Hi there

just want to tell you you are right... the martial arts, as well as any other east-culture things (hypnosis, meditation, imagery...etc) are extremely dangerous. I heard several times "well, I can do it, I have it under my control" and then I could see very subtle losing of trust. Not faith, but personal relationship with God became unumportant. SATAN DOES THESE THINGS STEP BY TEP... we must avoid everything that keeps us from His presence.
Once I was in these things, now I am saved, by the mercy of Jesus. And since that moment I just cannot do the both things - e.g. do yoga and worship Lord. And its worth consideration.
Bless you. May you keep your faith until the very end. :)
Dominika