A NEW APPARATUS FOR TRIAXIAL MEASUREMENT OF LUMBAR MOMENTS IN ISOMETRIC MODE

Quantification of the functional capacity of the human lumbar muscles has been of interest during the past decades. Until now several apparatuses have been designed to fulfill this need. One of the most widely used triaxial apparatus in this field has been Isostation B200, from Isotechnologies Ltd., which was produced in 1980’s. The most important problem with this apparatus is the cross-talk among its joint torques and the subsequent error in complex postures. In this paper, a new apparatus is introduced. The main features of the new apparatus are: 1-simultaneous measurement of the three lumbar moments, 2-relatively accurate measurement due to absence of cross-talk among joint torque data, 3-ability to accommodate the subject in any combination of the three anatomical trunk angles, 4-ability to operate in two different working modes, i.e. strength testing and tracking. In the strength testing mode, the maximum moments of the subject are measured, while in the tracking mode the subject is asked to exert moments to comply with the moment profile shown on the screen. The tracking mode is a novel measurement method which may be used for evaluation of the neuromuscular performance of the lumbar spine.