As Kelli Cutinella ran in last Sunday's Tunnel to Towers Run, she found herself alongside Karen Hill, a woman with a very special heart -- one that had been donated by Cutinella's late son, Thomas.

It had been a year since she and her husband, Frank, had lost their son, and now Kelli and Hill were running in Tom's favorite race.

"It was a new first for us because Thomas wasn't there," Kelli Cutinella said yesterday, before choking up and adding, "But he was there, in Karen."

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Thomas Cutinella, 16, of Shoreham-Wading River High School, died on Oct. 1, 2014, after a collision with another player during a football game against John Glenn High School.

Months earlier, while taking his driver's permit test, Thomas instructed his parents that he wanted to be an organ donor.

On Oct. 3, Hill, then a 21-year-old Fordham University student, received his heart.

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"It was a very moving experience for me," said Hill, who required a heart transplant after being diagnosed with a serious ailment at age 11. "It was such a tragedy for that family, but they did such a selfless thing for me and my family. I'm so grateful for what the Cutinellas did. A year ago, I couldn't climb a flight of stairs. Now, I'm running again."

Hill's mother, Gail Tyus-Hill of Washington, D.C., said that without receiving Thomas' heart last year, her daughter "might not have survived the weekend."

Kelli Cutinella, who had been in communication with all of her son's organ recipients, said she and Hill, who now lives in Manhattan, made plans to meet at the New York City Tunnel to Towers event, though they hadn't talked about running together.

"It just happened, and we stayed right by each other," Kelli said. "It was amazing to me. This was Thomas' favorite run and I knew he was with me."

Life has changed irrevocably for the Cutinellas since Thomas' death, which his father said was caused by "a helmet-to-helmet hit on a play he never saw coming."

"We don't blame anyone," Frank Cutinella said. "We'll never blame the coaches; we'll never blame the player; we'll never blame the refs. But I do think we need to make changes to the sport. That's a reality."

There are many haunting reminders for Frank and Kelli. "No holidays together. No birthdays. Seeing him pass his road test or go to his prom. It's those things," a tearful Kelli said. "And then seeing his peers go through it. I'm excited and happy for them but it just reminds me that Tom's not here for those things."

Those things include the simple act of dining out, when Frank and Kelli, who have two other sons and a daughter, can no longer ask for a table for six. "It's horrible. It's a reality. But that's just a small part of it. We did everything as a family of six," Frank said. "That's just one of the many, many challenges we have to move forward with our lives."

An overriding element to the past year has been Kevin Cutinella returning to the sport that took his brother's life while he watched on the sidelines as a substitute on last year's Shoreham-Wading River team. A 15-year-old junior, he is a starting linebacker/running back this season.

"I probably would have preferred that Kevin didn't play," Frank Cutinella said. "But he's a young man and I support his decision. He's played since he was 6. Tom started when he was 7. I would do anything to have my son back, so of course I would never have introduced Thomas to the sport. But, like myself when I was a young boy and a teenager, he fell in love with football. I can't take that away from him."

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Frank Cutinella misses the days when he spent hours on the couch in the den, watching college and pro football games on TV with Thomas. In fact, he has lost his passion for football.

"I don't watch college games anymore. I'll sit with the family if they are watching an NFL game, but football will never be the same for me," he said. "Football has no meaning for me now, other than watching Kevin play. It's hard for me to watch."