Example:When a figure skater glides on one foot, the leg that is on the ice is called the skating leg. The leg that is lifted is called the free leg. The arm that corresponds to the skating leg is the skating arm. The arm that corresponds to the arm that is off the ice is the free arm.
In this photo, 2012 Olympic Figure Skating Champion, Kim Yu-Na, holds her skating arm out to the side. Her free arm is lifted above her head.