I WAS JUST SITTING THERE on my mat, stretching out the hamstrings, waiting for Ladies Strength Training to start, when the Ghost of Workouts Past bustled in.

“Hey, y’all, I’m Denise! I’ll be filling in for JoJo! She’s doing the Death Valley triathlon!”

Denise had it all: Richard Simmons—level peppiness, blinding white tennies, a leotard cut up to her waist, leg warmers, and a headband. She could not have been more perfect if she’d been Jane Fonda ordering us onto all fours to “go for the burn” with some fire hydrants.

“All right, ladies! Let’s get started!” Did I say that Denise couldn’t have been more perfect? She got more perfect: She put on the ur-aerobics song “Super Freak,” and as Rick James yowled, Denise ordered, “Give me a grapevine! Grapevine with a ham! Hustle up! And back! Whew! Come on, now!”

Denise’s quaint, old-school ways caused me to think back upon my years on the bench—the step aerobics bench. I started going to aerobics classes roughly two decades ago, when my metabolism and discipline dropped to the point that the only way I’d exercise for more than two minutes straight was if I had a roomful of strangers watching me. The discipline part continued to drop, so that now I have to visualize all those strangers armed with bayonets pointing at my capacious can. (That and the crystal meth do the trick.)

A whole anthropological study could be built around women’s exercise classes. For many of us, they are our quilting bees, our menstrual huts, our human genome sequencing labs. Okay, not the last, but there have definitely been times when just one hour a day of listening to music that was not Raffi and being around humans who wouldn’t put the cheese grater in the toilet the instant I turned my back saved my sanity.

“Y’all are quiet today! Must be Monday! Too many margaritas this weekend! Whew! Come on, smile, y’all!”

I smiled, for it had been many moons since a workout instructor had asked me to show teeth. The rise of kickboxing had pretty much ended the Happy Face/Barbie Doll years. Something about visualizing crushing your opponent’s windpipe with your foot was not compatible with such chipperness. Strippercize, of course, was a different story, since a lascivious grin, along with butt slaps and fingers in the mouth, was mandatory while working the pole.

“Let’s work those lats and delts! Strapless season is coming up! Let’s make our workout goal to look hot in a backless!” My class, which has a great group of new moms, a selection of spry seniors, a couple of young women training to pass the fireman’s exam, and several Iranian students in head scarves, seemed puzzled. They had goals of an entirely different sort, like getting on and off the toilet without assistance and carrying people out of burning buildings.

Or, possibly, they just missed our regular instructor, Mistress JoJo, a Flabbo Nazi of the first order. JoJo should be working in the fashion industry—she hates women’s bodies that much. She yells at us about our saggy butts and Hanging Gardens upper arms. Her music is a motivational mix of death metal and rap played at bowel-loosening volume. A particular favorite of JoJo’s, by the rap artist Ludacris, advises “bitches” to “move” and “get out the way.” If anyone talks, JoJo punishes us with extra reps. The seniors wear earplugs and looks of terror and wonder whatever happened to that nice instructor who played “Chattanooga Choo Choo.” But we all keep coming back, since our butts are getting perkier.

Different cultures, different workouts. I once visited a friend living at Zuni Pueblo. She took me to her exercise class, which was designed to help Zunis deal with skyrocketing rates of diabetes. The scarily buff instructor, who’d ridden her Harley in from Albuquerque, launched into a high-stepping, high-intensity routine that called to mind a Kilgore Rangerette’s being electrocuted. The lovely, round ladies of the Pweb responded with a gentle variation on the Corn Dance, waving their arms as languidly as algae in a slow ocean current. After a few minutes of this exertion, they took a break, split a Bit-O-Honey twelve ways, and spent the rest of the class gossiping.

As with everything else in life, the great divide in exercise comes between jock and rock. Are you “In it to win it”? Or are you “Only here for the beer”? Do you know what the trapezius and erectus femoris are, or are you not interested in the sex lives of circus performers?

Denise’s blast from the past made me wonder what the future of aerobics might hold. So, in the time-honored Texas Monthly tradition of going the extra mile, of scouring the nation to help its readers, I threw myself on the pyre of consumer research: I typed “exercise” and “classes” into Google, then tirelessly clicked on the first three links that came up.

Whoa, ladies! There’s a world of ways out there to keep your butt from sliding down your backside. Just reading the names made me tired: Abs’solutely Hysterical (“Laugh your way to flatter abs with this thirty minute abdominal blaster taught by a comedian”), B.L.T. (Butt, Legs & Thighs), Beach Body Bootcamp, Bikini Body, Buddha Belly, Cardio Striptease, Circus Sports, Gospel Aerobics, Heavy Metal Survivor, Hip-Hop Cowgirl, Midnight Yoga, Military Bootcamp, Steel Factory, Tread ’n’ Shed Extreme.

I was wondering whether I should contact Amnesty International for a full investigation when I spotted a class that sounded right up my alley: Naptime. “A guided meditation to escape from daily life—it’s the ultimate in relaxation and stress reduction. Feel free to bring a blanket and, of course, we’ll wake you up before it’s time to leave.” Naptime! Sign me up!

Just beneath my new favorite class I found Street Stairs, “an hour-long workout incorporating stair climbing, parking lot drills, and sports conditioning.”

Stairs and parking lots? I suddenly saw the future of ladies aerobics, and it was going to take place right in my house. Here are the classes I’ll be offering: Mo’ Mo’ Moppin’! Step ’n’ Dust! Sanitize! Cardio Vacuum! Laundracize! Shape ’n’ Shine! Tone ’n’ Clean That Funky Mess Outta My Refrigerator!

Who knows? If they’re really good, I might even allow my students to get down on all fours and go for the burn with some fire hydrants.