Lily Wilson's head quickly sank underwater. Instead of plummeting to the bottom of the pool or choking on a mouthful of water, the 11-month-old in a ruffled top and swim diaper held her breath and rotated onto her back.

Lily Wilson’s head quickly sank underwater.

Instead of plummeting to the bottom of the pool or choking on a mouthful of water, the 11-month-old in a ruffled top and swim diaper held her breath and rotated onto her back.

Although she cried, the baby stabilized herself in a float while waiting for someone to grab her.

After a few moments, instructor Mollie Zook put her arms around Lily’s chest and pulled her close, whispering “Good job” and rubbing the baby’s back.

Lily had shown Zook that she had mastered the key water-survival skills taught in Infant Swimming Resource to children as young as 6 months.

“At her second lesson, all she wanted to do was suck her toes, and now she can float,” said mom Alyssa Wilson, who watched recently from the side of the pool at the Westerville Community Center. “ My kids are on the swim team and with her toddling around this summer, we thought we needed to protect her.”

Wilson enrolled her youngest of five in the program after viewing an online video (which has more than 2?million YouTube views) of a baby using the skills.

Though considered controversial by some people and not necessarily viewed as inexpensive — Zook charges $75 a week — the classes are nonetheless gaining popularity in central Ohio.

In the 16 months she has been teaching, Zook, 33, of Worthington, has seen her list of students increase from just a few to 30. She is the only Infant Swimming Resource-certified instructor in Columbus, according to the program’s website.

The program, founded 40 years ago in Florida, has seven other independent instructors in Ohio, the site shows. Other infant self-rescue programs, such as Infant Aquatics in Cleveland, have instructors elsewhere in Ohio but not Columbus.

Which is why Zook, a mother of two and an avid swimmer, became an instructor here.

Infant Swimming Resource classes adhere to a philosophy different from parent-child lessons for babies that revolve around playtime and songs.

“Most of the time, the kids know this is time for work,” said Zook, who rents pool space at several central Ohio locations. “Parents can do all the fun stuff.”

Drowning is the leading cause of “injury death” nationwide for children 1 to 4, according to the Centers for Disease Control and Prevention. About 1,000 children younger than 20 drown each year in the United States.

In Franklin County, 14 children drowned from 2004 to 2009, according to Columbus Public Health’s Office of Vital Statistics.

“If you lose track of your child for a minute, it’s dangerous,” said North Side resident Abbey Ward, who last month enrolled sons Micah, 8 months, and Asher, 2, in Zook’s lessons.

The one-on-one sessions last only 10 minutes because young children have short attention spans and fatigue easily, Zook said. She meets with them on weekdays for three to eight weeks.

Those 18 months to 6 years old also learn to swim to the pool’s edge — which takes longer.

After several weeks, Zook tests whether babies can complete the skills while clothed.

“You don’t really think a baby can do what they can do,” Zook said. “It still amazes me. I don’t think we give them enough credit.”

During the first few lessons, Zook allows the baby to acclimate to the water and holds onto him while he floats. Then, she slowly loosens her touch until the baby can float for a short time — then longer — without her help.

She doesn’t move to the next step until the baby masters a skill.

Watching Zook let go of her baby in the water, Ward said, can be “freaky.”

Noting how opinions of the lessons vary, Wilson heard someone once equate the classes to “child abuse,” and another woman warned of water intoxication.

“When I see that in three weeks she has learned to save her life — that’s not child abuse,” Wilson said of Lily.

The American Academy of Pediatrics has loosened its stance on swimming lessons for young children since 2010. It advocates water-safety lessons for children as young as 1 when a child is developmentally ready.

For babies younger than 1, too little research has been done on water-survival lessons, said Dr. William Cotton, medical director of the Nationwide Children’s Hospital primary-care network.

“There haven’t been any good studies that show these work,” Cotton said. “They may work, but there are not any strong studies proving it.”

Plus, he said, the lessons won’t “drown-proof” a child. Parents still need to be vigilant in supervising children and installing proper barriers — fences, rigid covers and alarms — around pools.

“It doesn’t take the place of those,” Cotton said.

Parents use the class, Zook said, as an additional tool — on top of barriers.

Infant Swimming Resource has more than 800 documented cases of children saving themselves, she said, and at least one of her 80 former students has.

Aquatic Adventures in Hilliard hosts infant swim classes “predominantly geared toward structured playtime,” said Molly Fenby, director of operations.

She recently looked into adding Infant Swimming Resource to the facility, but the cost to certify instructors — about $15,000 each — and lack of demand in central Ohio deterred her. The program is well-known in states where water is more prevalent.

“I’ve watched the curriculum, and it’s fascinating,” Fenby said. “It teaches good core.”

She worries, though, that classes don’t teach skills for lifelong swimming.

Zook recommends that students return once a year for a week to learn new skills. Parents should also have water playtime, either in a class or independently, with children.

“Then they know water is work but it can be fun,” Zook said.

Although most children cry during lessons, Zook said, the tears usually result because she is in the water with them — rather than Mom or Dad.

Watching her child cry or go underwater can be difficult, Ward said, but she focuses on the payoff.

“You have to look at the bigger picture: They are learning to save their lives.”