In standard olympic style wrestling they call it the ball and chain (well, a variation of it) but it's only used for when someone goes to their stomach (that is, gives you the back, which a good ground fighter will never do) so that seems to limit it's effectiveness. As to a standing pump handle...well, I dunno. Like you said, the set up would be ridiculously hard, but theoretically possible.
I don't know about MMA, but I have a pretty funny story about using the "pump handle" being part of my old TMA's curriculum.
One of the quirky things about the American Kenpo that I've never been able to understand is that Ed Parker devoted 4 self-defense techniques to the deadly and dangerous "unfriendly handshake attack". The names of these techniques all have the word "gift" in them in order to symbolize the handshake. There is "Gift of Destruction", "Gift of Destiny", "Gift in Return", and "Broken Gift".
"Gift in Return" involves ramming your "attacker's" hand back into his groin, swinging around behind him, getting him in a "pump handle, and then kneeing him in the ass.
Here is a technique description I found on an American Kenpo website.
This description says to knee the back, but I distinctly remeber the intended target being the tailbone.
GIFT IN RETURN
Defense against an unfriendly handshake
Pin attackers hand with your left hand as you step forward to 10:30 with your left foot and Push Drag into a left High Wide Kneel while driving grabbed hands into attackers groin. Keep your face to the left side of their shoulder to avoid a head butt.
Step to 12:00 with your left foot (slightly behind attacker) as your left hand reaches under attackers legs and grabs attackers right wrist. Step back to 10:00 with your right foot and grab attackers belt with your right hand. Pull attackers hand with your left hand while you push on their lower back/hip with your right hand.
Do a right Step-Thru Side Kick to the back of attackers left knee as you let go of their right hand.
As you land from the kick, do a left knee to attackers back and cover out.
Main Power Principle
One of the big reasons I don't do American Kenpo anymore.
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