With every pedal stroke of his modified recumbent tricycle, one Clear Lake man considers himself blessed to still be able to do an activity he loves despite a sobering medical prognosis.

"It's my freedom," lifelong cyclist Craig Humburg said, as he blinked back tears.

The Mason City Globe Gazette reports (http://bit.ly/1oepipM) Craig, a 1973 graduate of Clear Lake High School, was diagnosed with amyotrophic lateral sclerosis (ALS) in 2006. A carpenter for nearly 30 years, he first noticed something was wrong when his right hand wasn't functioning correctly.

Commonly known as Lou Gehrig's Disease, ALS is a fatal progressive neurodegenerative disease that affects the function of nerves and muscles. It causes weakness, degeneration and paralysis of muscles and affects speech, swallowing and breathing.

About two in every 100,000 people have ALS, with approximately 5,600 people in the U.S. diagnosed each year, according to the ALS Association. Researchers are still investigating possible risk factors, but the disease can strike anyone and occurs throughout the world.

Diagnosis most commonly occurs between the ages of 40 and 70, but advancement differs from individual to individual.

Craig considers his progression slow, since he is still able to walk and bike, but muscle atrophy limits the use of his arms and hands. At times, he struggles with speaking.

At the time of his diagnosis, doctors gave him three to five years to live. Friends and church family at Zion Lutheran banded together to complete an addition on the Humburgs' Clear Lake home, which includes a wheelchair-accessible bedroom and bathroom, something Craig hasn't needed quite yet.

Eight years later, the 59-year-old is proud to say he's still conquering about 4,000 miles a year on his bike. His recumbent is tailored to his needs, with armrests added and modifications made to the shifting and braking controls.

He's out on the road five days a week and wakes up early to bike around the lake. Afterward he'll polish off an ice cream breakfast.

"I make a big blender full of malt and protein drink so I get a lot of calories," he said. "I'm not afraid to eat a lot of things that most people wouldn't."

Losing weight in both muscle and fat is common as ALS advances, but recent scientific research suggests eating a diet high in carbohydrates and calories may slow the disease.

He'll travel to Garner and back in the afternoon. He's racked up about 1,200 miles so far this year and plots his routes based on which direction the wind is blowing.

Some days he'll also trim his yard with a self-propelled mower.

Colder months are filled with a lot of walking, which Craig humorously describes as "so slow" and "not a good means of transportation."

Whatever the weather, Craig likes to stay active, especially with his 5-year-old granddaughter Zoey.

He has been babysitting her since she was born, and said the little girl knows exactly when her grandpa needs a helping hand.

Craig's wife, Linda Humburg, said Zoey will regularly assist with pulling off shirts, zipping jackets or putting on stocking hats.

While Craig said there's mixed viewpoints on what type or how much exercise individuals with ALS should do, he says he has nothing to lose. Some studies indicate exercise can help delay the progression of ALS.

"I'm still walking and talking so I can't complain a whole lot," he said. "There are a lot of people who are a whole lot worse off than I am."

For a year and a half, he took Riluzole, the first treatment shown to alter the course of ALS for at least a few months, but said he saw little difference in his symptoms. The drug costs upwards of $1,200 a month without insurance.

He's hopeful there will be a cure, but doesn't think he'll live long enough to see it.

A monthly support group in Mason City helps connect him with other area individuals with ALS, but Craig said it's difficult to see others gradually lose their strength.

"I don't know why I'm still going, but I guess God had a plan for me," he said. "Someone is watching out for us, because we have been real lucky."

Information from: Globe Gazette,http://www.globegazette.com/