Old Ladies need Skateboards. At least is seems that way to me. Ever see a little old lady hanging on for her life, being pulled by the big German Shepard she adopted? She usually looks tired and miserable. I have a solution.
One solution is to get a skateboard. If you're going to be pulled, why not enjoy the ride? My other solution is far less fun, but a bit more sensible. Teach the dog (lets call her Molly) to Heel.
Heel means walk beside me. Not ahead, not behind, and not sniffing the trees 4 feet to the left. It is walking beside the handler (you) with Molly's head even with your legs. Lets talk about teaching Heel.
First, can the handler manage this? A person needs a decent amount of physical strength to teach Heel to a large dog. Certain collars like the prong collar can be used to lessen the importance of strength. If the handler is not capable of controlling the dog, they either need a different dog, or people to help them out.
Teach Heel by letting the dog run to the end of the leash be greeted by a sharp snap and release. Encourage Molly to come back to you. When she arrives back at your side, put her in a sit and make a big fuss over her. Praise is what is needed most. Then start walking again and do the same thing. Repeat until she gets it. As she gets accustomed to the distance of the leash and correction, shorten up on the leash. Keep doing this until she's at your side.
I call it creating the safe zone. Molly always gets a correction away from you, and always gets real praise when returning. Whenever Molly comes to you, tell her "Good Girl", and really love her. Praise Molly often in the beginning. Without the praise, she'll be scared won't know what to do. Creating a safe zone is the baseline of obedience training. If Molly is not sure what to do, she'll come to you.
When considering a dog for Mom (or yourself), please consider her strength and stature before deciding on a breed. If mom insists on a big dog to 'protect her', please be ready to help her train, or call a professional trainer. Trainers cost far less then a skateboard, helmet, or those pesky E.R. bills.