The impact of a familiarization session on the magnitude and stability of active and passive pelvic floor muscle forces measured through intravaginal dynamometry

Abstract

Aims The aim of this study was to investigate the impact of task familiarization on (1) the magnitude and (2) the repeatability of active and passive properties of the female pelvic floor muscles (PFMs) measured using automated intra‐vaginal dynamometry. Methods Women attended three laboratory sessions at one‐week intervals. After receiving initial task instruction and feedback at the start of the first session, standardized instructions were given while women performed maximal effort voluntary contractions of their PFMs with the dynamometer arms open at two different diameters and kept their PFMs relaxed while the dynamometer arms opened to 40 mm at two speeds. Outcomes included baseline force, peak force, relative peak forces (N), rate of force development (N/s) and stiffness. Between session effects were tested for all outcomes using one‐way ANOVAs. Intra‐class correlation coefficients (ICCs) and minimal detectable change values were computed within each session and between sessions 1 and 2 and sessions 2 and 3. Results Twenty nulliparous women (mean age = 35 ± 15 years) participated. No differences in the mean values were found across the three visits for any outcomes. Within sessions, neither ICC nor minimal detectable change differed among sessions and between‐session ICC values were not different between visits 1 and 2 and visits 2 and 3. Conclusions There is no evidence of a familiarization effect over a two‐week period on the amplitude nor repeatability of dynamometric measures of active or passive PFM properties recorded from nulliparous women.

Design and validation of an automated dual‐arm instrumented intravaginal dynamometer

“…In vivo data from the posterior arm of the novel IVD presented here were similar to those obtained using our first‐generation IVD, which acquired force data only on the posterior arm 25,30,31 . In a group of 20 nulliparous participants, during a passive stretching task performed in supine and using the same testing parameters, Bérubé et al 25 reported similar values for relative peak force (current = 12.56 ± 6.18 N, Bérubé et al 25 =14.35 ± 4.20 N, p > .05) and rate of force development (current = 33.71 ± 10.63 N/s, Bérubé et al 25 =36.89 ± 7.07 N/s, p > .05).…”

The state of pelvic floor muscle dynamometry: A scoping review

“…Only five reports in four dynamometers (two handheld, and one “stay in place”) presented inter‐rater reliability 10,17,18,55,59 . Maximal force during PFM maximal voluntary contraction was the most studied parameter ( n = 14) 7,9,10,16,17,21,37,38,46,48,54,57,59,64 . Overall results suggested moderate to strong repeatability of measurements, supporting dynamometers as a reliable instrument to assess PFM function.…”

“…Reliability studies were conducted for 13 dynamometers in 18 reports 8–11,17,18,20,22,24,25,30,37,38,54,55,57,59,64 . Most presented intra‐rater reliability either within‐visit ( n = 9) 10,11,25,30,37,54,55,57,64 or between‐visits ( n = 13) 8,9,11,17,18,20,22,24,30,37,38,59,64 . Only five reports in four dynamometers (two handheld, and one “stay in place”) presented inter‐rater reliability 10,17,18,55,59 .…”

“…25 Reliability studies were conducted for 13 dynamometers in 18 reports. [8][9][10][11]17,18,20,22,24,25,30,37,38,54,55,57,59,64 Most presented intra-rater reliability either withinvisit (n = 9) 10,11,25,30,37,54,55, 57,64 or between-visits (n = 13). 8,9,11,17,18,20,22,24,30,37,38,59,64 Only five reports in four dynamometers (two handheld, and one "stay in place") presented inter-rater reliability.…”

Absolute and Relative Reliability of the Assessment of the Muscle Mechanical Properties of Pelvic Floor Muscles in Women with and without Urinary Incontinence

“…Some of these difficulties are: the specific localization of the measurement, the stabilization of the MyotonPRO position by the rater during the repetition of the pulses for each measurement, or the variability of the relaxation state of the participants during the entire assessment procedure. Further studies with specific training programs are required to address these concerns, although previous studies have questioned the dependence of training and familiarization sessions on the stability of PFM forces [ 51 ].…”