I have a close friend of mine who suffers from brain damage from a car accident. As a result of this damage, he's had lucid dreams/OBE's that he can't tell the difference between those and reality. He's made his own totem (long before "Inception" was even a movie) to differentiate between waking consciousness and the dream world. Anyways, he'd get lots of nightmares and he began practicing escape and self-defense techniques in his dreams.

Lo and behold, he got better and better and eventually, his self-defense training in the dream world began to manifest itself in the physical world. To this day, when we spar, I still can't believe some of the things he's been able to do.

So, yes. Any sort of training/knowledge obtained in the astral/dream/ethereal/metaphysical world can be brought back into the physical world for use. Good luck!