Five-time Olympic champion Missy Franklin has retired from swimming at the age of just 23 due to persistent injury.
The 2012 World Swimmer of the Year, announced her decision saying that the shoulder problem has caused her intense pain for nearly three years.
Franklin was a 17-year-old when she won the 100m and 200m backstroke events at the 2012 London Olympics, the latter in a world-record time that still stands more than six years later.
She also took gold as part of two relay teams in London and went on to pick up six more golds at the 2013 world championships, but never improved her personal best times from London.
She struggled to replicate her teenage performances after first experiencing chronic shoulder pain in early 2016.
She still made the US team for the Rio Olympics, however, where she picked up another relay gold after swimming in the heats, before having surgery on both shoulders last year.
"This was perhaps the hardest letter I’ve ever had to write ... Today, I announce my retirement from competitive swimming," Franklin wrote on Twitter.
"I've been in too much pain, for too long, to go through another surgery with a longer recovery time and no guarantee it would even help.
"It took me a long time to say the words, 'I am retiring.' A long, long time. But now I'm ready."
