Joshua Horns is a grad student at the University of Utah Biology Department and he was working on a study about aggression and human evolution.

And one thing he needed to look at is how we punch, what the hand does when we punch.

So Joshua, what did you do?

We wanted to see our hands, when you put them into this buttressed fist that we can make. Does that mean that we can strike hard

without hurting ourselves? That's kind of what we wanted to look at. But this isn't really

a study you can do in live humans. You can't really measure how much

or how much strain there is in their bones because people really don't like you cutting open

their hands.

So we had the idea of using canabar arms,

where we would manipulate them into different hand postures,

and that way we could take recordings

from the bones in the hand and see how much force they were feeling, how much strain they were feeling.

Wait, so are you, are you actually taking human cadaver arms and making them punch things?

Yeah, that's right.

So then what did you hit with it?

So the arm, once it was in the correct confirmation, that sat on a pendulum and we pulled

the pendulum back and let it swing down into a weight. It made contact with the weight at the

bottom of the swing when all of its velocity was

horizontal.

So we were able to get these simultaneous recordings of how hard the hand was hitting,

then how much strain, how much the bones in the hand were changing shape.

So did you, how many arms and fists did you have?

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