Playing powerhouse volleyball for more than 20 years at an elite level has damaged Kerri Pottharst's knees beyond repair and forced her to announce her retirement from international competition.

Many thought the 37-year-old would succumb to her much publicised biological clock.

But in Sydney Pottharst said expert medical opinion last week confirmed career-ending cartilage degeneration behind both knee caps.

She said the damage could not be satisfactorily repaired for a tilt at defending the Olympic gold medal she won with Natalie Cook in Sydney.

"I did all my damage on the indoor courts early on, and it just continued to get harder and harder," Pottharst said.

"Over the last couple of months I had to take anti-inflammatory tablets just to keep the pain away to play the national tour just gone by."

It was Pottharst and Cook's sixth consecutive national title.

She estimated she had jumped and landed 45,000 times a year since her indoor debut for Australia in 1982.

Pottharst said she agonised for months over her decision to quit with the deadline of the July Olympic qualifying hanging over her head.

The issue came to light in September last year as the pair celebrated the first anniversary of their gold medal win at the 2000 Olympics.

Brought to you by AAP © 2024 AAP