- SpongeBob SquarePants
- Sandy Cheeks
- Gary the Snail
- TV shark (debut)
- Squidward Tentacles (cameo)
- Eugene H. Krabs (cameo)
- Larry the Lobster
- Weightlifter (debut)
- Trainer (debut)
- Blue muscular fish (debut)
- Sports guy
- Hot dog vendor (arm only)
- Anchor distance measuring fish (debut)
- SpongeBob/Sandy fans
- Other muscular fish
SpongeBob starts his day off by posing in front of a mirror as he gets ready to make himself "large and wide." He goes to his stuffed animal barbell weights, and with great effort manages to lift them over his head, only to fall down. Just then, Sandy comes inside and SpongeBob shows off his stick arm "muscles," bragging about his "state of the art weight set." However, Sandy bluntly tells him that he is not going to gain any muscle mass unless he starts using her own personal training program. SpongeBob is ecstatic, imagining himself in various situations - flipping burgers, jellyfishing, and sleeping - with a bodybuilder's physique, and agrees to come to Sandy's treedome at 5 AM to begin his new workout.
At the treedome, SpongeBob is put through a progressively intense series of warm-up exercises from push-ups to boxing to running on a giant hamster wheel, each resulting in his arms separating from his body. Sandy now takes the less than enthusiastic sponge to the "arm cruncher," to which the sight of the contraption drives SpongeBob away, only leaving a phone in Sandy's grasp. Back home, SpongeBob is despondent and in pain at how difficult working out actually is until a voice addresses him from the TV, calling him a wimp. It is a commercial for the Anchor Arms, a set of inflatable muscle balloons with options ranging from normal to "veiny," and "for the ladies... hairy!," with the shark demonstrating its uses. Gary meows skeptically, but SpongeBob is interested and goes to buy some.
Later, while wearing the Anchor Arms, SpongeBob heads towards Mussel Beach, freaking out everyone else along the way. Once he gets there, everyone is awestruck by "MuscleBob BuffPants," and follows him to the Juice Bar. Sandy comes along asking where SpongeBob is and finds him surrounded by his new fans. A short moment where SpongeBob cannot move his drink reveals the downside of his Anchor Arms: because the "muscles" are just air inside an arm-shaped balloon, he is still a weakling, but manages to avoid detection by sipping the straw from a distance. Sandy is naturally confused as to how he managed to gain muscles so quickly, to which SpongeBob replies that he found his own secret workout. Intrigued, Sandy asks what the secret was; putting SpongeBob on the spot as everyone else also wants to know.
SpongeBob manages to fool them by claiming armpit farts are his secret workout, pushing aside skepticism by pointing out the results. Everyone else promptly begins armpit farting, while Sandy congratulates SpongeBob for finally finding a workout that works for him. To SpongeBob's surprise, she then suggests he needed to put those muscles to the test, and it just so happens the Anchor Toss Competition is today. Completely caught off guard, SpongeBob doesn't notice a drink being placed on top of his Anchor Arms and tries to tell Sandy he is not interested, but she decides to go sign them up anyway. Scared of being exposed, he tries to stop her but finds himself pressured down by the drink. The panicking SpongeBob finally catches up to Sandy after the waiter takes the drink off of his hand, sending him flying into the pole next to her. Unfortunately, Sandy has already signed them up, and there's no turning back.
At the Anchor Toss, everyone is preparing themselves, except for the worried and unsure SpongeBob. He nervously says he is ready when Sandy comes by to check, but quickly begins inflating more into his Anchor Arms in desperation when she turns away. Perch Perkins announces the start of the 8th Annual Anchor Toss Competition, with Don the Whale making the first toss. His anchor lands at 200 yards, with an "instant replay" crushing the helpless measurer. Next up is Larry the Lobster; the measurer, not wanting to be crushed again, tries to run out of firing range, but the anchor tracks him and crushes him at 210 yards. Sandy is up next, and launches her anchor with her signature karate kick; the measurer desperately tries to outrun the anchor but is hit at 510 yards, putting Sandy in the lead.
