I have a rescue APBT I got about 10 months ago. He's about four and a half and i was looking to getting him started in wright pulling. Nothing competition serious, but just some to keep him in shape and physically fit. However, anytime I bring a harness near him and try to put it on him, he freaks out. He growls and snaps and shakes and everything. Now he was used as a fighter and got stabbed 7 times, so I don't know if that has to do with it or what. He adores collars like you wouldn't believe and will let you put all the collars you want on him. (I maxed out at 5, that's all the collars I own) but when a harness comes into play, he freaks out. Any help?