But when the 63-year-old described his symptoms to one of his students, oncologist Niall Tebbutt, it immediately set off alarm bells.
Professor Tebbutt ordered a PSA blood test, and subsequent diagnostic assessments confirmed Mr McClarty had stage four prostate cancer.
"It just devastated me," he told AAP.
Mr McClarty is sharing his story so that more men will take control of their health.
His cancer has spread to his hip bones and while he is still undergoing treatment, he has been given only six to 10 years to live.
"If I could go back and do the tests for the first time (earlier), it would be a totally, totally different outcome," he said.
"I ignored it, I'm late and now I'm at stage four because of that."
Prof Tebbutt said the Kooyong Lawn and Tennis Club head squash coach and professional player would never have thought to go to a doctor because he was fit and healthy.
"This is the reality of life ... you can keep it healthy, but cancer affects everybody," he said.
"He knew there was a problem and it wasn't going to go away on its own."
Mr McClarty's message for men is clear.
"It's pretty simple, if you're 50 and over, get tested and get tested regularly," he said.
"That's the starting point, get your PSA test."
Prof Tebbutt is urging men with any concerns over their health to visit their GP.
"If you have persistent, progressive symptoms of any kind, that's something that does need to be assessed for a range of different conditions," he said.
The pleas come after a report by the Lancet Commission on Prostate Cancer, which projects cases of the disease will double by 2040.
However, the Urological Society of Australia and New Zealand (USANZ), says while the findings are alarming, Australia is in the best position to deal with the increase in cases thanks to the availability of advanced diagnostic tools.
The society's Weranja Ranasinghe cautioned that this needed to be coupled with greater awareness about prostate cancer.
"One of the biggest determinants is the awareness, and also we really need some better guidelines in terms of who to offer PSA tests to," he said.
"The awareness of prostate cancer can be much better."
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