Palavras-chave ginástica online, Second Life, OpenSimulator, Mundos Virtuais, Kinect, Captura de movimentos, Interação Humano computador, interfaces naturais Palavras-chave ACM H.5.1 Multimedia Information Systems; H.5.2 User Interfaces Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. Fernando Cassola INESC TEC / UTAD Universidade de Trás-os-Montes e Alto Douro Porto Portugal fernandocassola@gmail.com