Nothing physically special, except good eye sight and a very good knowledge of the rules of tennis.
None, I believe
agility, speed, anaerobic fitness, aerobic fitness, power, strength, flexibility and body size and composition
duties of tournament referee in table tennis
there is only 1 referee in tennis
An Umpire :)
You can be any age
The Tournament Referee officiates over all matches in a USATT (USA TABLE TENNIS) sanctioned tournament.