"ground the spear and receive a charge" is spear knowledge 101 in HEMA communities. A butt-spike helps.
It works so well that you're generally not allowed to do it in the full contact rulesets, because it's counterproductive to break your opponents today; you can't fight them tomorrow!
Not to argue with anything, but after observing it for a while, I cannot treat HEMA seriously. And this is true about most of the "reconstruction" stuff. The problem is, that guys who "do" it are almost exclusively not the guys who would participate in city-level wrestling or even powerlifting competition. To say it bluntly, most of them don't have the most basic fitness level.
The point of that entire activity is to learn by experience what is doable/not doable with some historic tools, and hence derive, how these tools were probably used. But their learnings aren't very valuable, since it's pretty evident they aren't anywhere near of strength and coordination of a trained person. I would bet a fucking (professional) figure skater would beat them with a stick.
And this is super important, because the supposed original users of a given tool are almost exclusively supposed to be people trained to wield it daily from the childhood. Not to mention they wouldn't spend much time in front of a monitor ever.
It works so well that you're generally not allowed to do it in the full contact rulesets, because it's counterproductive to break your opponents today; you can't fight them tomorrow!