Eileen Young from Northport and her daughter Delilah, 1, work...

Eileen Young from Northport and her daughter Delilah, 1, work on ballet moves during a Bumps and Babywearing class in Commack, Saturday, Jan. 10, 2015. Credit: Randee Daddona

Baby weight has a new meaning.

For some moms, strapping their babies to their chests, or lifting them during exercise class, is a way to bond while also efficiently getting in a challenging workout. Whether it's Bumps and Babywearing Ballet, Mommy and Me Pilates or Mommy and Me Tribal Fusion Belly Dance, these classes across the Island are incorporating the wee ones into the exercise ritual.

WHAT Bumps and Babywearing Ballet

WHEN | WHERE 9:45 a.m. Saturdays at The Studio of Commack, 717 Larkfield Rd., Commack

INFO $18 per one-hour class; 631-858-1788; thestudioofcommack.com

As Lindsey Coffin, 34, of Port Jefferson Station executes a plié in her Saturday morning ballet class, her son, Oliver, 20 months old and strapped to her chest, simultaneously pats her face and head.

Across the studio, Eileen Young, a 35-year-old speech therapist from Northport, is concentrating on the instructor's command to "Bring your arms all the way up." Young's daughter, Delilah, 13 months, also strapped to her mother's chest, raises her own arms as well.

When the women form two lines to sashay across the studio, Karyn Provenzano, 30, a court reporter from Lynbrook, makes the movement while her son Henry, 3 months, sleeps obliviously in the baby carrier she's wearing.

This is the Ballet Mama class at The Studio of Commack, where moms from across Long Island come to take ballet class while wearing their babies on their bodies. Some of the tykes, like Coffin's son Oliver, weigh in the neighborhood of 20 pounds.

"He absolutely loves it," Coffin says of Oliver. She loves it, too. "It's always fun to get together with a bunch of moms and be active. I have three kids, so it's nice to get some alone time with him."

The ballet class is modified to accommodate the fact that moms are encumbered -- and some are expecting. "They couldn't do anything bending from the waist because they're either having a baby or wearing one," says Marissa Rignola, who runs the studio with business partner Jamie Chandler-Torns. No deep pliés, no high kicks, no extremes, she says. But, says class instructor Mariana DeMarco, 22, of Smithtown, "You do it for an hour and it becomes cardio."

Bumps and Babywearing Ballet is a niche class offered at The Studio, which opened in October. Rignola's friend Jessica McNeill, an administrator for the Long Island Babywearing group on Facebook, suggested The Studio develop a class geared to babywearing moms, who carry their babies on their fronts or backs as much as they can to foster bonding. McNeill attends with her 17-pound son Malcolm, 9 months, whom she puts on her back so he can look around. "He's added weight. It really works your muscles, core, arms and legs," she says.

WHAT Mommy and Me Pilates

WHEN | WHERE Noon Mondays, Wednesdays and Fridays, call for Saturday hours, at Find the Midline Pilates, 77 Jericho Tpke., Mineola

INFO $20 per 55-minute class; 516-423-9431; findthemidline.com

Terri McAuliffe, 29, of Floral Park, lies down on a Pilates Reformer using a Jumpboard and sets her baby, Brayden, 5 months old, on her stomach. She repeatedly pushes off the base in a quest to strengthen her legs, with a happy Brayden along for the ride.

McAuliffe is taking a baby-and-mom Pilates class at Find the Midline Pilates Studio in Mineola. "It works your core, that's the focus of it," studio owner Bianca Velez says. "The idea is to become stronger at everything you do. Your baby is your prop."

Velez created the Mommy and Me Pilates class after her daughter, Francesca, now 3, was born. "When you're not working, you want to be with your baby," she says. "How do you get these workouts in often enough? Working out with your baby provides another way of getting it all in for moms."

Class accommodates babies; for instance, if a mom needs to nurse, she can take care of that and then return to class, Velez says. Classes are small due to limited equipment, so moms must sign up in advance.

During class, each baby helps Mom exercise -- strengthening her arms, for example, as she holds him and flies him in a figure eight.

"Fly the babies around like little Supermen," Velez instructs. The babies look at each other as they fly. One lets out a high-pitched, gleeful sound Velez jokingly calls a pterodactyl scream. Anthony, 10 months, is laughing as mom Angela Raimo, 31, of Glen Cove sweeps her 16-pound baby through the air while working up a sweat.

WHAT Mommy and Me Tribal Fusion Belly Dance

WHEN | WHERE 9:30 Mondays and Fridays at Tribal Dance Long Island, 26-28 Vernon Valley Rd., East Northport

INFO $15 per one-hour class; 631-754-0385, caravanconnectionnewyork.com

The coins in Cienna Rizza's hip belt clack together as she leads her Mommy and Me Tribal Fusion Belly Dance class in swaying their hips. She tells the moms to move their hips in a figure 8.

"Gloryvette! You're so sexy!" Rizza yells in encouragement as Keltic music plays and Gloryvette Rodriguez, 35, of East Northport, swivels her hips with her son, Jace, 9 months, in a baby carrier on her chest.

Ariane Amsz-Fields, 43, a physical therapist from Northport, sways next to Rodriguez, with her son, Luka, 21 pounds, on her chest. "He's been with me the whole exercise and female empowerment journey," Amsz-Fields says. She says it's important for moms to hang onto their femininity and sensuality. "Just because you're a mom doesn't mean you lose that," she says.

Dawn Tlustachowski, 38, of Farmingville, brings her 2-year-old, Jonathan, to class and he stands and sways in front of her. Kids up to 4 can attend with mom, Rizza says.

Tribal belly dance is meant to be done in a tribe, says Rizza. "It's meant to be done with your sister, grandma, mother, friends. You don't have to be 21 and 110 pounds. I'm not a mom myself, but I know what it's like to want to feel beautiful and sensual and reconnect with the woman inside."