In healthy subjects, the sitting position can be used to validate the postural effects induced by wearing a lumbar lordosis brace.

AIM OF THE STUDY To assess the validity of the sitting position when testing lumbar braces for the maintenance of lordosis. PATIENTS AND METHODS Twelve young adult subjects participated in the experiment, in which they were seated on force platform. The four experimental conditions (with or without a brace and with or without enforced lordosis) were chosen in order to distinguish between the roles played by lordosis and the brace, respectively. The trajectories of the centre of pressure (CP) were analyzed and compared, in order to assess postural orientation and stabilisation processes. RESULTS Although no effect was seen in terms of orientation, our data showed that use of a lumbar brace led to a notable reduction in CP displacement along the mediolateral and anteroposterior axes. Lordosis barely affected postural performance and only an increase in the mean CP velocity was observed. Lastly, an analysis of variance failed to reveal an interaction between the "lordosis" and "brace" factors. CONCLUSION A lumbar brace (in the absence or presence of lordosis) helps subjects to improve their sitting performance. In contrast to previous studies based on the standing posture, the fact that significant differences were found as a function of brace wear emphasises the discriminant power of the sitting position. This task should therefore be applied more widely in the development of more appropriate, validated equipment for lower back pain sufferers.