DEVELOPMENT OF A LOW-COST VIDEO VECTOR FOR THE DISPLAY OF GROUND REACTION FORCES DURING GAIT

Video vector systems offer a simple and valuable tool suitable for eva luating and analysing the biomechanics of human motion. These systems are capable of widespread applications in education, clinical evaluati on and research. However, the literature indicated that cut-rent video vector systems are expensive and not widely available. The work prese nted in this study indicates an alternative method of constructing a v ideo vector system which is inexpensive and relatively simple to build . The system uses a VGA to video adaptor to convert computer-generated graphics of the ground reaction force into a video format. This pictu re can then be overlaid on to a video picture of the moving subject us ing a video mixer. By careful positioning of the camera and suitable p erspective drawing of the computer Image a true representation of the relationship between the force vector and the subject can be produced. The system has been Sound to be reliable, versatile and robust and ha s been used for a variety of motion analysis tasks. IL is hoped that t he work contained in this paper will encourage others to construct the ir own video vector systems using similar commercially available compo nents and hence benefit from tile considerable advantages that such a system can offer. This paper describes the design and construction of a simple, inexpensive video vector system which has been shown to be a useful biomechanical technique with widespread applications in the ed ucational, clinical and research environments. Copyright (C) 1996 Else vier Science Ltd for IPEMB.