Objectives To present a new water displacement measurement, the Simplified Water Displacement Instrument (SWDI), and to evaluate its intra- and intertester reliability. Design Reliability design. Setting Hospital setting. Participants Fifty-six healthy people were studied. Intratester reliability was evaluated once a week for 4 weeks in 20 women and 10 men. Intertester reliability was assessed by 2 physical therapists in 26 people. Interventions Not applicable. Main outcome measures Coefficients of variation (CVs) and intraclass correlation coefficients (ICCs). Results The intratester reliability showed a CV range of 2.2% to 2.6% and an ICC range of .98 to .99. The intertester reliability showed a CV of 1.3% and an ICC of .99. There was a significant increase in arm volume in men compared with women. There were no significant differences in changes in volume over the 4 weeks. There was a significant greater right arm volume (3.3%) among the right-handed subjects (P<.001). Conclusions Both intra- and intertester reliability were satisfactory for the SWDI. © 2005 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation.
Sagen, Å., Kåresen, R., & Risberg, M. A. (2005). The reliability of a simplified water displacement instrument: A method for measuring arm volume. Archives of Physical Medicine and Rehabilitation, 86(1), 86–89. https://doi.org/10.1016/j.apmr.2003.12.042