I have had many sudden falls, but never really losing balance (that I can tell) and nothing (sensation or object) preventing my steps. It's just kind of a "hello ground we meet again" thing as I do a face plant, or rather palm plant as I always seem to be catching myself even before I realize I'm going down. Not lightheaded, no loss of consciousness, just ... . Luckily I haven't seriously injured myself with the sudden pwning from gravity.

I will say the few times I have felt myself going down, generally from tripping on something I have learned that it truly is best to just go with it. Don't fight gravity once it decides to put up a fight, you'll lose, even if you come out on top. So unless the fall will likely land you in fire, sharps or just ewwww, just go with it, let the body fall. It took me quite a few self hugs to get it down but I'm practically a pro at falling now

And really that's about all you can do, is try to make the conscious effort to wrap your arms around yourself and let your knees bend. Forwards, backwards or sideways, hugging yourself will be your best bet at protecting yourself in a fall. Tuck and roll, but it only works for me if I feel myself starting to fall, hoping one day I'll have it firmly locked in the subconscious for those random falls too.