[[quoteright:320:[[Anime/FullmetalAlchemist http://static.tvtropes.org/pmwiki/pub/images/fma_armstrong_rally.jpg]]]]
[[caption-width-right:320:[[MeaningfulName Armstrong's]] [[CatchPhrase physique has been passed down the Armstrong line for generations!]] [[ComicallyMissingThePoint Would you doubt a man with muscles this large? FEEL!]][[note]]BishieSparkle included.[[/note]]]]

->'''[=LaBarbara=]:''' You can't argue with those luscious pecs! \\
'''Hermes:''' No I can't. But I can ask him to stop wiggling them in my face! \\
'''[[TheAce Barbados Slim]]:''' I'm not wigglin' dem. Dey do dat by demselves.
-->-- ''[[WesternAnimation/{{Futurama}} Bender's Big Score]]''

Similar to {{Gainaxing}}, where a male character's pectoral muscles jiggle and bounce, except that they flex them to make it happen. However, generally it is used not so much for {{Fanservice}} as it is used as an [[TestosteronePoisoning often comedic]] demonstration of "manliness". Other names for it are the "Pec Bounce", the "Pec Dance" (usually this name is used if people flex their pecs in time to music), and the "Pec Pop".

Another variant is the "Ab Wave", where a character with a well defined six pack will flex their stomach muscles like a wave. Generally, this isn't so much saying "look how strong I am" as it is "aren't I sexy?"

For cases of Pec Flex when the flexer has less than impressive pecs, see FlexingThoseNonBiceps.

* Not surprisingly, this is part of the act for the Happy Bodybuilder Directing Traffic in [[http://www.youtube.com/watch?v=TBSt1CtJEOk this]] GEICO commercial.
* This also happens in one Fruitsnackia commercial (to be more specific, [[http://www.youtube.com/watch?v=pjLuzKdCQs4 the wrestling commercial.]])
* If Creator/TerryCrews appears in an [[Advertising/TheManYourManCouldSmellLike Old Spice]] [[http://www.youtube.com/watch?v=fXvtany3mSE com]][[http://www.youtube.com/watch?v=_fNYFp1VCX8 mer]]cial, expect this to happen.
** Pretty much Creator/TerryCrews [[http://www.youtube.com/watch?v=oNf606dfCb0 does]] [[http://www.youtube.com/watch?v=58uadqTQNGY this]] [[http://www.youtube.com/watch?v=aIstFQqRLiA in]] [[http://www.youtube.com/watch?v=ckwug3y0ucA general]].
* This also happens in a [[http://www.youtube.com/watch?v=1R_jwF7xqJE Brazilian Doritos commercial.]]
* Happens in a personalized [[http://www.youtube.com/watch?v=VBbPh5G7iMc Valentines M&M commercial]] where a guy tattoos his pecs to have him and his girlfriend on his pecs.
-->"Look! We're dancing!"
* This also happens in a [[http://www.youtube.com/watch?v=oSFnotAmcoA Boost Mobile commercial]] of Travis Barker.
* Happens in an Indonesian commercial [[http://www.youtube.com/watch?v=wFu-B-6QEE4 for an energy drink with milk.]]
* [[http://www.youtube.com/watch?v=0RcxqzjNW7g A bodybuilder in a cow suit]] does this in more than one Applegate hot dog commercial.
* Gary Lineker does this in a [[http://www.youtube.com/watch?v=R2phBjlUMTg Walkers Max potato chip commercial]].

