Despite the similarities in title with the popular 5K foot race distance, this is no simple weekender fun run.
"My one friend says it the best," Antonelli said. "She is running 4K for cancer, and when I say 4K, I mean four thousand."
Antonelli, who lives in Sykesville, is part of Team Baltimore, a relay team that will run from San Francisco to Baltimore, raising funds for the Ulman Cancer Fund for Young Adults. It's a summer-long commitment.
"They dip their feet in the water in San Francisco, and it ends at Federal Hill in Baltimore," said Jenifer's father, Jerry Antonelli. "They will dip their feet in the water there in Baltimore and then they run up to the top of the hill and that ends on Saturday, Aug. 5."
The 30 runners who make up Team Baltimore run in pairs, logging 2 to 3 miles at a time before hopping back in a support van for the trip, Jenifer said. They will each log 10 to 16 miles per day, a feat for which she has been training since December and all the more impressive because she was not much of an athlete until recently.
"I ran a few half marathons and one marathon, but nothing very intense. I was not a runner in high school or college," she said. "I wasn't looking for a race; I wasn't looking for a volunteer opportunity. It just kind of fell in my lap, and I didn't want to say no to it."
Now that she has had time to think about why she is running, Jenifer made a list of those in her life who have been affected by cancer.
"On top of that I have a lot of friends and family who are survivors and I admire all of them and I am running in honor of them," she said.
Jenifer's run was off to a good start, even before she arrived in San Francisco: Between home-cooked Italian buffet fundraising dinners and directing people to her fundraising website at ulman.z2systems.com/jen-antonelli, she has already exceeded her fundraising goal of $5,000. She hopes to raise more during her journey across the country.
"We have talked to people all over the place, telling her story," Jerry said. "We were in Baugher's Restaurant just the other day and talking to someone and they said: 'Give me the website. My wife died of cancer, and I will donate to the charity.'"
The proceeds from the 4K for Cancer events — there is also a bike ride — go toward the Ulman Cancer Fund's mission of supporting young adults diagnosed with cancer, according to fund spokeswoman Sasha Nader.
"One of the things we try to do is fill the void for young adult cancer patients, the 15-39 age group," Nader said. "There is a lot of focus on pediatrics, which is important, but when you are a teenager or in college, or a young professional who just started a family, those are the people that sometimes get lost."
The nonprofit funds navigators at Baltimore area hospitals who can help direct young people to resources, offer a Cancer to 5K training program — just 5 kilometers this time — that helps cancer survivors get active in recovery and, Nader said, helps young people preserve their fertility during treatment.
"They are still in those years and a lot of cancer treatments will affect your fertility. If you want to one day start a family and have kids, that's something you have to consider," she said. "We have a partnership with Shady Grove Fertility, and they will provide the first year of storage for free for our patients."
In 2016, 4K for Cancer events raised more than $840,000 for these programs, Nader said, and the 2017 events have already raised more than $720,000. Since 2013, she said, more than 1,000 people have participated in the cross-country fundraiser, by foot or pedal, and they have raised a total of more than $5 million.
"We are already accepting applications for 2018," Nader said. "If people are inspired by Jen and want to do something like that, they can go to our website and apply for next summer."