An arm wrestler has a 19 inch (49cm) forearms that is big enough to fit a basketball in each hand. Tests have been conducted to discover what makes Jeff’s arms so large, as family photographs show he was born with over-sized limbs.

Having looked for signs of gigantism and elephantiasis, the University of Minnesota concluded that there were no signs of the disease or abnormalities.

Jeff’s Dabe wife, Gina, said he was simply born that way. The arm wrestler has been competing in arm wrestling tournaments since the 1980s, with his giant paws giving him a natural advantage.