[[folder:Anime & Manga]]
* In [[Anime/{{Pokemon}} the Pokémon anime]], the obese Gligarman's chest shakes in surprise. [[FanDisservice Homina homina--NO.]]
* Alex Louis Armstrong of ''Manga/FullmetalAlchemist''. It has been '''♥♥♥ [[LargeHam PASSED DOWN THE ARMSTRONG LINE FOR GENERATIONS]]! ♥♥♥'''
** He befriended Sig Curtis, Izumi's husband, through a flex-off. It was [[CrowningMomentOfFunny bloody hilarious]]. And it was followed by [[SugarWiki/MomentOfAwesome BLOODY AWESOME]]!
--->''"Valor a hundredfold~! Muscle a thousandfold~!"''
** Speaking of Curtis, his Pec Flex was so epic his shirt ''exploded''.
* Jack Rakan of ''Manga/MahouSenseiNegima''. At one point, he even uses it to [[spoiler: completely shatter a PocketDimension]].
* Gateau Mocha in ''Manga/SorcererHunters'', constantly. Especially in the manga.
* Being [[ImprobablyFemaleCast one of the manliest characters]] in ''Franchise/LyricalNanoha'' at the time, FanWebComic ''[[http://ashitahadocchida.sakura.ne.jp/strikers_nano.html StrikerS Nano]]'' had [[http://img41.imageshack.us/img41/2255/strikersnano161tr.png this as part]] of the RunningGag character trait of Zest.
* In ''Manga/YowamushiPedal'' Izumida does this often, which he shockingly names it Andy and Frank [[spoiler: During the faceoff with Hakone Academy]]
* In ''Manga/{{Bleach}}'', [[BloodKnight Ikkaku Madarame]] gets his shoulder dislocated in a fight. He immediately [[RatedMForManly does a Pec Flex so epic it resets his shoulder]].
* In ''Manga/FistOfTheNorthStar'', Kenshiro faces a sergeant warrior who wields strange straw weapons that quickly suck all the blood out of their victims. Kenshiro nonchalantly lets himself get impaled by about 8 of them and shows off by flexing so epically that the straws stop draining and pop out of him.
* In ''Anime/MobileFighterGGundam'', just doing this was enough for [[spoiler:Colonel Ulube]] to deflect Chibodee's ultimate technique, the Bursting Machine-Gun Punch.

* "LightNovel/{{Slayers}}''
--> ''I wanna do that! But I can't!"
** It is worth mentioning that this line appears when Lina Inverse sees the "Dragon Blood Macho Battlers". A gang of bandits whose STANDARD GREETING apparently is to flex and twitch their pecs.

[[folder:Films -- Animated]]
* This is done by Young Macintosh in ''{{WesternAnimation/Brave}}'', in his attempt to impress Merida during the suitor presentation.
* In ''Disney/{{Moana}}'', Maui does this at the beginning of his IAmGreatSong. Even better, he flexes each pec one after the other, bouncing his AnimatedTattoo across his chest! "''I know it's a lot, the hair the bod / When you're staring at a demigod!''"

[[folder:Films -- Live-Action]]
* Comes up in ''Film/SpiceWorld'' during a video shoot [[http://www.youtube.com/watch?v=x0uXpm41seA involving a lot of buff men.]]
* [[Wrestling/DwayneJohnson Dwayne "The Rock" Johnson]] also does this a few times, like in ''Film/TheGamePlan''.
** [[http://www.youtube.com/watch?v=apQPaduDRVw He also does it in]] ''Film/Journey2TheMysteriousIsland''.
* Used as an intimidation move by one of the contestants in ''Film/BallsOfFury'' (who happens to be Creator/TerryCrews).
* ''Film/DrunkenMaster'', Jackie Chan's 1978 film in which Jackie played a young troublemaker. At that point on the run from a promised brutal disciplining at the hands of an uncle he's never met, he scams a local restaurant. Jackie's character attempts a dine and dash, but the restaurant has a bouncer who easily blocks the way. The bouncer takes his title seriously, by bouncing his pecs to intimidate customers he intends to throw out.
** 'I am Iron Gorilla. See me jump.'
* In one scene from the very very early Creator/ArnoldSchwarzenegger movie ''Film/HerculesInNewYork'', the titular Herc manages to ''alternate'' flexing each pectoral muscle. It can be seen in [[http://www.youtube.com/watch?v=NaZmYuSniVU this video]] at the 0:17 mark. He also did it in an outtake of his documentary-- "Pumping Iron".
** Similarly, ''Film/HerculesReturns'' (a comedy dub of ''Film/SamsonAndTheMightyChallenge'') [[http://www.youtube.com/watch?v=YuWxfvN5PRM contains the legendary line]]: "I'll fight you on one condition... that you lower your nipples." The opponent... does.
* In ''Film/OneHundredGirls'' the main bad guy does that in a very intimidating and unsexy way.
* [[https://www.youtube.com/watch?v=5oZfNkhqo3A David Fine does this]] in ''Her Minor Thing''.
* [[https://www.youtube.com/watch?v=GwpAG6mpvCI Bob Sapp does this]] in ''Big Stan''.
* Hilariously done by an old guy in ''Film/MyFavoriteMartian'', while "Hot Hot Hot" plays in the background.
* Done by Chong Li, the BigBad of Film/{{Bloodsport}} as a way to intimidate his opponents before a fight.

