DEVELOPMENTS IN BIOMECHANICS OF HUMAN MOTION FOR HEALTH AND SPORTS Jorge A.C. Ambrósio and João M.C.S. Abrantes 1 Instituto Superior Técnico, Technical University of Lisbon, 1049-001 Lisbon, Portugal tel.: +351218417680; fax: +351218417915; e-mail: jorge@dem.ist.utl.pt 2 Faculdade de Motricidade Humana, Technical University of Lisbon, 1495-688 Cruz Quebrada, Portugal; tel.: +351214149131; fax: +3512141419129; e-mail: jabrantes@fmh.utl.pt Abstract: The characterization of the human motion has a fundamental importance in scientific areas as diverse as medicine, sports, physical therapy, vehicle dynamics or general engineering applications. One of the most challenging problems consists in the evaluation of the internal forces in the human body and in their control, including muscles, ligaments or anatomic joints, without using intrusive techniques. Experimental procedures based on photogrametry and force platforms are used to collect the data required for the numerical methods, based on inverse dynamics and optimization techniques, to calculate the internal forces. A discussion of the formulations used in the context of the State-of-Art and of the applications presented to sports and health sciences cases helps appraising the collaborative work reported here. Key words: Gait analysis, Joint moments of forces, Redundant muscle forces, Clinical analysis, Multibody dynamics. 1. INTRODUCTION The study of the human motion activities for health, sports, entertainment or for the design of supporting equipment requires the use of experimental and numerical tools that allow identifying the mechanisms of force transmission and their control inside the human body [1]. Sports sciences rely on the knowledge of the kinetics of the human body to devise better training practices and to help athletes to excel [2]. Designers of entertainment and health supporting equipment require that the structures and mechanisms of the human body are well understood and their limits