Spine J. 2009 May 30; Dupeyron A, Lecocq J, Vautravers P, Pélissier J, Perrey SBACKGROUND CONTEXT: There is little information about the simultaneous changes of intramuscular pressure (IMP) and oxygen saturation (StO(2)) of the paraspinal muscle under various conditions of posture and load. PURPOSE: To measure simultaneously and compare IMP and StO(2) across a range of static trunk postures commonly observed during normal work tasks. STUDY DESIGN: A prospective study using a repeated-measure design in clinical setting. PATIENT SAMPLE: Sixteen healthy young men with no history of back pain. OUTCOME MEASURES: Simultaneous measurements of IMP by a flexible slit catheter and StO(2) by near infrared spectroscopy of the multifidus muscle were performed. METHODS: The two measures were taken in six static posture tasks: standing upright and bending forward with and without load (20kg), bending backward and during a sustained isometric contraction (ie, Sorensen test). To compare the influence of the tasks on IMP and StO(2) variables, a one-way variance analysis with repeated measures was used. Spearman's rank correlation coefficient (rho) was determined between the two variables for each posture task. RESULTS: We observed only a moderate but significant correlation between IMP and StO(2) values in upright standing and a trend in bending forward positions with load (p
