MONMOUTH — Not much seems to rattle North Yarmouth Academy boys’ soccer coach Martyn Keen.

While spectators at the Class C South semifinal Saturday at Monmouth Academy held their breath every time a scramble ensued in front, Keen didn’t move – not even to remove his hands from his pockets.

But Keen wasn’t always so laid-back.

“I used to be a much more vocal coach,” Keen said. “I was an equal-opportunity yeller. I’d yell at anybody: referees, coaches, players.”

That changed when Keen almost died. Twice.

The 54-year-old’s most recent run-in with death came when he was diagnosed with esophageal cancer in April. A coach for NYA since 2010, Keen relinquished his duties this season to Stuart Thorley, who had a conflict and couldn’t make Saturday’s playoff game. After undergoing months of grueling treatment, Keen is cancer free. And for the first time since his diagnosis, he was back on the sidelines coaching.

“Martyn is literally one of the strongest people I’ve ever met,” said Wallace Jackson, a defender for NYA. “He said his chances were slim but in his mind, they were a lot higher. That positive energy – it pays off.”

After suffering a 2-1 loss Saturday to the top-seeded Mustangs, Wallace and his teammates sat on their bench in the rain, clad in T-shirts adorned with the words, “Keen Strong.”

Keen’s smile seemed to be infectious as they joked around like their season hadn’t just ended.

“All of us have a lot of love for Martyn,” said one of NYA’s senior captains, Xander Bartone. “Hearing that (he had cancer) was really eye-opening. It reminds you that high school soccer is only so important.”

Keen – also the director of coaching and player development at Seacoast United Soccer Club – broke the news to his players last spring in between cracking jokes.

“He was talking about how he couldn’t eat the food he wanted to eat,” Jackson said, “like that was the one downside of cancer.”

Since then Keen has gone through chemotherapy, radiation and an esophagectomy – a surgery that involves removing the esophagus and replacing it with part of the stomach or large intestine.

“So your stomach is,” Keen said with a smile while thinking of the appropriate word, “misplaced. I have to learn how to eat again.”

Keen can only eat small portions at a time and struggles to keep food down. He weighs just 130 pounds – 35 less than before his diagnosis.

“Chemo and radiation doesn’t really stir your appetite,” Keen said before shifting to a positive note:

“I kept my hair, though!”

While Keen’s recovery is ongoing, he has overcome worse odds. In 2008, he was presumed dead at the scene of a boating accident at sea after a piece of hydraulic machinery malfunctioned while he was working underneath it. It crushed him, breaking all of his ribs and ligaments, four vertebrae and his sternum.

He wasn’t expected to live, but – two years later – had made a full recovery. He said the accident changed him.

“I got wise,” he said. “I want to make sure I have a legacy when I head out the door. There is a one-in-one chance I’m going to die.”

His players are not so sure.

“You’re two-for-two on not dying,” Jackson pointed out.

The community has been there to help Keen through his cancer. NYA and Seacoast United created a Go Fund Me page, where they raised enough money to purchase a mechanical bed – a necessity for him after the surgery, which has left him unable to lay flat because he no longer has the muscle to stop reflux.

As grateful as Keen is for the support, his players are thankful for his. He made it to 12 of their 15 games this season – and he plans to be back on the sidelines as their coach next fall.

“Having him around was always an inspiration,” Bartone said. “I would always look up at the sidelines at halftime, and I would see him there watching right after chemotherapy – it means a lot.”