Studies of Relationships Between Lumbar Disc Pressure, Myoelectric Back Muscle Activity, and Intra- Abdominal (Intragastric) Pressure

Abstract

Linear relationships between lumbar disc pressure and myoelectric back muscle activity and intra-abdominal pressure have been studied in order to select the best predictor. The data on which the analyses are based have been collected in a number of previous studies of symmetric and asymmetric loading of the trunk as well as heavy lifting in static postures. High correlations are found for both predictors, with the myoelectric signal amplitudes giving the highest. The regression lines differ between symmetric and asymmetric loading postures. This favours the use of myoelectric signal amplitudes, since the differences between the sides can be used to indicate asymmetric loading. The regression equations could not be extended to include heavy lifting, which obviously constitutes a separate type of loading.