Martin learned humility, and eventually started the long road back to recovery, her sights set on London in 2012. In May of this year, Arielle Martin's recovery was complete. She secured the first women's spot on Team USA's 2012 Olympic BMX race team following the UCI BMX World Championships in Birmingham, UK. Finishing fourth place in the semifinals, Martin grabbed the "Automatic Nomination" slot.

"Deep down I knew at that moment that I was going to London. It freed the monkey that had been on my back for four years," said Martin following the race. Four days later, Arielle Martin was back in the U.S. and entering the first weeks of training for the London Games at the Olympic Training Center (OTC) in Chula Vista, Calif.

Martin did the press rounds, trained constantly through June and July, and was in good spirits entering into the finals days of training before her trip to London. Last week, she donned her Team USA Olympic race uniform for the first time and posed for a photo with her Intense bike, adorned in a Stars and Stripes print. "It's finally feeling real now," she said.

On Tuesday, it all came crashing down, again.

During a final practice session at the OTC, Martin suffered a mechanical malfunction and crashed. She was rushed to Mercy Hospital in San Diego, Calif., and deemed unable to compete in the Olympic Games. Haro rider Brooke Crain stepped in as Martin's replacement, and joined Team USA on their flight to London on Wednesday.

According to representatives for Martin, "She has a severe laceration to her liver and pneumothorax (collapse) of the right lung. While her injuries were initially life-threatening, she has been upgraded from intensive care to a trauma unit. She is wishing her teammates all the best in London."

Fans and fellow racers immediately realized the impact of Martin's crash earlier this week. 2008 Olympic BMX athlete Mike Day reached out via Twitter to say, "Absolutely devastated for Arielle after missing out on Beijing to now crash and be out of London."

Martin's replacement, Brooke Crain, shared that sentiment. "I'm devastated for my teammate," said Crain. "She deserves to be here more than anyone. I will represent her, my country and live my Olympic dream."

Meanwhile, Martin remains in Mercy Hospital. She is expected to make a full recovery and could potentially be back racing by the end of the year, her sights most certainly set on the 2016 Summer Olympics in Rio de Janeiro, Brazil.