my friend told me....
back then,there was this tackle done by Roy Keane
on some player
from sources...it was understood that if he had the chance,he would intend to end that *particular player* career
and true enough both team clashes...and he had his chance
bamm...he really ended that guy career
not sure whats the guy name....
and not sure if its true....

Look at the speed they are running at. And the entire body weight concentrated only on 1 leg.

But still, shockingly, I mean, shockingly to me means unexpected, I would say Riise's shot that broke Smith's leg.

That's shocking because the shot was so hard, it broke his leg.

.
Time to call for mythbusters. I don't think that the ball and human leg contained enough physics to break another human leg. More or so with the newer and more lighter balls to come every year.