Toughest call for chair umpire may be lifestyle

Sitting in the prime seat with the authority to rule over millionaire superstars, a tennis chair umpire may have one of the most coveted jobs in the game, but few have what it takes to be successful.

A chair umpire must be able to refrain from going to the toilet for as long as five hours, while constantly looking from side to side and maintaining intense concentration.

"Normally, I don't drink much before umpiring a match. And the tense atmosphere on court always forces me to focus on where every ball lands," said Huang Shan, a 27-year-old Chinese umpire.