Randy Wilbur, Ph.D. is the senior sport physiologist at the U.S. Olympic Training Center in Colorado Springs, where he oversees operations in the Athlete Performance Laboratory.  Wilbur knows about the effects of altitude on cyclists not only from scientific studies but from personal experience. He has completed the Leadville Trail 100 Mountain Bike Race -- 100 miles on rocky jeep trails, most over 10,000 feet above sea level.  Coach Fred Matheny shares his comments on altitude training.