Reliability and Validity of the Computer Science and Applications Accelerometer in a Mechanical Setting Søren Brage Institute of Sport Science & Clinical Biomechanics University of Southern Denmark Main Campus: Odense University; and The Institute of Public Health Cambridge University, England Niels Brage Institute of Sport Science & Clinical Biomechanics University of Southern Denmark Main Campus: Odense University; and Department of Mathematics & Computer Science University of Southern Denmark Main Campus: Odense University Niels Wedderkopp University Hospital of Odense University of Southern Denmark Karsten Froberg Institute of Sport Science & Clinical Biomechanics University of Southern Denmark Main Campus: Odense University Accelerometry has been proposed as an objective method for measurement of physi- cal activity. Intra- and inter-instrument reliability and validity of the Computer Sci- ence and Applications (CSA) Model 7164 accelerometer, along with the nature of the analogue filter in the device, was studied with sinusoidal movements in a mechanical MEASUREMENT IN PHYSICAL EDUCATION AND EXERCISE SCIENCE, 7(2), 101–119 Copyright © 2003, Lawrence Erlbaum Associates, Inc. Requests for reprints should be sent to Søren Brage, Institute of Public Health, Cambridge Univer- sity, University Forvie Site, Robinson Way, Cambridge CB2 2SR, England. E-mail: sb400@medschl.cam.ac.uk