http://www.bbc.co.uk/...-environment-11153466
The scientist have explained it but they omitted one important fact, you can only get that much spin with the outside of the boot and that is very difficult, they often end of miss hitting. He hit this sweet and you can tell by the way he almost ends up facing the wrong way after hitting it that the outside of the left boot really connected well and imparted huge spin. Magnificent strike.