President Bush is getting plenty of bike time during his ranch vacation and next weekend he even gets to hit the trails with seven-time Tour de France (search) winner Lance Armstrong (search).

Armstrong told ABC's "This Week" on Sunday that he'll travel to Crawford, Texas, next Saturday to ride mountain bikes with the president around Bush's ranch.

"It's a dream scenario for me," Armstrong said. "Now that President Bush doesn't run anymore, he rides his mountain bike fanatically. People wonder why he's stays at the ranch so long, it might be the mountain bike trails."

It also must be a dream scenario for Bush to ride with Armstrong, a fellow Texan and cancer survivor who last month won his most recent Tour de France. Bush has become an avid biker in the last couple of years, after a knee injury forced him to give up his jogging routine.

"Like a lot of baby boomers, my knees gave out," Bush explained to seven journalists who accompanied him on a two-hour ride Saturday. "And I believe that mountain biking is going to be an outlet for a lot of people my age. I'm 59, and people are going to realize you get as much aerobic exercise — if not more on the mountain bike — without being hobbled."

Bush said he considers exercise good preventive medicine and "part of living a disciplined life." He said he is trying to set an example to more Americans to exercise.

"What it takes is organization and discipline and setting priorities," Bush said. "And I think exercise ought to be one of the top priorities for Americans."

Bush said he prefers mountain biking to road biking, where riders often shave their legs and wear Lycra shorts. "There are certain things that age brings with it, and not wearing the formfitting Lycra short is one of them, if you know what I mean," Bush joked with the reporters.

Armstrong said although the president certainly couldn't whip him, he's impressed with how seriously Bush takes the his new sport.

"I know people who have ridden with him," Armstrong said. "I can tell you he's one very competitive guy. Very competitive, there's no talking. A few minutes of warm up time, a little chitchat, then you go."

Armstrong also spent some time during the Tour de France with Bush's former rival, 2004 Democratic presidential nominee John Kerry (search), who followed in a car during the final time trial. Armstrong said he's not taking sides in politics even though he's opposed to the war in Iraq.

"As a survivor, I think we would be better spending money on an illness like cancer," he said.