"The Strong Arms of The Ma" is the ninth episode of The Simpsons' fourteenth season. It is also the 300th episode of The Simpsons in production order. In broadcast order, "Barting Over" is the 300th episode while "Strong Arms of the Ma" is the 298th.
The Simpson family goes to Rainier Wolfcastle's Bankruptcy Garage Sale, where everything that he owns is up for sale at throwaway prices. Homer asks Rainier if he has anything that will go up in value when he dies and is shown his old weight-lifting set, complete with dumbbells and bench press. Homer takes it and packs everything in the car in the style of a Tetris game. The car ends up being so overpacked that Homer ends up being carried home by Rainier Wolfcastle in an adult sized baby harness built for an adult.
On the way home, Marge and the kids smell something awful. They pinpoint the source to Maggie. Marge quickly pulls into the Kwik-E-Mart, and Apu is reluctant about letting Marge use the restroom, but when he smells Maggie, he allows it. Later, as Marge comes out with a much sweeter-smelling Maggie, a shady character in a Goofy hat accosts her and threatens her with a gun. Finding only diapers in Marge's purse, he grabs Marge's pearl necklace and takes off. Marge, stunned, walks to her car in a daze and breaks down sobbing at the wheel in front of her kids.
The next day, the family inform the cops and Chief Wiggum declares he will get on it right away. Later, as Marge is about to leave the house, Homer gives her some pepper spray and some tips on how to handle an attacker. She pulls up to the Kwik-E-Mart, but she is scared when Ralph greets her. She pepper-sprays him, and feeling guilty, she drives back home where it's safe.
The rest of the family discovers Marge is a nervous wreck and cannot bring herself to cross the threshold of her house. Homer and the kids try their level best to encourage her to go outside, but to no avail. Finally, she moves into the basement. There, feeling a bit safer, she prepares breakfast for the family and sets up a bed for herself. One day, when she is alone at home, feeling bored but still afraid to venture outside, she eyes Rainier Wolfcastle's weight-lifting set and decides to use it to pass the time.
In two weeks, she builds herself up and even gets a well-defined washboard stomach (much to Homer's delight). Suddenly, she dashes out to the garden to get some lemons. Realizing that she is not afraid anymore, an overjoyed Marge starts running around town. Suddenly, she runs into her mugger, who sarcastically says "What you have done, living with fear?" (as Marge joyfully remarks that she is not afraid any longer to everyone that she sees ahead.). Even though the mugger does not move a finger against Marge, she beats him to a bloody pulp out of revenge. Homer gleefully declares "It's like I'm married to Shaft!" The cops arrive and arrest the crook.
Marge starts exercising even more. One day, as she jogs by an open-air gym at the beach, she runs into Ruth Powers, her old neighbor (from "New Kid on the Block" and "Marge on the Lam"). Ruth, pretty buffed herself from her years as "Miss Mexican Mafia" in prison, tells Marge that she owes it all to steroids. She talks Marge into using them, attacking her inability to stop trying to be stronger, and also advises Marge to enter a women's bodybuilding contest. Marge, using the steroids, exercises harder than ever, and becomes very muscular and estrogen-depleted, resulting in a short temper and a new-found violent streak, which is quite harmful to everyone (including her family) next to her, especially due to her recent developed superhuman strength (evident when she stop and lifted the school bus with her bare hands). Homer, seeing these changes, finds himself less attracted to her. When Homer refuses Marge's sexual advances the night before the contest, she callously ignores his worries and then proceeds to pin him down and rapes him, before leaving him completely sore and exhausted to take care of the kids the next morning. When Bart asks why didn't Marge make their lunches, Homer replies that "Your mom has a lot of stuff to shave.".
That night, the family attends the Springfield Women's Bodybuilding Finals. Marge wins second place, which irritates her when her muscular ears overhear her family's unhappy conversation in the audience. Later that night, at Moe's, Marge boasts to the all male attendees about her performance at the competition. Homer tells her he is proud of her that she managed to bulk up but not lose her femininity. Marge, angered by that, says that was the reason she came in second place. She than tells everyone at the bar that starting tomorrow she was gonna up her glycol-load, use a denser ripping gel, and claims that she didn't "sacrifice her period to come in second place."
Things get worse when Moe says to Marge that "I don't got enough booze to make you look good". She flies into an uncontrollable rage, beating up all comers (even taking out five sailors as they march in to fight her) and ultimately trashes the bar. Homer (who has been hiding in the bathroom) comes out to confront his wife as she prepares to hurl Lenny. Terrified, Homer tells Marge that he misses the sweet, feminine woman he married. Marge, horrified with what she has done, apologizes, drops Lenny, and leaves with Homer. Moe, in order to cover the costs of repairing his bar, sets fire to it; however, Carl points out that he has not insured the place yet.
Later, at the Simpson house, Marge burns the weight set in the furnace as the show ends. Homer asks if Marge is ready for a "real workout" which turns out to be a request to wax the car, after which he gets beaten by Marge into meekly saying that he was just kidding.