Perhaps it's time to re look what happens when we stretch. You can read the full article Science of Running. A brief summary. We are bombarded with the words stretch, every thing from stretching helps to remove lactate (more on lactate in a coming post), stretching make you run faster, makes you less prone to injury's bla bla bla. Dont get me wrong stretching has a place at the right time, and then it is a question of static or dynamic. But there is research that suggests stretching reduces running economy and would likly hold true for other sports also. The main idea and research is that the bodys tendons act like a spring, each time when the foot hits the ground the spring is loaded and absorbs the energy from impact, and then a moment later the energy is released to let you jump, run or sprint further.
In a similar way the muscle could be looked at as a elastic band, a new elastic band is fairly springy and has lots of energy stored within which will spring back, as where a stretched out band won't have the same elasticity. So what this means is the athlete that stretched before he started his plyometric session or run is less economical when you apply the elastic ban principle to muscle.
Here is a short article from FaCT Canada on stretching. And here are the links to the research if you havnt already read the full article at Science of Running, Research 1 Research 2 Research 3.