Bartell, a 36-year-old stay-at-home mother living in St. Louis Heights, liked Stroller Strides so much, she continued with the program when she got pregnant with her son, Nicholas, now 5 months old.

"Sometimes it's isolating when you have kids, because no one understands what you are going through," Bartell said. "Someone (participating in Stroller Strides) is always going through what you are going through. It's a lot more than fitness."

Stroller Strides includes power walking while pushing strollers and interval training using exercise bands.

"After having a baby, it's really hard to exercise," said Mobley, co-owner of Stroller Strides on O'ahu. "We really want to have a total-body workout, including cardio and muscle-toning.

"It's a good workout; you're going to come home and feel sore the next day."

Mobley, 34, brings daughter Josie, 2 1/2, and son, Duke, 5 months, as she leads the group of mothers through various exercises, including runs around the area, jumping jacks, lunges, and an ab workout.

Bartell said she could feel the difference in her body after joining Stroller Strides, especially while she was pregnant with Nicholas.

She said she had gestational diabetes with her daughter, Grace, now about 2 1/2, but not with Nicholas, "and that's a testament to Stroller Strides," she said.

When she first started out with the program, Grace "had definite attachment issues and I couldn't leave her with anyone. So this was perfect for us."

Now, she said, Grace will ask, " 'Is it Stroller Strides today?' And she's cried when there's no class," Bartell said.

Stroller Strides isn't only for mothers hoping stay fit while pregnant or lose post-pregnancy weight.

Megan Perry, 28, started about six months ago, after a friend gave her five free passes. She had just taken in foster daughter Zoe, and said she attended Stroller Strides because she "wanted to do things with moms."

With the added incentive of a workout, Perry used the passes, then continued attending.

"Since I got her, I wasn't able to exercise as much," Perry said of 9ý-month-old Zoe. "The instructor is like a personal trainer. This is better than a gym, and the baby gets to come, too."

The mothers are led in song by instructors who try to match each song with an exercise — "You put your right foot in, you put your right foot out ... ," which was sporadically interrupted with the sound of crying babies.

As mothers rushed between executing their exercises and tending to their children, it kept the children involved and the mothers breathing hard.

"It's pretty equivalent to what you would do if you went to a basic aerobic class," Mobley said. "Some gyms provide child care, but not until the child is six months old. And if your child starts screaming, they come and get you. Here, we tell you to take your time."

She said one of the main benefits of Stroller Strides is the socializing.

"Out of this, moms will end up going to do runs and things together," Mobley said. "If you like to exercise, it's another way to make friends who have the same interests."

It also teaches children to adopt a healthier lifestyle at an earlier age.

"The big thing is it models good behavior, as exercise is part of your life," Mobley said. "I hope she sees exercise should be part of your lifestyle. See that Mommy doesn't sit around and watch TV all day."