My Staffords pull on command,they love the weight pull and get very excited at training time,as they know they are going to be worked. Also weight pull dogs don't have to be a nightmare for pulling on the lead. It is all down to training,the dog should be trained to pull on command so therefore should not pull when onlead. Some people let their dogs pull onlead as they feel it would go against their training if they teach them not to pull on lead. Me I personally don't think it make's a difference if you train the not not to pull while on it's lead.