Answer:
They are fun!
Step-by-step explanation:
It can cause many injuries, but many of the worse ones can happen to the head. These injuries can cause concussions and other serious injuries. However, Other injuries can happen but they tend to do less damage such as torn joints and broken bones.
HOWEVER, these kinds of risk are extremely rare and don't tend to happen in todays age. With such good treatment options for injuries we have very little to worry about.
If you enjoy playing contact sports, play them. It is very rare to suffer serious permanent injuries.