USING SIGNAL/NOISE RATIOS TO CHECK ATHLETE'S CG VALUES

Abstract

The purpose of this investigation was to indicate the reliability of total body center-of-gravity values calculated from cinematographical data . In biomechanical research studies in which film data are utilized, researchers have often overlooked the precision of the digitizing procedure employed in obtaining the data. Previous approaches to establishing reliability for the digitizing procedure have been single-faceted; that is, only intraploter or interploter error was investigated. Since there are several error sources, an approach should be taken that not only determines the contribution of each source to measurement imprecision but also determines the interactions of these sources. The application of generalizability theory, formulated by Cronbach et al. (I972 ), provides such a technique. By examining the sources of variability of total body center-of-gravity values calculated by the segmental method, signal/noise ratios were calculated to indicate the relative precision of the digitizing procedure.