What starting position must swimmers take on "take your marks"?

Dive starts (freestyle, breaststroke, butterfly, individual medley):

• On "take your marks", swimmers must immediately take a starting position with at least one foot at the front of the starting platform.
• The position of the hands doesn't matter.

Backstroke and medley relay starts (in the water):

• Swimmers line up facing the starting end with both hands holding the starting grips.
• Standing in or on the gutter, or bending the toes over the lip of the gutter, is not allowed.
• When a backstroke ledge is used, at least one toe of each foot must touch the end wall or the face of the touchpad. Bending the toes over the top of the touchpad isn't allowed.

In both cases the Starter gives the starting signal only once all swimmers are stationary.