Abstract
Objective
To investigate the agreement between lower limb volume measurements for the vertically oriented perometer and a tape measure method.
Design
Between-methods agreement and test–retest reliability study.
Setting
University setting.
Participants
Thirty university staff and students were recruited using convenience sampling with no participant drop-outs.
Interventions
All participants’ dominant lower limb volumes were measured using the vertically oriented perometer and a tape measure method.
Main outcome measures
The Bland–Altman difference plot was reported for determining the bias between the two methods and its 95% confidence interval. Test–retest reliability and the measurement error for the perometer method were determined using the ICC(2,1) model and within-subject standard deviation (sw) respectively.
Results
There was a lack of agreement between the tape measure and perometer method. The Bland–Altman difference plot showed that the tape measure method overestimated limb volume by 157
ml compared to the perometer method. A 95% confidence interval of −834ml to 519ml was observed. The test–retest reliability of the perometer method was ICC(2,1)=0.99. The measurement error of the perometer method was clinically acceptable (sw=121ml).
Conclusions
There was a lack of agreement between the two methods investigated. Therefore the perometer and tape measure methods are not interchangeable. It is recommended that future validity and reliability studies for the vertically oriented perometer are conducted on clinical populations.
Abbreviations: ICC, intraclass correlation, sw, within subject standard deviation (measurement error), CV, coefficient of variation
Citation
Measurement of lower limb volume: Agreement between the vertically oriented perometer and a tape measure method. Physiotherapy - September 2013 (Vol. 99, Issue 3, Pages 247-251, DOI: 10.1016/j.physio.2012.12.004)