DON'T STRETCH AFTER DOING SPORT
1 - Because it doesn't prevent stiffness
Contrary to widespread preconceived ideas, stretching does not prevent stiffness in the days after intense physical effort. So there you go. When you are stiff, the muscle fibre is torn, quite literally. There is no miracle solution for repairing them: only time, heat and massages. It seems logical when you write it down, but stretching a torn muscle will not magically repair it.
2 - Because you may injure yourself
Let me be clear...and perhaps a bit annoying, but it's for your own good: few people know how to stretch properly. And if you stretch infrequently and incorrectly, you may even cause yourself injury. It's important to understand that stretching anaesthetises the muscle: so you risk going beyond your pain threshold and injuring yourself.
3 - Because it slows the blood flow
Another preconceived idea that requires correction: stretching does not eliminate waste from your blood vessels. Quite the contrary! When you stretch, your blood vessels are compressed, so logically, this prevents your muscles from regenerating after physical effort. So, by stretching, you do yourself more harm than good.