Stretching that is characterized by a "bouncing" action is called
Ballistic stretching.
It helps efficiently to increase your range of motion but is known to create an injury. That's why they tell you NOT to do this specific exercise, unless you have a professional trainer with you that can help you.
Anyways, Good Luck! :)
The answer to your question is: B) enlarged breasts.
<em>(I hope this helps)</em>
I think it's true but I'm not to sure
