You might have seen the video of Russian diver Nadezhda Bazhina doing a back flop in the 3m springboard preliminary at the Rio Games.
Bazhina, who has won medals in multiple European championships, received a zero for her dive in the Rio round on Friday which caused a stir on social media.
Many Twitter users felt she should have been given some points for the attempt.
But to those familiar with diving there was nothing shocking about the score. According to the judging rules, a zero score is defined as "completely failed."
“If the correct dive is performed, even if it is deficient or unsatisfactory, a diver would receive a score," Jennifer Lowery, senior public relations director at USA Diving said in a statement. “If the correct dive is not performed, it is considered an incomplete or failed dive.”
Bazhina was unable to execute the three and a half summersaults she was supposed to. She landed in the pool on her back, her feet hitting the water before her hands.
While not an every day occurrence, scoring a zero is not rare or uncommon at national and international meets, Lowery said.
At the 2012 Olympics in London, Germany's Stephan Feck scored a zero in the men's 3m springboard preliminary round after landing on his back.
Two Filipino divers, John Elmerson Fabriga and John David Pahoyo, had back to back back-flops resulting in two zeros at the 2015 Southeast Asia Games in Singapore.