ESCONDIDO -- For years, Escondido resident Paul Applegate stayed active running 10Ks and playing tennis. On Sunday, Applegate will face a bigger challenge when he attempts to navigate the 26.2-mile course that is the Carlsbad Marathon. But taking on a stiff challenge is nothing new for Applegate, who is waging a daily struggle with ALS.

More commonly known as Lou Gehrig's disease, amyotrophic lateral sclerosis is a progressive neurodegenerative disease that makes even the most basic muscle movements nearly impossible. Applegate, 59, was diagnosed with ALS in July 2004. Several months later, he was forced to quit his job as a financial management executive in the health care industry.

It was actually about a year earlier when Applegate saw the first signs, when he and his family were living in Chico.

"I had a fall in September of '03," he said. "That was probably the first symptom, but I just didn't know it at the time."

An accomplished carpenter, Applegate had another occurrence when he suffered a nasty cut on his hand while sawing wood for a home project.

Applegate's wife, Melonie, realized something was wrong after Paul returned home one day after a cross-country training run.

"I heard him come in, and when I saw him he was covered with mud and leaves from head to toe," Melonie said. "He said, 'The trail just fell away.' "

The trail may have fallen away, but it was difficult to keep Paul from pressing ahead.

A 1964 graduate of San Diego's St. Augustine High, Paul earned a degree in accounting at San Diego State, where he met Melonie, a Kearny High grad. Married for 35 years, the Applegates raised their son Joshua and daughter Stephanie in Escondido, where they had a home on the town's south side, overlooking Lake Hodges.

"I took up running in the early '80s, and I was just as content to go down to Lake Hodges and run against the clock," Paul said. "I loved the atmosphere down there, and the kids and their cousins would ride along the trails with me on their bikes."

There were also his twice-a-week tennis matches with his younger brother Mike. The two would meet on Wednesdays and Saturdays at Serra High in Tierrasanta.

"Tennis was like running for me, in that it was recreational in a sense," Paul said.

His favorite running events were the bridge run over San Diego Bay, the cross-country runs in Balboa Park and a 10K run in Point Loma.

"That run in Point Loma was all downhill," Paul said. "I remember starting at the tip of Point Loma (near Cabrillo National Monument) and finishing at the old Naval Training Center. My time was 43:22, and my knees were talking to me for days after that one."

He will tackle Sunday's distance in a wheelchair, as his last running event was the Almond Run in Chico in October 2003.

"By then I was having trouble with my left leg, so I only ran the 5K," he said.

After Applegate was diagnosed with ALS at a treatment center in San Francisco, the family returned to Escondido last spring. He now receives care at the ALS Regional Treatment Center at UC San Diego.

It was there Applegate was approached by the ALS Association's Greater San Diego Chapter about being part of the group's On a Roll for a Cure program. On a Roll for a Cure is among the Charities in Motion, the program which uses proceeds from the Carlsbad Marathon to benefit local charities.

"I look at this as an honor to be asked to participate," Applegate said. "It's a privilege to represent the association and all the PALS in San Diego and Imperial counties."

PALS are Persons with ALS, and the disease does not discriminate.

"We are now seeing a rise of ALS in people in their 20s," said Joshua, 28. "That's becoming more and more of a problem."

There are about 14 new cases of ALS diagnosed every day. Every 90 minutes, someone loses their battle with the disease, and every 90 minutes another person is told they have ALS. Most patients die within three years of being diagnosed.

"There is no cure," said Lori Butler, executive director of the ALS Association Greater San Diego Chapter. "We can treat and manage the symptoms. Our job is to let the patients know what's available for them."

On Sunday, Paul will do his part in raising awareness in the effort to find a cure for ALS. He will be assisted by family and friends who will form teams for each mile. Melonie's nephew, Brian Scull, is a U.S. Navy physician stationed at Marine Corps Air Station Miramar, and he is scheduled to accompany Paul along the route.

"I'll have my own personal doctor for the entire race," Paul said.

For the final mile leading to the finish line at the Plaza Camino Real shopping mall, the Applegates will be joined by former San Diego resident Jonathon Blais, the 34-year-old triathlete who, despite his own ALS diagnosis, completed the 2005 Ironman World Championship race in Hawaii in October.

Through the difficult times, Paul has received plenty of heartfelt support.

"Melonie is a wonderful wife who has taken on some big responsibilities," he said. "She's a jewel, and my son and daughter have been right there for me."

When Paul reaches the starting line for the marathon early Sunday morning, he will be seated in a new custom wheelchair provided by The Ability Center of San Diego, but he will also have some familiar attire.

"I'll have my old running shoes and my favorite long-sleeved shirt on," Paul said.

Volunteers are welcome to assist with the ALS cause at the marathon. For more information, call the ALS Greater San Diego Chapter at (858) 271-5547, or e-mail info@alsasd.org.

Additional information is available at the chapter's Web site, www.alsasd.org.

By the facts:

WHAT: Carlsbad Marathon (26.2 miles) and Half Marathon (13.1 miles)

WHEN: Sunday, marathon walk start at 5:30 a.m., early marathon start at 6:30 a.m., regular marathon start at 7:30 a.m., half marathon start at 7:30 a.m.

WHERE: Start and finish at Westfield Shoppingtown Plaza Camino Real shopping mall, Marron Road and Monroe Street, Carlsbad

COST: Late entry fees are $85 for the marathon and $55 for the half marathon. Late entries available at PureFitness Carlsbad, 6215 El Camino Real, Carlsbad

INFORMATION: www.carlsbadmarathon.com

Contact staff writer Rick Hoff at (760) 740-3545 or rhoff@nctimes.com. To comment, go to nctimes.com.