Despite a recent make-over, age may finally be catching up with Michelangelo's David, who celebrates his 500th birthday on Wednesday.

Over the next few months in Florence, the 4.1-metre marble statue of the biblical hero will be discussed and feted in dance and musical performances, public debates, art exhibitions and workshops, all of which kicks off Wednesday.

But after five centuries of representing the epitome of male beauty, it seems that David may not be so perfect after all.

In May, an art restorer completed a cleaning of David, removing the grayish grime that had developed over the years.

During the restoration process, which included digital mapping to examine cracks and blemishes, a research team discovered a weakness in the statue's right ankle, which supports several tonnes of dead weight. Engineers are conducting resistance tests on similar marble to find ways to shore up the faulty joint.

In addition, a British fitness expert has taken aim at David's posture, which is actually very poor because of the bend in his left hip.

"Standing like that weakens the right side," Alan Herdman, the fitness guru who helped introduce Pilates to Britain, told Agence France-Presse on Tuesday.

"His pelvis is wrong; it is thrust forward and pushing into the right hip."

It's little wonder that David may be finally showing his age. He spent more than 300 of his 500 years outdoors in the Piazza della Signoria, exposed to riots, vandals, the elements, a previous "cleaning" with acid and pigeons.

Despite the wear and tear he has suffered, the now-gleaming homage to male beauty draws more than a million visitors to the city's Accademia Gallery, where he has been on display since 1873.

For Wednesday's opening event of the 500th anniversary celebration, hosted in a 14th-century city hall, guests were scheduled to read from the journals of Giorgio Vasari and Luca Landucci. The two well-known 16th-century artists from Florence were on hand at the unveiling of Michelangelo's statue on Sept. 8, 1504.