By age 3, preschoolers have developed enough motor skills to participate in organized games and some sports. They are now capable of hopping and standing on one foot for as long as five seconds, although this demands more concentration than routine activities like walking and running.
Shelov, S. P. (Editor-in-Chief). (2004.) Caring for Your Baby and Young Child: Birth to Age 5. The American Association of Pediatrics. Revised edition. New York: Bantam Books.