Back in like the Colonial era, the Victoria Era, Napoleonic style warfare when humans first started using firearms, and would like up and shoot until the officer yelled "fix bayonets" and "Charge", I imagine there was more real H2H as a huge part of the battle. How did they prepare soldiers back then for this?
During the American Civil War, I am sure they must have charged the enemy lines quite a bit. Did the forces do something similar to LINE or was it more realistic?
I think the LINE training is realistic for it. During a charge, if you are standing long enough to do martial arts moves, you are probably dead by gun shot anyway. One of the main reasons numbers are so important in a battle is that you are more likely to kill someone at an angle to you than someone right in front, and so on, so the side with more guys has unengaged flankers automatically.
What you want is everyone to run up, with the lead guys having the duty to catch bullets for the men behind them, and the next guys to immediately go for the kill and then continue the fight beyond.
The basic logic of sparring is self preservation. It is hard to spar balls out, two men going for the kill right away. If people are too trained, you have fucking around, standing there parrying and shit, which just won't do.
Look at it like this: the charge is declared either when you are sure it will succeed because the enemy is breaking, or when you are about to die anyway. In either case, there is no value in the men doing anything other than immediately going for the kill. You have to cut the other side's numbers down right away and take advantage while you have advantage.
That's how I understand it.
What produces this ability is the courage and willingness to take action and then carry it through to the end, no matter what happens. Education isn't always the best for that. Powerful belief in your ability to kill is good though. Think about TMA guys who never spar but are sure they could fight. It is kind of laughable.
Now switch it, and put yourself against worse than 1:1 odds, your ears are ringing from a grenade, there are no friendlies on your left hand side, and all those TMA guys come running at you with spears. That's fucked. Especially if they are as strong and fast as you.
TMA guys always claim their methods come from the military - well that is why.