Objectives: 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.
Design: Prospective study.
Setting: Academic laboratory.
Participants: Convenience sample of 63 unimpaired volunteers (mean age +/- standard deviation, 25.95+/-5.75 y).
Interventions: Not applicable.
Main outcome measures: 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.
Results: 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.
Conclusion: 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.