I always walk my dog with a prong collar. He is good most of the time, but if he decides to do something or sees: food, a cat; a bird; another dog; or a rabbit, I want to have a fighting chance of holding him.
My Lab weighs 100 lbs (I only weigh 125), and I have always used a Gentle Leader to walk her.
Completely humane, it goes around their neck AND muzzle so that if you pull on the leash, their head turns sideways. Same way a mama dog trains/disciplines her puppies; by grabbing the muzzle an turning the head. It has NEVER failed. Dog can't walk straight if it's head is turned.
Gentle Leader