Last summer, after learning that he needed a kidney transplant, reigning 110-meter hurdles gold medalist Aries Merritt picked up his phone and called his older sister LaToya.

Before he even had a chance to ask her anything, LaToya said she would immediately check to see if she would be a match to become his donor.

She was.

Aries Merritt had learned in 2013 that he was suffering from both a kidney disease and a genetic disorder that was attacking his kidneys. The condition caused him to feel weak and eventually worsened to such an extent that doctors said it was doubtful whether Merritt would be able to compete again. How could he when he was living with his kidneys functioning at less than 20 percent?

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Recovery from the September 2015 kidney surgery took awhile—especially after a complication developed and Merritt had to go back under the knife again—but now, less than a year after receiving his sister’s kidney, Merritt was focusing on defending his gold medal in Rio.

While that may have sound unlikely at first, consider this: about a month after that fateful phone call to his sister, Merritt flew to Beijing for the 2015 World Championships, and prior to the competition, told the public about the condition he was suffering from.

Shocked that he was still racing, Merritt’s teammates were even more stunned when he finished the competition with a new medal in hand.

Sure, it wasn’t gold, but Merritt was running on fumes. Now back to nearly 100 percent kidney function, the 30-year-old hurdler told reporters in May that his strength has returned and he’s confident he’ll be ready for Rio.

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Merritt was certainly feeling ready at the Track & Field Olympic Trials, however, in a photo finish, the Marietta, GA native missed out on an Olympic berth by just .01 seconds.

Not being able to defend his gold didn’t put a damper on Merritt. Speaking to Louis Johnson after the Trials, Merritt said “it’s a blessing just to be here because many, many times they told me I’d never run again and here I am doing things that’s really impossible 10 months after a kidney transplant, but I’m blessed and happy I’m out here competing…and doing what I love.”

To learn more about all Olympic hopefuls, visit TeamUSA.org. The Olympics begin August 5.