THORNTON, Colo. — The year he turned 40, David Knapp ran 40 marathons.

Just to prove he could.

“That was a selfish thing, just for me ... just to prove I was fit,” the 1982 Knoch graduate said.

Now employed as a leadership and organizational consultant in Denver, Colo., Knapp turns 50 later this year — and is in the process of running 50 marathons in 2014.

Only now he's running for a purpose.

Knapp lost his mother, Audrey Knapp, to Alzheimer's in 2001. He decided to run these 50 marathons — in 23 states, Washington D.C. and Canada — as a fundraiser for the Colorado Chapter of the Alzheimer's Association.

His goal is to raise $50,000 to fight the disease.

“I wanted to make my marathon quest more meaningful this time,” Knapp said. “I got on the (Alzheimer's Association) board and it's been a nice partnership.

“We've raised $7,000 so far, but this thing is starting to take off. I'm going on TV in Denver and I've got an interview scheduled with WPXI in Pittsburgh when I come in for that marathon.”

The Pittsburgh Marathon — his 19th this year — is May 4. Knapp is running in the Country Music Marathon in Nashville, Tenn., this weekend. He will run the Fargo Marathon in North Dakota six days after the Pittsburgh event.

He is not running a marathon only seven weekends from Jan. 11 through Dec. 7.

“A few weekends, I run one Saturday and Sunday,” Knapp said. “My approach is like an ultra-runner would do. I can't push myself as hard as I could during a race.

“I have to check my ego at the starting line, watch runners pass me who I know I could beat. I'm capable of running a marathon in three hours and 45 minutes, but I settle for times of 4:15 or 4:30 to preserve my body.”

Knapp said he's dealing with a sore calf muscle now — but that's nothing compared to what he dealt with during his first two marathons of the year.

While running the Mississippi Blues Marathon, he slipped on some bad pavement and suffered bruised ribs.

“I got a good case of road rash, too, but those ribs were the big thing,” Knapp said. “I had to run a marathon in Mobile, Alabama, the next day.

“Each step I took, I felt like a knife was going through my chest. But I couldn't quit. Alzheimer's patients and their caretakers, they don't have an option to quit.

“It took me more than five hours to finish in Mobile, but it's probably the proudest run I've done,” Knapp added.

Knapp described watching his mother deteriorate as the Alzheimer's progressed as “undoubtedly the most emotionally painful experience of my life.

“But watching the physical, mental and emotional toll it took on my father as he tried to care for her was a close second.”

His father, Denny Knapp, now lives in Florida. One of Knapp's final marathons of the year is the Space Coast event in Cocoa, Fla.

“Dad will be there,” Knapp said. “I'm doing this for him as much as anyone.”

Knapp was never a runner in high school. He played baseball at Butler County Community College.

“In fact, I hated running,” he said. “The worst part of baseball practice was running laps.”

While working on his masters degree at Emerson College in Boston, Knapp got started in running as a means of stress relief.

Before long, he was hooked.

“Once you discover you're getting good at it ... The Running High really does exist. It does become an addiction,” he said. “And Boston is such a great running city.

“I moved to Colorado in 1991 and that's one of the most fit states in America. Everybody runs, bikes, whatever, and training at high altitude makes you that much better.”

When he returns to his roots a few days before the Pittsburgh Marathon, Knapp's friends and family have set up a silent auction of donated baskets May 3 to help raise funds for the fight against Alzheimer's.

The “Chasing Widmills Basket Raffle,” including a bake sale, will take place from noon to 5 p.m that day at the Cabot American Legion Hall on Route 356.

Knapp related that Alzheimer's currently affects more than five million Americans and without a medical breakthrough to slow or stop the disease, that number will triple by the year 2050.

The web address for Knapp's fund-raising efforts is http://act.alz.org/goto/DavidKnapp.

Here are some highlights of the 50 marathons Knoch graduate David Knapp is running in 2014. He turns 50 later this year:• Knapp is scheduled to run marathons in 23 different states, Washington, D.C. and Canada.• Knapp will run three marathons in three days twice — July 4-6 in Oregon and Sept. 12-14 in Lake Tahoe, Calif.• Knapp will run marathons on consecutive days on five other occasions — Jan. 11-12 in Mississippi and Alabama, March 8-9 in Florida, March 15-16 in Washington D.C. and Virginia, March 22-23 in North Carolina and Georgia, Oct. 11-12 in Connecticut and Rhode Island.• Knapp's first marathon was Jan. 11 in Jackson, Ms., and his last will be Dec. 7 in San Antonio, Texas.• Knapp ran seven marathons in March, his busiest month. He will run six in September, five in July.• Knapp ran 40 marathons the year he turned 40.