Question from Jonathan Zack

This question was submitted by Jonathan Zack. If anyone has an answer please add it as a comment.

Hi ...does anyone know a specific source of rabbenu or the the saba (not someones opinion) whether it is permissable to practice yoga, tai chi, etc.............. 

some say totally assur and connected to avodah zara others say if kavanot are ok i e Hashem = OK.....

PLEASE NO OPINIONS ...RABBENU , REBBE NATAN OR SABA.......

THANKS

BLESS

YOCHANAN SHMUEL YITZACK HA LEVI