Both of the reigning USA national time trial champions will be unable to defend their titles when the 2013 championships take place in Chattanooga, Tennessee next week. David Zabriskie crashed in the warm-up for the Amgen Tour of California time trial in San Jose on Friday, and women's champion Amber Neben went down in a dramatic wreck during the women's race.

Neben told Cyclingnews that she has been diagnosed with a broken hip and ribs, and has major contusions to her shoulder.

The Pasta Zara-Cogeas rider was on a fast, twisty descent in the middle of the race when she appeared to be caught in some gusty crosswinds, and headed into a tight left-hand bend too quickly. After locking up the rear wheel, she ran off the road and clipped the rocky cliff on the left side of the road with her shoulder before being spun around and thrown to the ground.

"I was going well, really well," she said of the race. "Bummer. This hurts literally and figuratively. I'll recover, though. God is always with me as I go through the fires. He doesn't say the road is going to be easy, but he does promise to walk with us and hold us when it gets hard."

The crash comes after a difficult start to the season, which began with a severe case of dysentery at a race in El Salvador. She's had to overcome a case of skin cancer and fought back from numerous injuries throughout her long career.

"Cycling and sport is a microcosm for life. These lessons I learn, these experiences I have can be transferred to business, school, life or other sports. Believe it or not, there can be positive stuff that comes out of adversity. Yes, it stinks... No doubt about it. I do have a big picture perspective that keeps me grounded."