The episode starts with Future Ted telling his kids that people used to go to “these silly things called gyms”, then it flashes back to Ted in 2007 not feeling like he’s in good shape. He convinces his friends to all join a gym with him and the b-plot to this episode is everybody at the gym.
Marshall hires a personal trainer, who turns out to be a pretty woman. But the pretty, petite woman screams at him and makes him cry “using only her words” and makes him do hundreds of pushups and situps until he’s so sore he can’t move.
Lily hires a personal trainer out of revenge, and he’s an older, fit guy who is going to “stretch her out”. Turns out he wasn’t affiliated with the gym and she doesn’t want to talk about it.
Robin loves working out because she doesn’t have to put on makeup or try to impress people, but Lily and Ted and Barney are all super mean about it.
Ted goes to the gym, but never exercises. He brings the wrong shorts, forgets to charge his ipod, or gets a massage. Eventually, Marshall transfers his training services to Ted and Ted has to deal with the mean pretty trainer screaming at him.
That brings us to Barney. Barney goes to the gym, but doesn’t work out there. He hits on overweight, out-of-shape women in the hopes that when they “get hot” they’ll come back to him because they trust him. Additionally, Barney recognizes the older woman who works at the smoothie bar in the gym. Her name is Rhonda, and she’s the woman who took his virginity.
This story was actually first introduced back in Episode 2.12 - First Time in New York. In that episode, he says,
“I was 23, and it was with my mom's 45-year-old divorced friend, Rhonda. She called me ‘Barry’ the whole time, and for two weeks, my comforter smelled like menthol cigarettes.”
So now the writers are giving us the details on that particular story. We also saw the chapter of Barney’s story that led to him losing his virginity back in Episode 1.16 - Game Night, when he broke up with Shannon after graduating college. This episode also gives the audience more information about James’ “college hetero phase” which is mentioned in Episode 2.10 - Single Stamina.
This episode is a little like a novella in between the full-length novels of the main series. It doesn’t do anything to push Ted’s story forward, in fact Ted is barely in this episode. Thinking of the framing of the show, it doesn’t even make a ton of sense that Ted would tell this story to his kids. He’d have to know so much about Barney’s upbringing, James’s process of coming to terms with his sexuality, and a whole lot of other stuff Barney is clearly embarrassed by.
I see these pop up in YA SFF especially, but they could really work with most series. A few notable examples I can think of include:
Sarah J Maas has five companion novels for her THRONE OF GLASS series that chronicle the main character’s travels prior to the series starting and then during the time off-screen between book one and book two, making the climax of book four much more powerful
Maas also has a companion novella for her COURT OF THORNS AND ROSES series, but this one is an abbreviated sequel/finale to the series
Tahereh Mafi has companion novellas in between the original trilogy of her SHATTER ME series, each one giving voice to a different love interest for the main character
Stephenie Meyer wrote one from the perspective of a character so small in her Twilight series that the character had only one line in the original book and wasn’t even named until the novella came out
Dan Wells wrote NEXT OF KIN to introduce a new cycle of books from an already-established narrator whose story had felt finished
Brandon Sanderson uses novellas between his SKYWARD novels
The key to successfully launching a story like this is to choose the right character and the right moment to highlight. In the case of Maas and Wells, they use their main character, or their POV character for these novellas, but they’re telling a story that isn’t directly related to the main plot of the big books. It ties in, since it’s part of what makes this character, but it isn’t totally necessary to the big plot. You can read the big story without reading the little ones and you’ll be just fine. The little stories, however, make the bigger story a little richer, a little more compelling.
Mafi and Meyer, however, chose a different character to narrate their novellas. In both cases, the main series is in first person POV. In Mafi’s stories, she uses the two warring love interests to narrate the novellas. At the end of the second novella, the audience is completely hooked on one love interest over the other; anyone who skipped the novellas went into the last book in the series still torn about who the main character would end up with. These were both major characters - arguably #2 and #3 in terms of importance to the overall story - who had very different voices and very different perspectives on what was happening to the main character.
Contrastingly, Meyer used a teeny-tiny character to narrate a story that shed some light on how the villain worked. She didn’t use a villain for the POV, but a victim who could then make the audience better understand the horror of the villain’s actions.
Choosing the right character to narrate this smaller story is critical to its success. HIMYM is locked into the format of Future Ted telling a story to his kids, but I would argue that Ted is completely ancillary to this story. This is Barney’s story. Barney is the one with the flashbacks, Barney is the one with the arc. Ted’s presence is awkward at best (somehow Mr. High Strung is able to play it totally cool while talking to Heidi Klum?) and obviously only because it’s a sitcom.
Up to this point, Barney has been really mysterious. His flashbacks and personal anecdotes have done little to illuminate his life to us. The story of how he became Barney was interesting, and the gag with Bob Barker as his dad was funny (but obviously a cross-promotional opportunity more than anything), but this is a pivotal moment in Barney’s life. It affects who he is right now, it has some bearing on the current story Ted is telling. Setting a novella in-world but with a totally unrelated event isn’t all that interesting; this one is interesting because we see why and how it ties in to the main story.