One Colombian diver was left needing medical attention over the weekend after a complicated routine went horribly wrong.

Juan Guillermo Rios and Victor Ortega of Colombia were attempting a tandem reverse 3½ somersault in the synchronised 10 metre platform event at the FINA Diving World Series in Kazan, Russia, when Rios made a painful entry to the pool.

Misjudging the second rotation, Rios landed flat on his back on the surface. The divers' coach was seen holding his head in his hands after the failed attempt.

The athlete attended the medical clinic after coughing up blood, but later reassured fans that his injuries were not severe.

"Hello. I send a greeting, please be aware of my health," Rios said. "I'm much better, it was not serious."

Rios should make a return to the pool for the World Series in England from May 1 to 3.

smh.com.au