Strapped versus unstrapped technique of the prone press-up for measurement of lumbar extension using a tape measure: differences in magnitude and reliability of measurements.

Abstract

To determine (1) the reliability of the prone press-up to measure lumbar extension using a strap and not using a strap to control pelvic movement in experienced clinicians and students and (2) if a difference exists between the magnitude of lumbar extension range of motion between the strapped and unstrapped condition. Prospective study. Academic laboratory. Convenience sample of 63 unimpaired volunteers (mean age +/- standard deviation, 25.95+/-5.75 y). Not applicable. Lumbar extension was measured in the prone position by using a tape measure to measure the perpendicular distance of the sternal notch to the support surface while using a strap and not using a strap to control pelvic movement. All measurements were performed independently by 2 groups of examiners (1 experienced group, 1 student group) and repeated to determine intrarater and interrater reliabilities. Intrarater and interrater reliability were good or excellent for all methods and all measurement group comparisons (intraclass correlation coefficient range, .82-.91). Additionally, the amount of lumbar extension, as measured by the prone press-up, during the strapped condition was significantly greater than with the unstrapped condition. Use of a tape measure while the subject performs a prone press-up appears to be a reliable method for the measurement of lumbar extension. This technique is reliable whether the examiner is experienced or inexperienced and whether or not the subject has the pelvis secured with a strap.