But in one crucial way, she stands apart, though not alone. She is battling an extremely rare cancer. And it is not slowing her down.
On a beautiful fall morning in New York City, she and her husband, Justin, walked into Memorial Sloan Kettering Cancer Center for an appointment. Grunewald is enrolled in a clinical trial overseen by Dr. Alan Ho, an oncologist at the center. After the appointment, Grunewald laced up her running shoes for a jog through Central Park. Matching her husband stride-for-stride, it was here, on the running path, where she was truly in her element. For Grunewald, running is as much a part of her treatment as any medicine.
In 2009, at 22 years old, Grunewald was at the top of her game. As a walk-on to the University of Minnesota Golden Gophers track team, she had worked her way to a starting spot and was entering her senior season. Then, one day, she felt something strange under her ear.
"It was tiny," Grunewald remembered. "But if I pressed on it, I had a little bit of a tingling sensation. It just wasn't fully normal."
The team athletic trainers weren't sure either, recommending that she see an ear, nose and throat doctor, where Grunewald had a fine needle biopsy. While waiting for the results, she traveled with her team to Arizona State University, ready to open her season with the 1500 meters, her premier event. In the lobby of the hotel, she got the call.
"I remember very few things about the phone call," Grunewald said, "other than just knowing that it was cancer and that I would have surgery and possibly radiation and that it was basically going to end my season."
On the phone, the doctor told Grunewald the name of her cancer: adenoid cystic carcinoma. She'd never heard of it, so she googled it. It wasn't very promising.
"I saw that there aren't any treatments for it," she said. "I just saw that it was a rare cancer."
Grunewald found one piece of information she took comfort in: At least in the near term, the survival rate was relatively high. "The five years, I think it was a 95% survival rate," she said. "I just wanted to focus on those five years. That was the way for me to sort of carry on with my life ... and then ultimately back into running, which is what I really wanted to be doing."
Adenoid cystic carcinoma is most commonly found in the salivary glands of the head and neck. It is also very rare.
"You can estimate that the number of new cases per year in the US is about 1,200 or so per year," said Ho, who specializes in rare cancers at Memorial Sloan Kettering. "So it represents less than 5% of all malignancies that occur in the head and neck alone."
For someone like Grunewald, who had no family history of cancer, it was shocking to be staring down not only a cancer diagnosis but a rare one.
"There are a number of challenges with rare cancers," Ho said. "Any time you get a cancer diagnosis, it's a life-altering type of thing. But then to also be told by your oncologists or physicians that they've never seen these cancers before, they're not sure what the treatments are, is very emotionally hard."
Grunewald had surgery for the first time in her life, in which doctors removed the tumor in her parotid gland. She started radiation treatments a month later while trying to stay connected to running in any small way she could.
"Some days, I ran to my radiation treatment, and I would run home," she said. "It was like 10 minutes there, 10 minutes back. It's not a lot, that's not real training, but it was a way for me to stay connected to the idea of running. But I was really patient with myself. I just knew if I let my body recover and heal that I would be able to run again."
After undergoing radiation treatments all summer, Grunewald eventually returned to running and began posting personal bests, running faster than she ever had before. She became an All-American, finished her degree, made the US championships and signed a contract to be a professional runner with Brooks Running Co.
Then, in 2010, a year after the initial diagnosis, Grunewald was diagnosed with thyroid cancer. Doctors were unsure whether it was related to the original disease or just a bizarre one-off. She had surgery again, coupled with a radioactive iodine treatment, and continued running.
But in the back of her mind was one of the things she'd learned about her first cancer -- the high likelihood of recurrence. Still, seven years would pass with no sign until one morning in August 2016 when her husband gave her a hug. Grunewald's side felt hard.
She had been feeling fine. In fact, she'd made the 1500 finals of the Olympic trials just a few weeks before. But scans revealed a large tumor on her liver. Because adenoid cystic carcinoma most commonly recurs in the lungs, previous scans had focused there and not on her liver. Grunewald needed surgery again. Doctors removed a 4-pound tumor, roughly the size of a softball, leaving a 12-inch scar across her abdomen.
Grunewald's cancer had returned. After she had the large tumor removed, follow-up scans of her liver revealed a dozen smaller tumors in its place.
She sought out alternative treatments when traditional therapies like chemotherapy failed to effectively manage her cancer. That's when she found Ho and his immunotherapy work at Memorial Sloan Kettering.
"Traditionally, we've been using chemotherapy for this disease, although there are a number of trials showing that chemotherapy doesn't work as well as we'd like," Ho said. "So a number of the different directions we've gone [includes] trying to use drugs to target some of the genetic lesions of the tumor. One of the things we're currently investigating is whether these new immunotherapies, these drugs that activate the immune system, can have any role in the treatment of adenoid cystic carcinoma patients."
Immunotherapy harnesses parts of the body's own immune system to fight the cancer. Typically, cancer cells evade the immune system. Specific molecules form a barrier around the cancer cells, sending out a signal that convinces the T-cells of the immune systems that there's nothing abnormal. By blocking these molecules, the cancerous cells are exposed, and the T-cells can do their job. Grunewald is willing to try it, because at the age of 31, she is battling cancer for the fourth time in less than a decade.
"Anyone who meets [Grunewald] for the first time can see right away, she's very focused and determined," Ho said. "She has a great optimism and positivity about her that really helps her approach to the disease."
"I try not to spend too much time wondering 'why me,' " Grunewald said. "I've learned over the last eight to 10 years of dealing with this that there are a lot of rare diseases. A rare disease in itself isn't that rare. It's rare in the sense you get a specific one."
Grunewald now receives her immunotherapy transfusions at the Mayo Clinic in Rochester, Minnesota, closer to home, while having Ho remotely manage her care. She continues to run and train as much as she can. If and when she beats this again, she wants to be ready to hit the track competitively. In the meantime, she's also lending her voice as a young cancer patient dealing with a rare disease.
"It is tough to talk about, but I think I have been very open with my situation from the beginning," Grunewald said. "I think being an athlete, and being a runner has definitely effected how I approached surviving cancer. It's a sense of, I grind through my training and my runs, and sometimes it's really hard. But there's always a light at the end of the tunnel, and sometimes it takes a while to get there.
"I take some of that attitude into surviving my cancer, and there are days that require so much endurance and patience and persistence that you have as a runner. There's some tough races that I've had to bounce back from, and tough workouts, and that's the same thing with my treatments. And setbacks in my disease, I still feel like there's a way for me to get through it."