Missy Franklin has announced her retirement from swimming. Photo: REUTERS/Michael Dalder

LOS ANGELES – Former world and Olympic swimming champion Missy Franklin of the United States announced her retirement from competition on Wednesday, citing a nagging shoulder injury that would have required surgery.

Franklin, 23, announced her decision on Twitter and revealed details in an open letter given to ESPN.

“This was perhaps the hardest letter I've ever had to write,” she tweeted. “There are so many words to say and I thank you all for letting me share them with you, and for your continued support. Today, I announce my retirement from competitive swimming.”

Franklin walks away with five Olympic gold medals and six overall plus 11 world titles in her career.

She captured 2012 London Olympic gold in the 100- and 200-meter backstroke and 4x100 medley relay plus 4x200 free relay crowns at London and in 2016 at Rio.

She also collected world crowns in the 200 backstroke in 2011 and 2013 and the 100 back and 200 free in 2013 as well as helping seven US relay teams to world titles, including three in a row from 2011-2015 in the 4x200 freestyle.

Franklin said in her letter she battled through intense shoulder pain ahead of the Rio Olympics and underwent surgery on both shoulders in early 2017.

She worked on a comeback this year but was diagnosed with severe chronic tendonitis of the rotator cuff and biceps tendons.

“I'm ready to not be in pain every day,” Franklin wrote. “I'm ready to become a wife and, one day, a mother. I'm ready to continue growing each and every day to be the best person and role model I can be. I'm ready for the rest of my life.”

Agence France-Presse (AFP)