@gemy whenever i walk him, its about 25-30 min per session. and usually we do it 2-3x a day 
 
 
and as for the sickle hock thing you pointed out.. do you think if i ask the vet about it, she'd know and see how he is?  i mean.. she didn't even point out that his back was curved so i'm not sure if she'd know. lol..  thank you for explaining what it is, but i'm still not really getting it.. watched the vid like 5x now, focusing on his leg, but still not sure.. x_x; 
on 
here, it says the one in the right is sickle hock, but when i'm looking at kupo, his leg doesn't look like that.. should i try to take another vid later and see?  (i'm probably in denial.. lol)