I met a woman yesterday with an 18 month old newfoundland, she was using a head collar and I was really pleased how obediant the dog was for her, she kept stopping to let people past in the street (and the dog would sit straight away) as although the newf was friendly she said lots of people cross the road to avoid it!

Such a shame when people do that, especially to such a lovely dog and capable owner

We have a lovely man (rather short, must be 50ish) who has two newfies, both behave lovely and he walks them both on normal collar and lead but has them off lead at the parks and woods and what not. Very friendly with everyone and superb recall. Can not fault him at all, lovely well cared for dogs.
They seem really chilled out and well mannered other than one of them will really pester for treats if you give them to him so the man watches carefully that no one feeds him, which really makes me think he is a really responsible owner.
I do realise that he would have no chance at all holding either of them back individually, never mind both together and I have never seen him with just one of them...

Barring situations like me being on a patch of ice or mud, or having caught myself slightly off-balance (I've got a horrible sense of balance at the best of times)... yep no problem.

I'm not very big and walk plenty of dogs that are physically stronger than me.

I had one client that laughed when she first met me and then introduced me to her large, exuberant, young male GSD. How I managed to keep my balance when he first tried to drag me out their front door I'll never know but I managed whilst still holding the lead. We reached an understanding on the first walk and he became a pleasure to take out in a fairly short space of time (but bucketfuls of sweat).

I think training, the right equipment and technique all play a bigger part than physical strength as well as keeping your wits about you and anticipating triggers where training may fail.

Even if a dog is physically unable to overpower you, people trip, slip etc so an emergency stop is important.

Yes i can hold him when he's lunging at the end of the lead although he can sometimes pull me a couple of steps forward. The only time he actually pulled me over was when he saw a cat while i was bent over picking up after him. He has managed to trip me up a few times though.

I can right now, when she's fully grown I'm not sure (current weight 36kgs, full grown weight maybe up to 60kgs). I try to wear big heavy boots with good grip so I can steady myself if and when she does pull, but then I also have a harness on her which is front clipping so takes less pressure to control her. I don't think just because you could not physically overwhelm a dog or control it you shouldn't own it. So long as your training is up to scratch problems should rarely occur.

I could not hold Toffee on a flat collar when he was frightened
by fireworks ( I have weak shoulders) so I now use a balancing harness which works fine so yes i think I should own this dog.

I haven't had problems holding them back but I mostly attribute that to them being well behaved. However, when I have needed to, I dig my heels in and hang on!!!

I can hold Tess and Bruce back and they are the two strongest of ours. Thankfully Im quite strong and fit, I held my horse when he reared up having dental work done, there was no way I could let him go as he had the metal piece in his mouth holding it open, and he was alot stronger than my dogs.

My mother has a rule that I generally agree with: never get a dog you can't pick up with your foot. Obviously you train and you do your best, but if the situation should eventuate that you need to get your dog away because it's being aggressive, it's just infinitely easier if it's small enough to kick away (Note: not saying kicking is acceptable in any but the most dire situations).