I don't know if my think is right but you can try to check this link:
Thank you for your answer. However, I want to find a shop in Xian. :)
Hi Vanlentin, I think you can find what you want near stadium, there are some outdoor supplies shops, but much expensive. Or you can check on Decathlon near 南二环. As I know there are some spots club also rent sports equipment:)
If you really want to buy, I have a friend who love different sports and he runs an outdoor sports club, he knows where we can buy good sport stuff, and he will guide me to buy hiking shoes, it may much cheaper:) if you want to go buy with us, contact me soon:)
Ps: Nice to see you last night at Near Wall bar.