Never got the thing about Jews in sports, some of the toughest boxers ever have been Jews.
Also a ton of modern day Jews tend to have roots in the former Soviet Union, which had great sports programs; they also probably picked up some of the genetics as well.
Max Bear put one of the most savagely brutal beatings I've ever seen on Primo Carnera, a huge HW champ of the world.
Oh, and he killed a guy in a fight.