It's finally SpongeBob's turn, with the crowd chanting his name as they do his armpit farting workout. SpongeBob tries to lift the anchor, but only manages to pull it on top of himself. He manages to pass it off as a joke, but knows that he can't keep the charade up; he is going to be exposed as a phony. However, he decides he has to try anyway and blows his arms up to the "jerk" size, apparently breaking them. He puts all of his might into lifting the anchor, but all it does is push the air into various parts of his body and eventually the Anchor Arms explode out of overinflation, revealing SpongeBob to be a weak fraud. Upon realizing this, the crowd exclaims that he lost and start cheering for Sandy, since she won. Sandy herself is very disappointed in SpongeBob's revelation, tapping her feet expectantly; SpongeBob gets the hint, realizing there's no substitute for hard work and trudges after her.
The episode ends back at the treedome, as SpongeBob's new exercise is changing the TV channel 100 times with his thumb, much to his discomfort. Sandy figures they have finally found an exercise that works for him right before SpongeBob's arm falls off again, and he asks if she could pick it up.
- SpongeBob's arms keep detaching from his body after one of Sandy's workout routines.
- SpongeBob being unable to lift light things like a glassful of drink.
- The measurer getting crushed by the anchor.
|( ‣ ) Associated production music|
|( • ) Original music|
|( ◦ ) SpongeBob music|
‣ Big Ed's March - Sam Spence [title card]
‣ Chief Taravana - Kapono Beamer [SpongeBob flexing]
‣ Grand Orchestral Fanfare - Gregor F. Narholz [SpongeBob lifting weights]
‣ Timpani Roll - Sammy Burdson [SpongeBob lifting weights]
‣ Chief Taravana - Kapono Beamer [Sandy at the door]
‣ Music, Box - [General Series 6000 Extension] [stuffed animals]
‣ Chief Taravana - Kapono Beamer ["I don't wanna disappoint you, SpongeBob, but you won't see any progress with those."]
‣ Vibe Link (a) - Richard Myhill [Start of SpongeBob's daydream]
‣ Pell-Mell - Sam Spence [SpongeBob trying to do push-ups]
‣ Dramatic Impact 5 - Ivor Slaney [arm cruncher]
‣ Hawaiian Link (b) - Richard Myhill [SpongeBob in bed]
‣ Fun at the Seaside - Syd Dale [Anchor Arms commercial]
‣ Constant Menace - John Fox [SpongeBob walks past Squidward and Mr. Krabs]
‣ Stars and Games - Alf Saro [Mussel Beach]
‣ Polynesian Adventure - The Mel-Tones [at the juice bar]
‣ Vibe Link (b) - Richard Myhill ["What do you mean?"]
‣ Mavericks - The Woodies ["Wait, Sandy!"]
‣ Rocket Sled to Oahu - The Mel-Tones ["Oh, great. Thanks, Sandy."]
‣ Hero of the Beach - The Surfdusters [anchor toss competition]
‣ Hawaiian Link (a) - Richard Myhill ["Oh, this is it."]
‣ Big Ed's March - Sam Spence [SpongeBob inflates arms]
‣ Hawaiian Link (b) - Richard Myhill [SpongeBob laughs nervously]
‣ Fun at the Seaside - Syd Dale [ending]
*On The Complete 1st Season, Home Sweet Pineapple, and The First 100 Episodes DVDs, "Mavericks" is replaced with "Rocket Sled to Oahu" by The Mel-Tones while the Amazon Prime Video version has the "Mavericks" music left intact.
- This episode is available on The Complete 1st Season, Home Sweet Pineapple, Karate Choppers, Beach Bob, The Ultimate Box Set, Sportingly Sandy, First 100 Episodes, The Super Celebrations, Exposed!: The Ultimate Box Set, The Ultimate SpongeBob Box Set, SpongeBob SquarePants Vol. 1, Employee of the Month, The Complete First Season, From the Beginning, Part 1, The SpongeBob SquarePants Collection, Deep-Sea Games, The SpongeBob SquarePants 8 Season DVD Collection, Triple Pack 4, The First & Second Seasons, Movies & TV Collection, Big Hits: Volume 2, and The Best 200 Episodes Ever DVDs.
- This episode is also available on the UK version of the Home Sweet Pineapple VHS tape.
- "MuscleBob BuffPants" was ranked #72 during the Best Day Ever event from November 9–10, 2006.
- "MuscleBob BuffPants" was ranked #9 during the SpongeBob's Top 100 event in the UK and Ireland from June 4-8, 2012.
- Moral: You don't have to be strong to impress someone, just be yourself.
- This episode was formerly called "Pump It Up."
