Nicholas Long felt ill before his final ride. Alise Post got unclipped down the last straight in her race.
The American riders each still managed to secure third-place finishes at the recent world championships, good enough to clinch spots on the U.S. Olympic team.
After getting left off the podium at worlds in 2015, the United States has a little momentum with the Summer Games in Rio coming up.
''Pretty happy, to be honest,'' said Jaime Staff, USA Cycling's BMX director. ''Got two in the final. Just to get two in the final ... and the podium, makes my job easier. Obviously, a lot of pressure on these'' bikers.
BMX racing emerged as a sport in Southern California in the 1970s. It became an Olympic sport in 2008, when the United States picked up three medals.
But Team USA has never won gold. Americans were shut out from the medal stand completely in 2012 in London.
Back then, Post finished 12th, while Brooke Crain was the United States' best finisher on the women's side in eighth. This year, Post seemed like a good bet to get to Rio regardless of what happened at worlds in Medellin, Colombia, by virtue of USA Cycling's power rankings.
''With Alise, there's at least more expectations with her to podium, I think, just because she's one of the best three in the world,'' Staff said.
Post rode the perfect lap in the semifinals at worlds but didn't get off to the best start in the final, Staff said. Still, Post was second on the last straight behind eventual winner, home country favorite Mariana Pajon, before falling back a spot after getting unclipped.
''I am walking away ... healthy and officially qualified to Rio, so I'd say it was a success!'' Post said after the race. ''Now time to get back to work.''
Long also had a good chance to get to Rio because of the power rankings. At Medellin, he powered through illness to clinch his spot with a third-place finish.
Long and other riders had been throwing up, Staff said, at the venue with an elevation of 5,000 feet. While not extreme, it's still high enough to have an impact on performance.
''He was really hurting before the main,'' Staff said. ''He really dug deep.''
Two other top U.S. riders missed worlds but still appear to have good chances at making the Olympic team. Crain has a broken fibula, while Connor Fields, who finished seventh in the men's final in 2012 in London, has a wrist injury.