Hold that Pose

Scholastic ScienceWorld—May 12, 2008 

Contortionists owe their ligaments a big thank you. The large range of motion in their limbs are due to hypermobility of their joints, thanks in part to ligaments that stretch more easily than the ones found in a typical person.

Ligaments attach one bone to another and are made of collagen, which stretches easily but within a limit. "They are meant to be flexible but not too flexible," said Dr. Rebecca Demorest, a sports medicine specialist at Hospital for Special Surgery in New York. "That way your joints don't move out of place completely."

The article appears in the May 12 issue of Scholastic ScienceWorld.