Test-retest intra-rater reliability of vaginal measurement of pelvic floor muscle strength using Myomed 932

Objectives. To investigate test-retest intra-rater reliability of measurements of pelvic floor muscle (PFM) strength using Myomed 932 (R) (Enraf-Nonius, Delft, the Netherlands). Design. Test-retest intra-rater reliability test with a 2-7 day interval. Setting. Physiotherapy outpatient clinic in association with the Department of Physiotherapy, University of Iceland. Population. Twenty healthy female volunteers in Reykjavik metropolitan area, Iceland, with a mean age of 43.8 (SD 9.8) years, mean body mass index (BMI) 26.2 (SD 5.3), and mean parity 2.1 children (SD 1.0). Main outcome measures. PFM strength during two attempts of maximal voluntary contraction (MVC) measured as vaginal squeeze pressure in hectoPascals (hPa). Results. Mean MVC was 34.45 hPa (95% CI: 26.07-42.83) on Day 1 and 34.05 hPa (95% CI: 26.66-41.44) on Day 2. The measurements ranged from 5-74 hPa interindividually on Day 1 and 5-62 hPa on Day 2. Intraclass Correlation Coefficient (ICC) was 0.97; p<0.001 and coefficient of variation (CV%) was 11.09%. There was no significant difference between the first and second tests (p = 0.74). Conclusion. This test-retest intra-rater reliability study for Myomed 932 showed a very good reliability using ICC. The CV%, however, indicated some degree of intra-individual variation. We suggest that this device can be used both in practice and clinical trials for assessing female PFM strength.