When I got my ‘big dog’ 5 years ago he was 80 lbs to my 95 and not leash trained to speak of. Then he developed leash aggression issues, so when he saw other dogs he went nuts, lunging, barking and pulling. It was difficult, to say the least. I’m very thankful the only violent incident we ever had (other dog got a nasty gash after he pinned my dog on his back on the sidewalk) was entirely the fault of the other owner.
It took a couple years, but through a combination of my own emotional progress as well as some firm discipline and plenty of liver treats, he is pretty much 100% on the leash (and in other areas) now. He responds well to commands and is very in tune with what I am asking of him and what I am feeling, even when he’s fearful (he’s still not happy about other dogs approaching him while on his leash, but its totally manageable now). It’s great to see him look to me for confidence, and come to me for help and reassurance if he needs it. We’ve grown together a lot, cheesy as it sounds.
Most important was making it abundantly clear to him I was in confident and in charge of the situation inside and outside the home; not by ‘dominating’ him, but by keeping my emotions in check, trying to project ‘calm-assertive’ energy to him, redirecting his bad or fearful behaviors, and not babying him. It only took a few short months of this before his behavior really began to change, and of course the better he got the more confident and secure I was taking him out (walks before were often downright terrifying for both of us), which was reflected in his behavior even further.
Secondly I taught him how to heel, and other commands (sit/down/stay/and the ‘nose touch’ game) using plenty of treats and praise. Every walk we would take, I would constantly be calling him back to me to go through command. This stopped him from pulling me along the whole walk, tuned into every aspect of his environment except for me. I don’t usually put him through his paces on walks any more, but he is still always keeping an eye on me as well as smelling and frolicking, because we established this habit.
At his worst (and on the ice/snow for a long time - our most memorable incident is when he yanked me off the sidewalk onto an icy street, and when I slipped and fell on my back he went into a full run and pulled me, skating on my nylon coat, down the ice for over a block) I walked him with an EasyWalk harness - it has a strap accross the chest/front legs that physically prevents most dogs from pulling. A bit difficult to use sometimes though, always needs tightening up etc. I have used the Halti and equivalents on several other dogs and I much prefer the EasyWalk.