Because the F200 on a steep banked track like indoor tracks is essentially a hill climb in a big gear followed by an all out sprint, you need fitness to be able to climb the hill and have enough in reserve to punch out the F200. Pretty much everyone will do the F200 in a bigger gear than what they would normally use for say sprint races or scratch races. That means you're hill climbing in a bigger gear compared to what you would normally use (total opposite to a road climb), and that is a taxing effort, and then you have to follow it up with a full gas sprint.
The gearing comes down to experience. A gear too small will get your wind up done easier but your F200 will spin out and be slower. Too big and you punish yourself in the windup and leave not enough for a quality F200.