Intra- and inter-rater reliability of a modified measure of hand behind back range of motion

The aim of this reliability study was to identify the clinimetric properties, specifically intra- and inter-rater reliability, for measuring the functionally and clinically important hand behind back (combined shoulder internal rotation/adduction and elbow flexion) range of motion using a modified technique. Sixty asymptomatic participants (20 male, 40 female) aged 45.4 ± 11.7 years (mean ± SD). Hand behind back was measured as the distance from the mid-line between the posterior superior iliac spines (PSIS) to the tip of the thumb and recorded in centimetres above the PSIS (a positive measure) or below the PSIS (a negative measure). The intra- and inter-rater reliability for the measurement were excellent, with ICC (2,1) of 0.95 for intra-rater and ICC (2,2) of 0.96 for inter-rater reliability. The standard error of the measurement (SEM) and smallest real difference (SRD) values showed acceptable levels of measurement error, SEM 4.3 mm and SRD 12.8 mm for intra-rater reliability and SEM 2.6 mm and SRD 7.7 mm for inter-rater reliability. The assessment of hand-behind-back motion from a point equidistant between the PSISs to the tip of the thumb is more reliable than traditional methods and a useful clinical tool.