NEWS: Venus Williams Goes Nude For ESPN, Talks About Disease That Kept Her From Playing Tennis (Video)

Five-time Wimbledon champion Venus Williams is on the cover of ESPN Body Issue, out in July.

In addition to stripping down for the issue, Williams also exposes harrowing new details about her ongoing battle with Sjogren's syndrome, an autoimmune disorder that causes white blood cells to attack a person's moisture-producing glands.

"At my worst point, I wasn't able to play tennis at all," says Williams. "Just the whole quality of my life was compromised. You are so tired it hurts. You have to accept that you're never going to be 100 percent."

Williams, who was forced to stop playing for more than six months in 2011-12 because of the illness, reveals in the interview how she got her body in shape for the magazine's nude photoshoot and how she was able to work her way back up the rankings.

Oh man, this is the real deal. It didn't dawn on me until right when I walked on set that I would have to be without clothes. If I would have thought about it before, there may have been a little less of a chance.

In the past, I would train until I died. Now, because of Sjogren's syndrome, I have to be careful. If I train too hard, then I won't be able to do anything the next day. There would be times when I'd park my car at home and I fell asleep behind the wheel because I was so tired! It's a balance between pushing myself as much as I can and being reasonable about what I can achieve and what my body will tolerate.

You are so tired it hurts. At my worst point, I wasn't able to play tennis at all. Just the whole quality of my life was compromised -- and uncomfortable. It's very difficult to understand unless you've gone through it. Especially as a professional athlete, there's never any acceptable excuse. You push and you push and you'll die on the court if you have to, but you get it done. The whole experience is just foreign as an athlete. You have to accept that you're never going to be 100 percent. So, how do you get past those roadblocks?

I wouldn't say I "enjoyed" the challenge. But I'm up for the challenge. Sjogren's syndrome has been a life-changing experience, that's for sure.