You could do 10,15 or 30 second sparring rounds which would at least get you banging from the pocket.
Very true. Even in sparring, those first few seconds are the hardest, even with someone you've played with for years. I was thinking more about the real nervousness and
real uncertainty you get when you realize someone actually wants to hurt you, rather than spar with you.
That period of disorientation, that most key part of any real self-defense encounter, is what you really can't synthesize (ethically).
For most of us, that's something we'll only ever experience once or twice in life, if we're unlucky.
For the record, I don't really consider chest-thumping, ego-driven "bar-fight" type encounters to be truly self-defense, in many respects. In many ways, they're more like angry sparring matches; you generally know they're coming, you both sort of agree, and there's usually at least some semblance of civility and an unspoken rule-set, as opposed to real, terrifying assault, which most people never encounter, you know, the whole actually trying to kill you, rather than just wanting your wallet or showing off for your buddies...
That second, more serious case, is where you
need to fall back on reactions instilled through years of training. It's not you-lose-you-get-bruised, it's embarrassing; it's much scarier, which is why the more adjustment it requires, the less I'm a fan of it.
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Again, not dismissing the whole inside-leg-for-groin thing, it's just wouldn't be my go to if I was worried about violent assault, and groin kicks were an integral part of my self-defense repertoire.
For the record, I actually spend very little time worrying about groin kicks, they drop some guys, they take a while on others, and some guys can tough it out for a bit. Nobody can run fast with a knee that's not functioning, punch hard with a dead elbow, or do much of anything with a brain that decides it's nap time.
Definitely a fan over structural damage and/or functional disruption over pain compliance. And yes, I would consider groin kicks to be more about pain compliance than anything else...