Former San Francisco 49ers wide receiver Dwight Clark has revealed that he has been diagnosed with Lou Gehrig's disease.

Clark is best known for his leaping touchdown catch during the NFC Championship Game in 1982.

"In September of 2015, I started feeling weakness in my left hand," Clark wrote in a statement on former 49ers owner Ed DeBartolo, Jr.'s website. "I was mildly paying attention to it because since my playing days, I've constantly had pain in my neck. I was thinking it was related to some kind of nerve damage because it would just come and go.

"After months of tests and treatment, I got some bad news," he continued. "I was diagnosed with amyotrophic lateral sclerosis. I have ALS, also known as Lou Gehrig's disease. Those words are still very hard for me to say."

Clark, 60, says he has also lost significant strength in his right hand, midsection, lower back and right leg and says he "can't run, play golf or walk any distances'' and that "picking up anything over 30 pounds is a chore.'' He adds "that the disease seems to be progressing more slowly than in some patients.''