My grandfather made note that Native American tribes never practiced hand to hand combat of any type, only armed combat. I thought that seemed unlikely, as hand to hand combat is easily the most natural to humans. So did any native tribes practice martial arts or purely hand to hand combat?
Hand to hand combat was certainly part of the cultural practices of native Northern California. The Hupa, Yurok, Karuk and Tolowa played a game simply called "stick". It was played on an open sand bar by teams of around 3 members per team. It involved two teams that carried sticks with a slight hook at the end. The goal was to carry or pitch an item made up of two wooden billets tied together with a leather thong to a preestablished goal. It is described along with pictures of the playing pieces and sticks here. Basically, it was a "no holds barred" event where wrestling and all variety of fighting was allowed. Many stories of famous stick games are still told. They are replete with descriptions of players choked with opponents sticks or having ones head driven in the sand.
Lest you have any doubts about the connection between this game and hand to hand combat, see the videos here and here. The second one is the best. Edit: added more video. Edit 2. Changed number of players after more reading.