[[folder:Live Action TV]]
* ''Series/{{Supernatural}}''. [[http://i48.tinypic.com/e0hjqw.gif Sam Winchester]], season one, episode seventeen. You're ''welcome.''
** ... It looks like... it's winking.
* A Charles Atlas parody in ''Series/MontyPythonsFlyingCircus''.
* On ''Series/{{Scrubs}}'', the [[AlmightyJanitor Janitor]] claims that [[http://www.youtube.com/watch?v=ZRNhcuhIpko he ran into J.D. encouraging a muscular guy to do this]] is what made him suspect he was gay. Being a consummate liar, the ImagineSpot story is complete fiction.
* John Enos does this five times in four separate episodes of ''truTV Presents: Series/WorldsDumbest'' He usually does it when he has his [[ShirtlessScene shirt off]].
* Music/BritneySpears is shown doing it during a sketch when she hosted ''Seres/SaturdayNightLive''. In reality, she had a device under her top to make them go up and down.
* From Opportunity Knocks, we have [[http://www.youtube.com/watch?v=OxLk-WHnMCs Tony]] [[http://www.youtube.com/watch?v=A6PNomWvcrg Holland]], who won for 6 consecutive weeks by doing this.
* Dylan Yeandle [[http://youtu.be/lE6sOcxlb9w?t=1m53s does this in the Semi finals]] of Australia's Got Talent.
* Two men [[http://www.youtube.com/watch?v=Rr_e0S5nJkk did this as their act]] on Series/AmericasGotTalent.
* [[http://www.youtube.com/watch?v=MgyFpVY3EGE Blake Jenner does this]] in the sneak peek of the of the ''Series/{{Glee}}'' episode, "Naked".
* Pete Lattimer from ''Series/{{Warehouse13}}'' rarely misses a chance to doff his shirt and pop his pecs. He once did so without prompting in front of newly-arrived gay Agent Jinks, along with comments on how glad he is to have someone around to appreciate his body and an offer to strip anytime Jinks wants.
* From ''Series/{{Bewitched}}'' season 5 episode 22 "Going Ape" Happens when Miss Tucker come into Mr. Tate's office to advertise her new "Brawn Cologne" with muscle men to use in the commercial.

* Approximately 30 seconds into the music video for Music/{{Rammstein}}'s Mann gegen Mann.
* Done approximately 1:27 in the {{Music/LMFAO}} music video of Sexy And I Know It.
* Demonstrated in the video for Music/JoanJett's "Do You Wanna Touch Me." Not demonstrated by Joan, sadly.

[[folder:Professional Wrestling]]
* Done often in ProfessionalWrestling, usually right before a match begins or right after executing a really awesome move.
** Wrestling/LexLuger was one of the most frequent practitioners. Chris Masters did this as much, if not '''more''' than Lex Luger.
** Wrestling/BrockLesnar, Wrestling/ScottSteiner, and Wrestling/{{Batista}} also did this.
** Frequently doen by Tony Atlas back in the 80's.
** Wrestling/WadeBarrett does it in the Season 1 finale of ''Wrestling/{{WWE NXT}}''.
** Wrestling/HulkHogan does it during his posing after the main event of the first Wrestling/WrestleMania.
** Wrestling/RonSimmons (back when he was Faarooq) once intimidated an interviewer by simply looking bored and ''standing still and doing this''.
** Elektra, a valet from the ''real'' Wrestling/{{ECW}}, used to do this. Yeah, it was {{Fanservice}}. Ostensibly it was to intimidate the other valets, though, since she always claimed she was [[HoYay more woman than they were]].
** See a few of these wrestlers' pec flexing abilities [[http://www.youtube.com/watch?v=nz33VkVvVDE here]].
* An episode of Wrestling/{{WWE}} Monday Night Raw featured [[Music/OzzyOsbourne The Osbournes]] as guest hosts, with a parody of ''America's Got Talent''. Chris Masters' talent? [[http://www.youtube.com/watch?v=sFLcacc0o6M Flexing his pecs to "Crazy Train".]] [[HilarityEnsues Hilarity ensued]].
** Wrestling/ChrisMasters also did that to the tune of [[Music/BlackEyedPeas Boom Boom Pow]] [[http://www.youtube.com/watch?v=sFLcacc0o6M in a different episode.]]
* On the US independent circuit, Chris Masters has a rivalry with Wrestling/CarlitoColon, and yes, it involves flexing, though Carlito's more defined in his abs and arms and thus loses in pure pectorals.
* This is Jesse "Mr. PEC-Tacular" Godderz's main gimmick.

