Emperor Evulz comes up from behind and grabs Alice's arm. Since she is wearing an electric taser glove, Evulz ends up getting electrocuted and falls.
Alice is an energy stealer, and can never be with Bob without killing him because she drains anyone who touches her. Evulz is used to demonstrate this.
Gender Inverted: Bob is kicking ass, until Emperor Evulz comes up from behind and grabs his arm. He starts screaming for Alice's help.
Subverted: As Evulz grabs Alice's arm, she judo flips him over. When he's on the ground, she stomps his groin and says, "You really thought that would work?"
Double Subverted: After Alice judo flips Evulz, he grabs the other arm and flips her over, pulling himself up at the same time. "Yes."
Parodied: All women have this weakness, and so they wear armor on their upper arms.
Zig Zagged: Emperor Evulz grabs Alice's upper arm and she becomes helpless. But as he starts dragging her to his helicopter, she knees him the groin and is able to make a mad dash for the battle field again. THEN, a Mook grabs both her arms and she is rendered helpless again.
Nobody ever tries to grab Alice by the arm.
Whenever someone grabs Alice by the arm, she easily pulls away.
Enforced: The writers may feel- or may have been told- that other ways of subduing a female character (like a "full nelson") are too graphic or sexual to portray (as, for example, a man would have less latitude with what areas of a woman's body he can grab without it being considered sexual), so they resort to this move as a compromise.
Lampshaded: Alice is grabbed and complains of how she can never fight when that happens.
Invoked: As Alice and Evulz face off in a rather impressive fight scene, a Mook calls out "Grab her arm!"... and it works. Bob to the rescue!
Exploited: Alice lets herself be grabbed by a misogynist and Wrong Genre Savvy villain in order to get inside his lair and destroy it from the inside.
She took up Judo for just such an occasion.
"Why are you wearing spiked armbands?"
Discussed: "AH! Bob! Help me!" "What? You can fight a dozen ninjas with your hands tied, but you can't shake off a man who's grabbing your arm? Sheesh..."
Conversed: "Odd. Most villains would grab her by the arm instead of kicking her in the groin."
Implied: Alice has already been imprisoned. Her captor boasts on how easy he kidnapped Alice just by grabbing her arms.
Deconstructed: Due to this, women are not allowed to fight unattended or without a male escort no matter how tough they are.
Reconstructed: In the world the protagonists live in, 90% of the ostensibly female population are RobotGirls who have a disabling switch on their arms.
Played For Laughs:
Emperor Evulz knows no less than 56 methods of paralyzing a woman through just the nerves on her upper arm: All the better to capture princesses with!
Jake is grabbed in this spot by Evulz, and collapses into an exaggerated dead faint.
Played For Drama: Alice is riven with self-loathing due to the fact that for all her skill, she can never free herself from this maneuver.