This summer, YMCA member Kelli McDonald will run 142 miles over a six-day period. For those counting—that’s almost one marathon per day. Kelli, a long-time athlete turned triathlete, was one of 16 runners chosen to be a part of MS Run the US, a relay across America that benefits the 2.3 million people that are affected by multiple sclerosis worldwide.

To prepare for this event, Kelli has been training nonstop at the C.W. Avery Family YMCA since January, sometimes twice per day. She’ll continue to train until July 7, the day she departs from Davenport, Iowa, beginning her 142-mile trek across the state of Illinois.

The seven months she spent training will finally pay off when she reaches her final destination in downtown Joliet on July 12. There, in her hometown, Kelli’s journey will come full-circle, when she crosses the finish line with her mother and biggest inspiration, Peggy, who has battled MS for 25 years.

“I just think about what my mother has to endure everyday. What I’m doing is nothing,” Kelli said. “She lives with pain everyday. She lives with numbness and fatigue—24/7. Every day is a challenge for her.”

In 2008, Kelli’s mother was diagnosed with MS onset scoliosis, which required major spinal surgery. Today, she lives with secondary-progressive MS, which means that the disease progresses more steadily (although not necessarily more quickly). The resilience that her mother has shown over the years has been a major influence on Kelli.

“She’s amazing,” Kelli said with a smile on her face. “Her spirit and her strength and her determination…MS isn’t going to stop her.”

Kelli, too, has a strong mentality. She has devoted the past several years, advocating for MS. In 2010, Kelli dedicated her entire triathlon season to her mother and those affected by the disease, raising money along the way.

“This isn’t a ‘me’ thing,” Kelli said. “I’m running for people. I’m running for a cause. The world becomes a whole lot smaller when you see how many people this affects.”

Over the next couple months, you might spot Kelli cross training at the Y, sporting her orange getup in support of MS. When she’s not training, Kelli and her husband, Paul, spend time with their very active children: Evan, Faith and Alex.

To learn more about Kelli and her amazing journey, visit her personal page.