Associated Press
American BMX racer Donny Robinson will try to win an Olympic medal when the sport debuts at the Games in China.

American cycling star Donny Robinson has heard it for years.

It seems like such simple physics. At 5-foot-5, isn't he too short to be an elite BMX racer? Doesn't his 150-pound body simply lack the strength and power to compete against men several inches taller, 50 or 60 pounds heavier and who have far more muscle packed onto their frames?

Somehow, the answer is no.

"People have no clue what can be accomplished," Robinson said, "when you want something bad enough."

So next August in Beijing, Robinson wants to stand tall — atop the medal podium with Olympic gold around his neck.

The 24-year-old rider from Napa, Calif., is one of the best BMX racers in the world and part of a powerful American team that plans to dominate when the niche sport hits the Olympic stage for the first time this summer. The U.S. squad is ranked No. 1 by the International Cycling Union, and the diminutive Robinson is a big reason why.

He's currently No. 2 in the worldwide BMX rankings — only behind fellow American Mike Day — and won a test event at the newly built Beijing Olympic track a few months back, giving him plenty of confidence heading into the biggest year of his career.

If he gets one of USA Cycling's Olympic spots, he'll be a gold medal favorite.

"When I first got to that track in Beijing, the place was completely empty and my jaw was hanging for a good half an hour," Robinson said. "It really hit me that this is the place. This is the place where all my dreams can come true."

One of his dreams already is: BMX is going mainstream.

He was 6 when he started racing, and even into his late teens, the Olympics wasn't something BMX racers like Robinson thought about. Their sport — pedaling single-gear bikes on 350-meter dirt tracks with steep start ramps, challenging jumps and banked curves — was thought by many to be a long shot for the Olympic program.

But in 2003, the IOC noticed of BMX's surging popularity, particularly among young athletes, and added it to the Beijing lineup.

Right then and there, Robinson's priorities immediately changed.

He abandoned the cliche, one-race-at-a-time approach that worked for years. From now until August, it's all about the Olympics.

"Having the world finally see our abilities and realize that we've spent our whole life to be at this point, it's just an amazing feeling," Robinson said.

He makes BMX sound easy.

It's nothing close to easy anymore.

Gone are the days where the sport's "tricks" include relatively simple things like wheelies, kickouts and bunnyhops. No, it takes a special sort of athlete to survive in the sport now. Races are grueling and can tend to mimic roller derby on dirt.

And the tracks — including the massive, steep one in Beijing — test all limits.

"I had a rider who was ranked in the top 10 in the world," said Pat McDonough, USA Cycling's director of athletics. "We went to the Olympic track in Beijing, with its huge start ramp. She got up there and retired. She got up there and froze for 45 minutes. She told me that if this is where the sport is going, she's done. It's almost at the point where you've got to be completely nuts ... freakin' crazy to do this now."

Robinson doesn't describe himself as nuts or crazy.

But he races that way. He has to, or else winning wouldn't be an option.

Once riders leave the starting gate, the next few seconds on a BMX track are, at best, controlled chaos. They're often side-by-side, inches apart, pedaling furiously. They usually go over jumps en masse; if one racer lands awkwardly and bobbles, then the riders trailing at that point typically crash as well.

So there's tons of luck involved just to navigate the course while remaining upright.

"It's like anything else," Robinson said. "The more you work, the more successful you'll be."

His record — with a couple dozen race wins as a pro, a few titles and the current No. 2 points ranking — has proved that.

It also proves that his size won't deter him from his plans to climb that Olympic mountain in Beijing, either.

"These guys are bigger. So why don't they beat me every single time? It's always in my mind," Robinson said. "So I train harder, I work harder and it's all mental. If you let it get to you, then you've already lost the race. And I won't let that happen."