How do they do it? Gliding on ice, figure skaters rest only on slim bars of steel. But they can soar into the air, spin and sail using the basic principles of physics.
To perform a jump with more than one rotation, a skater must press against the ice to start the rotation. The force of pressing produces angular momentum, or torque. The skater often twists the body with one foot planted firmly on the ice, then pushes off the ice to propel the body into the air.
For triple or quadruple jumps, skaters must build up as much torque as possible before they take off. This is because of a law of physics known as conservation of momentum. The initial takeoff produces angular momentum, which is stored in the arms and the leg that pushes off the ice. But once the skater is in the air, the angular momentum remains constant unless some external force reduces or increases it.
For instance, the way a figure skater holds his body can affect how fast he rotates. Once in the air, a skater controls his or her rotation speed by closing or opening the body position. A closed position, with the arms and legs pulled in tight against the skater's body, decreases resistance and increases rotation speeds. On the other hand, an open position, in which the arms and legs are allowed to swing away from the body, causes the speed of rotation to decrease. That's why figure skaters open up their body positions when landing jumps: to control the sudden decrease in the rotation speed.
Skating animations courtesy of kingonice.com