Intra-rater reliability of rectus abdominis diastasis measurement using dial calipers

To date, physiotherapists have relied upon the use of finger widths for measurement of rectus abdominis diastasis (RAD). This method has been proven unreliable, due to variations in finger widths. The intra-rater reliability of dial calipers for measurement of RAD was investigated by this study, using a repeated measures design. Measurements were taken at rest and during contraction on three occasions in 30 postpartum subjects. High reliability was demonstrated for resting and active RAD measurements, (ICC=0.93 and 0.95 respectively). In conclusion, dial calipers are a reliable measuring device when used by a single clinician. Further testing is required to determine inter-rater reliability.