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The reliability of a simplified water displacement instrument: a method for measuring arm volume
Ase Sagen1, Rolf Kåresen, May Arna Risberg
1Ulevaal University Hospital, Oslo, Norway. aase.sagen@ulleval.no
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.
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