[[folder:Video Games]]
* Slaking's Diamond/Pearl animation in ''Franchise/{{Pokemon}}'' has it Pec Flex. Of course, they don't necessarily have to be male....
** Machoke in Crystal, too. And Machamp in Black/White. Once again, one out of four is female...
** Buzzwole in Sun/Moon is even more flex-happy than the above. It even starts flexing when ''hurt''. Researchers in the Aether foundation theorize it has an entire language composed of different flexing poses.
* A VideoGame/SuperRobotWars 4koma parodying Ibis Douglas having the least bouncy chest in the series gets epically ridiculous when Sanger Zonvolt shows up barechested and does this trope after having already shown one of the bustiest characters in the series and a loli outdoing her.
* Super Macho Man from ''VideoGame/PunchOut'' introduces himself before a fight with a Pec Flex.
** [[http://www.pages.drexel.edu/~wmv23/supermachoman.gif He also does it when Mac is knocked down. And when he wins...]]
** When Mac hits the mat, it's difficult to get him back up: one would be too busy cracking up at S. M. M.'s little routine.
** [[http://www.yt2gif.com/view/143979 He steps it up a notch in the Wii version by doing just this before the match]], and turning around and [[{{Squick}} flexing his ass at the screen]] too.
* Zangief did it in several iterations of ''StreetFighter'', even the chibi-Zangief in Super Gem Fighter Mini Mix (or Pocket Fighter, depending on locale). And in ''VideoGame/StreetFighterV'''s story mode, he breaks a ''Psycho-powered sword in two'' just by doing this trope.
* VideoGame/LeisureSuitLarry can do this after hitting the gym (a lot) in ''Leisure Suit Larry 3''. The subtitle of the game is called [[AddedAlliterativeAppeal Passionate Patti in Pursuit of the Pulsating Pectorials]] after all.
* VideoGame/{{Undertale}}: Aron, one of the random encounters in Hotland, is a horse-headed monster who is always flexing. It's possible to end battles against him non-violently by [[spoiler: engaging in a flex-off with him until he flexes himself right out of the battle screen]].

[[folder:Web Original]]
* Website/GaiaOnline's Halloween 2007 vampire attack event had the Von Helson Twins ordered to kill Liam. Liam seduced the twins by flexing and spouting hilariously bad come-ons, which saved his life (and scored him a [[TwinThreesomeFantasy threesome]]) but left him a couple of [[StalkerWithACrush stalkers]].
* From the Planet Fitness Clunk-A-Lunk game, we have [[http://www.youtube.com/watch?v=pnplMuAIY4c Pecadoodledude]].
-->''Meet Pecadoodledude! You know this guy. He's the narcissistic nimrod who's always parked in front of the mirror, pausing between sets to lift up his shirt and peep his almighty pecs! He'll make 'em bounce! He'll make just the right one go! And then just the left! And then he'll juggle them back and forth! You'll wish that he'd knock himself out with one of his considerable chesticles! But he won't. He'll just keep checking himself out. So clunk away, my friend. Clunk away.''
** At least to this troper, it kinda sounds like the narrator keeps complimenting the guy.
* In [[http://www.youtube.com/watch?v=ILQS6MsB-mI this video]], two guys use this trope as a form of morse code.
* One guy turned this trope [[http://www.youtube.com/watch?v=V1v_7FFuLjM‎ into a language.]]
* Marc Lobliner from [[http://www.youtube.com/user/TheTigerFitness Tiger Fitness]] does this in almost every video.
* One guy [[http://www.youtube.com/watch?v=eR0WFsW9gj0 bounced his pecs to the Harlem Shake]] for about ''7 minutes.''

