In the old days, you didn’t choose to be an umpire. You got stuck doing it.
Those days are long, long gone.
The modern umpire must not only be one of the better athletes on the field, he needs to be mentally sharp. One second the umpire is determining the point of attack and watching the action there. The next he is dodging large, muscular players oblivious to his presence but seemingly hell-bent on running him over.