You should also check out the book Soccer Against the Enemy: How the World's Most Popular Sport Starts and Fuels Revolutions and Keeps Dictators in Power by Simon Kuper
Aggressive behavior and sports obviously have a correlation when they are both experienced at the same time. Especially in heavy contact sports such as football or soccer. We are natural animals to begin with and when our flight or fight response system kicks in there is no other choice but to be aggressive. If we even lack this simple key to survival then we would not have survived this long as a human race. Check out this research article from sagepub publishers. Click on "full text" and it would lead you to an article about aggressive behavior and its linkage to sports. It's a research paper.