Her freestyle stroke makes her look like the Katie Ledecky of 16-year-olds, metronomic in rhythm.

While Margaret Rivard’s peers on the Concord Sailfish Swim Team splash in the pool at the Concord YMCA, she swims steadily, back and forth down the lane over and over again.

To her, it probably feels like the equivalent of a Major League Baseball player playing tee ball. After swimming across the English Channel in early September, becoming the youngest to complete the Triple Crown of Open Water Swimming, this was peanuts.

Last summer, she swam 28.5 miles around the island of Manhattan, under 20 bridges and down three rivers. In 2021, she swam 20 miles from Santa Catalina Island to the mainland of California. In all, she completed three swims totaling nearly 70 miles and more than 30 hours of swimming in open water.

“It’s hard to explain,” Rivard said when asked why she loves swimming so much. “It’s just so much fun to me. The community is great. Really just the whole part of it. I love doing it.”

It began when Rivard was just six months old. She joined a swim team at 3 and swam her first open water event at 7. Her family lives on Lake Kolelemook in Springfield, so open water was never that far away.

Her older sister, Vera, also swam and completed the triple crown by the time she was 17. Margaret didn’t trail far behind.

“We used to call Margaret ‘Me Too Margaret,’” her mother Darcie said. “She wanted to do anything her sister did.”

Neither of Margaret’s parents are intense swimmers, but she can always count on them to be by her side kayaking while she swims these open water events.

During these long swims, there’s not much time to eat. Rivard said she’ll stop for about 30-second intervals for Gu, an energy gel that provides a much-needed boost. She can never stop for too long, though. Otherwise the currents will knock her off course.

But on Thursday and for the next several weeks, Rivard is back in the controlled confines of the Concord YMCA pool. No need for Gu or for worries about mysterious sea creatures swimming up beside her.

She won’t swim the same long distances in the pool that she does in open water, but it’s still an opportunity to stay conditioned.

And while completing the triple crown was a cool milestone, she’s nowhere near done with these open water challenges.

Next on the list, she said, is the Lake Monsters Triple Crown. She’s already completed one of the events at Lake Memphremagog in Vermont. The other two take place at Loch Ness and Lake Tahoe.

“I’m very impressed with her drive to do this. I just think it’s incredible,” said Liz MacBride, Rivard’s Concord swim coach. “She’s got this steel that just makes her want to do these different challenges. I’m very impressed with this girl.”