Here are the thoughts of some former athletes and experts in the field on sports and concussions:

"We're not trying to say, 'Hate on football.' But we're saying everyone should be educated about the potential of concussion injuries, how to recognize them, and don't allow athletes to return to play when they occur. We have to go further to protect our young men and women on the athletic playing field."

-- Dr. Cindy Chang, a UC Berkeley sports medicine specialist

"It's hard to say that any of this is helping, but I'm doing everything I can to get a little bit better. I'm trying my best to get my family back in a house. We've lost everything. I've lost my business, my home. Welcome to the repercussions of playing in the NFL."

-- Former 49er George Visger, 54, who is receiving treatment for frontal lobe dementia

"I tell people not to get too paranoid because we're all going to bang our heads, and our heads are reasonably well protected inside our skull. But no head trauma is good for the brain. So whenever possible, let's eliminate it. Let's practice football in a way where you don't bang heads. More than 50 percent of head trauma can be taken out of football just by practicing smart."

-- Dr. Robert Cantu, author of "Concussions and Our Kids: America's Leading Expert on How to Protect Young Athletes and Keep Sports Safe"

"The concussion issue in general has become so prevalent. It stems from the professional game but down into the college game. The media attention has brought it down to the Pop Warner level. So many people are playing the game everybody wants to know, 'What are the answers here? How do we separate fact from fiction?' "

-- Former 49ers tight end Brent Jones