Unusual Martial Arts training?

I once saw on a tv show wherein mixed martial arts athletes (and another similar show with more mixed athletes) travel the world to participate in the most brutal, traditional or otherwise unique training they could find. One was where they trained with an Amazonian tribe for a boat race, another was when one went high into a Japanese mountain and did things like punch trees, thrust his hands into bunches of bamboo, and walk up steps on his fists. Could someone please give me more information on techniques similar to the latter? Thanks.