscle. So his pose was not effective and he still had to do another 15k.

In spite of all the fact that the debate about the use of stretching has not settled I myself find it useful. I think that on 50% of the runs I do, I do stretch it after some warming up and on 90% of the runs I stretch afterwards. (I skip when I am in a hurry).
Before I was not albe to reach my toes as the lady does in the picture...now I can. So to me it helps. And in the book on running from Haile G. he spends a few pages on stretching and it helped him to run the worldrecord so who am I to argue with him.