explanation.

33.1. Cylinder principle
The cylinder principle is defined as the space within an imaginary cylinder occupied
by a player on the floor. It includes the space above the player and is limited to:
• The front by the palms of the hands,
• The rear by the buttocks, and
• The sides by the outer edge of the arms and legs.
The hands and arms may be extended in front of the torso no further than the
position of the feet, with the arms bent at the elbows so that the forearms and hands
are raised. The distance between his feet will vary according to his height.

Basically, your feet can't be farther apart than your elbows.