- Sitting volleyball player is 8 feet one inch
- Suffers from excess growth hormones
- Iran is top-ranked team in the world
(CNN)Sitting on the floor, Morteza Mehrzadselakjani's raised arms stretch well over six feet.
Standing up, the Iranian Paralympian measures eight feet one inch, making him the tallest athlete in the history of the Paralympics and the joint second tallest man in the world.
At eight feet two inches, only Turkey's Sultan Kosen is taller.
Sitting volleyball star
While his height has caused Mehrzadselakjani -- known better as Mehrzad -- anguish and suffering his entire life, on the sitting volleyball court it has made him a star.
When he was substituted on in the third set of Wednesday's group B match against Ukraine, the crowd at the Riocentro Pavilion exploded.
Playing as the setter, Mehrzad served and spiked the team through to match point, when he smashed an ace that sealed Iran's victory in straight sets 22-25 26-28 20-25.
His addition to the team this year, already ranked no. 1 in the world, has strengthened Iran's bid for gold -- the Iranians have won five gold and two silver medals in the sport's seven Paralympic appearances.
But Mehrzad's competitive advantage has come at a hefty cost. He suffers from acromegaly, a rare condition caused by excess growth hormone.
At the age of 16, he already measured over six feet two inches. A year earlier, a serious pelvis fracture from a bicycle accident stopped his right leg from growing -- it's now six inches shorter than the left, making it difficult to walk. Mehrzad normally uses a wheelchair or crutches to get around.