Thaddeus Neumann, 41, a University of Maryland graduate whose exploits in the world of sports for disabled athletes led to a career as a motivational speaker, died of a brain seizure June 1 at the University of Virginia Hospital.

He was taken to the hospital by helicopter from Lake Anna, Va., where he had collapsed while visiting relatives.

Mr. Neumann, who as a result of diabetes was blind and for a time couldn't walk without corrective shoes, skied regularly in national and international competitions sponsored by such organizations as the National Sports Center for the Disabled. In the 1990s, he won gold, silver and bronze medals in the downhill skiing event, for which he used a mono-ski, which has a seat mounted to a single blade.

There seemed to be no outdoor recreation he would not at least try, said Andreas Neumann, who watched his brother enthusiastically take up hang gliding, tandem kayaking, whitewater rafting, tandem mountain biking, rowing, sailing and tubing.

"He really had a go-for-it attitude that was present in his everyday life," Andreas Neumann said.

Overcoming adversity was one of Thaddeus Neumann's central themes in speeches he gave at public schools, universities and corporate functions across the country. He spoke of determination, commitment, setting goals and never giving up hope. Mr. Neumann, who lived in Fraser, Colo., formed a business to manage his public speaking requests and created a Web site to chronicle his personal story, both of which bear the same name: Pursue Your Happiness.

Happiness for Mr. Neumann came in the exhilaration he experienced from participating in extreme sports. And he was determined to live his life to the fullest despite his physical disabilities, Andreas Neumann said.

His health problems began with juvenile diabetes diagnosed when he was 7. He was born in Washington, the second of five children in a family that lived in North Bethesda.

By the time he was a student at Charles W. Woodward High School in Bethesda, he had contracted a degenerative disease called Charcot-Marie-Tooth, which affects the body's extremities. The disease led to atrophy of his calf muscles and deformed feet to the point he had to crawl if he wasn't wearing orthopedic shoes.

Within a year of his 1985 graduation from the University of Maryland with a degree in accounting, he lost his vision from diabetic retinopathy and suffered kidney failure. He spent a grueling year and a half on dialysis before undergoing kidney transplant surgery.

The success of the operation lifted his depression and led to new optimism about his future. Mr. Neumann began working in Washington at the Columbia Lighthouse for the Blind, teaching other visually impaired people how to use computers.

He moved to Colorado after a vacation trip there renewed his childhood interest in skiing. He underwent corrective surgery on his feet, followed by physical therapy that helped him regain a limited ability to walk. But he also suffered several diabetes-related strokes, which caused partial paralysis, and had quadruple bypass surgery.

Through it all, he remained resilient, according to his friends and family.

"Every time I have a setback, I set new goals for my life because I do want to continue to encourage people and give people hope," he wrote for his promotional materials.

Survivors include his mother, Renate Neumann of North Bethesda; two brothers, Mathias Neumann of Darnestown and Andreas Neumann of Venice Beach, Calif.; and two sisters, Melissa Gruber of Breckenridge, Colo., and Petra Pope of Grand Junction, Colo.