[[folder:Western Animation]]
* ''WesternAnimation/TheFairlyOddParents'':
** There are two characters that do this. Juandissimo Magnifico, Wanda's ex-boyfriend, does this along with his constant [[ShirtlessScene magic shirt ripping]]. Also, in the MadeForTVMovie ''Abra-Catastrophe'', Cosmo gains massive pecs from a workout video, and he Pec Flexes to absorb Crocker's magic.
** Who could forget Jorgen Von Strangle, toughest fairy in the universe. He loves to flex his muscles in the faces of anyone he can. He even refers to them as another sentient being (ex: "My muscles and I are still laughing!" Muscles: "Ha...haha...ha!"
-->'''Crocker''': Those are some massive pecs.
* WesternAnimation/JohnnyBravo can juggle with his pecs as a party trick.
* ''WesternAnimation/TheSimpsons'': Homer Simpson imagined himself doing this once while under the influence of Duff. Flexing them in time to the Can Can, too.
* ''WesternAnimation/AmericanDad'': Stan Smith did the same thing as well when he was celebrating.
* Lord Pain does this in ''WesternAnimation/TheGrimAdventuresOfBillyAndMandy'' to show off his tattoos of Grim right in front of him.
* An odd mechanical version done by Adonis in his PoweredArmor in the ''WesternAnimation/TeenTitans'' episode "The Beast Within", right after he knocks Cyborg out at the beginning of the episode.
* ''WesternAnimation/TimeSquad'': Buck bounced his pecs in a cartoon cartoon Friday crossover with Johnny Bravo.
* WesternAnimation/{{Futurama}} has Barbados Slim, and his luscious pecs. They apparently wiggle by themselves.
* Happens precisely once in ''Disney/MeetTheRobinsons''.
* Young Macintosh from WesternAnimation/{{Brave}} does this in his introduction [[http://www.youtube.com/watch?v=-MNbxXcQieY (here's the clip in question.)]]
* This happens a few times in ''WesternAnimation/RegularShow''.
** Twice in "Rigby's Body", once by the bodybuilder [[spoiler:that jumped into Rigby's body]] and again by Skips. ''His nipples light up.''
** Mordecai gets one too when he daydreams in "Meat Your Maker".
** The episode "Bald Spot" features Muscle Man doing this''as a plot point.'' Specifically, he kept flexing his pecs (which translates in this case to jiggling his manboobs) throughout the ''entire'' episode in order to distract Starla from his bald spot on his head.
** Rigby does this [[spoiler:after he gets buffed up]] in "One Pull Up".
** This also happens in two Cartoon Network bumpers of Regular Show where one's a fusion of [[http://www.youtube.com/watch?v=KQqRvfAmf1o Mordecai and Skips]], and the other is two clips of "Rigby's Body" with Skips and "Meat Your Maker" with Mordecai when he daydreams [[http://www.youtube.com/watch?v=tnvF9fJJLik back to back]].
* In the WesternAnimation/MyLittlePonyFriendshipIsMagic episode [[Recap/MyLittlePonyFriendshipIsMagicS4E10RainbowFalls Rainbow Falls]], Bulk Biceps does this between training sessions. [[{{GirlyGirl}} Fluttershy]] [[CoyGirlishFlirtPose seems to think it's cute]].

[[folder:Real Life]]
* Many people (mostly men) that can control their muscles will do this. Heck, ''anyone'' can do this if they're good at controlling their muscles and have the muscle strength to do so. If you actually want to know how to do so, check out [[http://www.livestrong.com/article/521108-how-to-do-pec-bounce/ these two]] [[http://www.livestrong.com/article/319367-how-to-flex-pecs/ articles.]]
** [[http://www.youtube.com/watch?v=2VsJXfAxeqo This]] includes many people that have a Website/YouTube account.
** [[http://yt2gif.com/view/413813 Heck]], [[http://gifsoup.com/view/2733651/pecs-bounce.html there]] [[http://gifsoup.com/view/3502683/hot-gymnast-anthony-pec-bounce.html are]] [[http://www.yt2gif.com/view/150781 also]] [[http://www.yt2gif.com/view/150801 animated]] [=GIFs=] [[http://www.yt2gif.com/view/209692 of]] [[http://yt2gif.com/view/373763 people]] [[http://yt2gif.com/view/413832 pec]] bouncing.
* Any pro-Bodybuilding contest will have this.
* Bigg Vinny Mack from TrailerChoir and ''Series/TheBiggestLoser'' does this [[http://www.youtube.com/watch?v=AeIweoj3_Vk in this video.]]
* [[http://gifsoup.com/view/4130067/mark-dalton-and-zeb-atlas-pec-bounce.html Mark Dalton and Zeb Atlas]] can do some excellent pec bouncing.
* [[http://www.youtube.com/watch?v=dqgU2wg7Io8 Here's a shirtless bartender]] for you.
* Robert Maschio who plays The Todd in ''Series/{{Scrubs}}'' does it in [[http://www.youtube.com/watch?v=rj1EDNVQsgY this video.]]