Dual Olympic silver medallist Christian Sprenger has announced he will retire from competitive swimming effective immediately.
Sprenger, 30, has spent almost a decade on the Australian Dolphins Swim Team after making his debut at the 2006 Commonwealth Games in Melbourne, winning a gold medal in the 4x100 metre medley.
He won a silver medal in the same event at 2008 Beijing Olympics, before claiming silver in the 100m breaststroke four years later in London.
Sprenger said he could have made a third-straight Olympic Games if it was not for a lack of motivation and an ongoing shoulder problem.
"The injury I sustained in 2014 really took a bigger toll on me than I thought it would," Sprenger said on Thursday.
"After returning in 2015, after almost four months out of the water, I worked hard to get back what I had lost, but although I may have thought I wanted it, it wasn't enough.
"Towards the end of 2015, my breaststroke just didn't feel how it used to, and I became more and more frustrated.
"The Olympic gold is the only thing missing from my collection, but in this sport, if the mind and body are not perfectly in sync and focused beyond capacity, the performance will not come.
"Ultimately for me, I am not there anymore, and although I may be good enough to make the Olympic team, I can't just be a number on a team, that is not who I am."