violence in sports

2 answers

football causes concussions
boxing is an obvious one but where is your question?
Jiskha is not a search engine. If you use Google.com for a search tool, and the words <violence sports>, you will get many references on that subject.

A large fraction of the sports-viewing public wants to see violence in sports such as boxing, wrestling, so-called mixed martial arts, roller derby, hockey, auto racing, and animal fighting. It seems to be a basic human need for many people.