Stadiometry: on measurement technique to reduce variability in spine shrinkage measurement.

OBJECTIVE: To test the effect of two measurement techniques for repeated measures of spine height using stadiometry following five experimental activity conditions.DESIGN. Six subjects were repeatedly measured while they stepped in and out of the stadiometer for each pair of measures and again on another day when they remained in place in the stadiometer for all 10 measures.RESULTS. There was much greater variability in height measures with the "in-out" method while the "in place" method demonstrated a steady shrinkage over the 3-3.5 min required to obtain the repeated measures. RelevanceContrary to popular practice, leaving a subject in the stadiometer during repeated measures includes the shrinkage that occurs over the 3-3.5 min of measurement when standing and reduces random variation due to posture change.