Among the many fitness options available to folks who are on their way down the aisle is ballet-based interval training—you’ve heard of this. Most options have the word bar or barre in the title.

At the Bar Method (there’s one in South Lake Union in Seattle and one in Redmond), they offer a special bridal package: $150 per month for six months of unlimited classes. It’s a great deal in terms of fees; for those of us who cannot provide proof of an upcoming 250-person celebration, the regular all-you-can-take 30-day period goes for $250.

What would it be like to throw yourself into muscle carving and body shaping for 180 days? Bar Method co-owner and instructor Bev Currier says it’s transformative. "We strongly encourage before and after pictures from the brides-to-be," she says.

Me, I can only tell you what it’s like to throw yourself into the Bar Method for an hour. I visited the SLU studio—an exceedingly tidy Tiffany-blue and modern white chandelier-lit space that feels more like a spa than a gym—to see what all the bride-to-be buzz is about. (Apparently, some gals are even making these training sessions into parties.)

Here’s what I learned:

-That window that faces Westlake Ave? It’s indeed a window into the workout room. You might drive past Whole Foods and then the studio while looking for a parking spot and think to yourself, ’There’s no way we’re working out in that room’ but, yeah, you are. Neighbors with dogs on leashes and kids in carts stroll by. Not oblivious. More like interested, and by turns, impressed, intimidated, or amused. Sure lots of gyms have giant street-facing windows, but here, there’s no spin bike to hide inside of.

-You should probably wear black yoga pants. I wasn’t the only person not wearing calf-length black stretchies and a solid-colored tank top, but I was definitely the only one in short stripped leggings and a day-glo pink screen-printed v-neck tee. I suppose it’s the ballet thing; a uniform feels right, and you will feel a little stupid for not anticipating that.

-Bar Method classes move along at a fast pace, and it begins immediately. One of your first clues is the music: Bruno Mars and electro-dance buzz. Forget what you know about a gentle warm-up and some easy stretching. With the Bar Method, stretching comes at intervals, and getting or staying warm, well, it isn’t a problem.

-You’re an individual here. Throughout the class, as Currier calls out quick clips of instructions, she slips personal posture notes to people around the room. She seems to know the names of all 30 or so women in the class, and maybe even their fitness goals, too. "Emily, bend your knees more." "When’s the wedding, Sarah?" That last isn’t, like, a random curiosity, it’s a clearly stated motivation tool.

-But you won’t be babied. This isn’t one of those feel-good mind/body things. No one will encourage you to work at your own pace or adjust the instruction if you’re new. This is a serious workout, for people who are serious about challenging—and perhaps changing—their bodies. Instructors are intent on you getting your money’s worth. In fact, they’ll make sure you get your money’s worth, even if, halfway through, you start thinking you’d happily pay double the class rate to quit right then and go get a cheeseburger around the corner.

-You will reflect on Natalie Portman in Black Swan. During the actual barre portion of the class, when at least there is something to hold on to, you will say to yourself, ‘No wonder she went nuts. This sh%# is crazy.’

-Your body will do some weird stuff. Like shake. Sort of violently. It’s supposed to. If it doesn’t, you’re not doing it right. "I love to see that shake," Currier says as you balance on the balls of our feet (or try to) with knees bent (hopefully at just the right precise angle). "It’s beautiful. That’s how I know you’re changing your body."

-You will have a lot of respect for the other people in the room. They will be 62 and 23 and 116 pounds and 180 pounds. They will seem like former dancers, they will seem like new moms. As their legs shake furiously and they blow out sharp, flexor-muscle breaths and Currier encourages them with a "This is how you taper your legs," you will want to tap into their determination and their success.

-Around this time you will stop looking at the clock and worrying about whether or not someone you know is going to happen by those big picture windows. And, as the class ends, you will put the mats and weights away, and you will find yourself wanting to do it again.