First, let me start off by saying that I am a professional dog trainer. I've been involved in ALL aspects of dog training for the last 14 years. I know a thing or two about dog behavior.
I'm not picking on you larsen, but your advise could get someone seriously injured, or worse. Squating down is the WORST thing you can do when facing an aggressive dog! That can trigger a predator/prey response faster than you can yell "Oh S*it!". You need to remain upright for several reasons: First, you MUST be bigger than the dog. You can't do this on all fours. This is one of the main reasons why children are so often victims of dog attacks. I'm not going into the specifics (way too much to type), but if you squat down you WILL be perceived as a small, vulnerable, prey object. Next, you simply can not fight well if you're on the ground. That's the way dogs fight, not people. Last, that dog will close the gap faster than you ever thought possible. When he gets there, he's going to bite the first thing he reaches. You DON'T want that to be your face! If you're standing, "feed" him your arm. If you have a knife, that's the time to stab from UNDER the dog, not from the side, into his chest or throat. If you come in from the side, he will see it and may get you first.
One last piece of advice... When first confronted, calmly, but in a loud, firm voice, shout "KNOCK IT OFF! SIT! SIT! (repeat as needed). If he does sit, then "STAY!" And believe it or not, finish with "Good Boy/Girl!". If the dog is not a stray, but just an unruly pet, these will be familiar to him and his conditioned response will be to obey. You'd be amazed at how well/often that will work.
There is no one/easy answer. A dog (doesn't have to be a huge one) that is determined to cause you harm, is a VERY formidable opponent! My partner and I, with a combined weight of almost 500 pounds, recently had to deal with a very aggressive, 60 pound, mixed shepard. We were finally able to subdue him, but not until he lifted/dragged us both, tore the pants of my partner and use his back paws to redecorate my forearms! I have a thousand other stories to prove my point. Dogs are TOUGH! HTH
RR