- The shark in the commercial for Anchor Arms breaks the fourth wall when he says "Hey, hey you!" in the first part of the commercial. This means he was talking to the people who were watching the TV, but also to SpongeBob.
- The billboard sign with beachgoers working out reads "Mussel Beach" instead of "Muscle Beach." This is a reference to the tiny shell-covered creatures commonly found on beaches.
- Tiny Tim is referenced in this episode when SpongeBob says "Who were you expecting, Tiny Tim?" He is the singer of "Livin' in the Sunlight, Lovin' in the Moonlight," which was used in "Help Wanted."
- In March Toon Mania, the narrator claims this as "The Chaperone."
- The Juice Bar in this episode is later seen in the video games Battle for Bikini Bottom and Battle for Bikini Bottom - Rehydrated in the Goo Lagoon area. It was also seen in Lights, Camera, Pants!, SpongeBob Moves In!, SpongeBob: Krusty Cook-Off and Nickelodeon Kart Racers 2: Grand Prix.
- Anchor Toss scores:
- Sandy Cheeks: 510 yards (466.344 meters) (winner)
- Larry the Lobster: 210 yards (192.024 meters) (second place)
- Don the Whale: 200 yards (182.88 meters) (third place)
- SpongeBob SquarePants: 0 yards (000.000 meters) (loser/disqualified)
- Larry's grunt when he threw the anchor was played by Bill Fagerbakke instead of Doug Lawrence.
- Frank is another competitor in the Anchor Throwing Contest, but does not get a chance to throw his anchor.
- Sandy technically didn't throw her anchor like the others; she just threw it in the air and kicked it when it came back down so her throw would have resulted in a disqualfication.
- In the scene where the Anchor Arms blow up, they are then deflating in a similar manner as a rubber balloon: floating randomly as they lose air and making a characteristic noise.
- Sandy seemed to have won the contest, beating Larry. However, in "Ripped Pants," Larry seems to be stronger than Sandy with weight lifting.
- The Anchor Arms are later used by the SpongeBot SteelPants in the 2003 video game Battle for Bikini Bottom and the 2020 video game Battle for Bikini Bottom - Rehydrated after it is defeated by the player and before SpongeBob enters its head.
- In the Polish dub, the title for this episode is "PakerBob Mięśniakoporty," which translates to "Body-Builder Bob Muscle Pants."
- The plot of this episode is similar to that of "Ripped Pants." In both episodes:
- SpongeBob tries to do something to impress Sandy.
- Everyone starts liking him.
- A mistake happens that leaves SpongeBob exposed and not loved anymore.
- The ending reveals Sandy likes SpongeBob just the way he is.
- Both episodes take place at Goo Lagoon.
- According to The Ultimate SpongeBob SpongeBash, Jerry Trainor ranked this episode as his favorite.
- Some clips of this episode are shown in the 2008 film, Cloverfield.
- Scooter mentions the episode's title when he says, "You mean MuscleBob BuffPants? He's in there."
- This is the first episode to use the track "Pell-Mell"
- Anchor Arms is a reference to part of an anchor called the "arm," which is the part that curves out from the bottom end of the main part and ends in the pointed part.
- When Sandy helps SpongeBob exercise by performing push-ups, the rim of SpongeBob's water helmet is transparent.
- While Mr. Krabs was sweeping in front of the Krusty Krab, his head overlaps with his shirt. Also, one of his sleeves is transparent.
- At the beach, SpongeBob somehow has white sleeves even though he is wearing a bathing suit.
- When Sandy is signing SpongeBob up for the anchor tossing competition, she doesn't put a space between his first and last name.
- When SpongeBob hits the pole after Sandy finishes signing him to the anchor toss competition, he is in his normal clothing instead of his speedo.
- Before trying to lift up anchor, SpongeBob has to blow into both of his anchor arms to inflate them, but he only blows into one of them to do so both when it was his turn. This also applies when he over-inflated them into the JERK size.
- When SpongeBob inflates the fake arms and the inflation meter is shown, the "Veiny" and "Hairy" settings mentioned earlier are not on the meter.
- The over-inflated Anchor Arms explode after SpongeBob's last attempt to throw the anchor. However, the popped remains of the fake arms are shown deflating with air coming out of them instead of being completely destroyed. Also, the pressure of the explosion didn't harm SpongeBob anyways, as he still stands on the spot where his fake arms exploded.
- In the final scene, SpongeBob doesn't have a left arm.