And they say girls have trouble with physics?

Martial Arts give you an advantage against someone with little experience n fighting. A good trick, such as the lady in this example used, can give you an advantage. Suprise can give you an advantage. But in general it is strength and size/weight that rules the day in a fight.

Just a practiced dance, nothing real. In high school we did stuff like that at wrestling practice when the coach left the mat room for awhile.