hi there.this is purely my own thoughts bt the reason centres r usually the captain is that that position requires alot more skills than the others, in saying that i in no way mean it is the most important tho. centres not only need the skill of attack but they need to be able to switch from attack to defence at the drop of a hat. they need tohave a good sense of the game and reading it b able to work wth their d and a team mates as the centre position is the only one to go newhere on court but the circle. their fitness level must be high and their catching and throwing must b accurate. hope this helps???