Using Transabdominal Ultrasound to Assess Pelvic Floor Muscle Activation

Have you ever tried to teach a patient how to isolate their transversus abdominis (TA) contraction or a pelvic floor muscle (PFM) contraction and the patient had difficulty or you weren’t sure how well they were isolating it? Did you ever wish you had the ability to use real-time ultrasound (US) to confirm which abdominal layers they were isolating or use it for visual feedback to assist in your patient’s learning?  Could it be helpful to be able to use real-time US to identify if they were isolating the pelvic floor muscles and give your patient visual feedback? Of course!

Real- time US has been used as an assessment and teaching tool to directly visualize abdominal and PFMs.  PFM function can be assessed by observing movement at the bladder base and bladder neck.  Various studies have used US on women with and without urinary incontinence (UI).  These studies usually use transabdominal (TAUS) and transperineal (TPUS) ultrasound to measure if PFM isometrics or exercises are performed correctly or incorrectly, or how the muscles are functioning.

A 2015 study in the International Urogynecology Journal utilized TAUS to identify the ability to perform a correct elevating PFM contraction and assess bladder base movement during an abdominal curl up exercise. Abdominal curl ups are cited to increase intra-abdominal pressure.  Activities that increase intra-abdominal pressure have been cited to provoke stress urinary incontinence (SUI). Abdominal curl ups are often completed in group exercise classes and have been found to provoke SUI in up to 16% of women.

Use of PFM exercises and of “the knack” (performing an isometric pelvic contraction before an exertional activity where intra-abdominal pressure increases, such as before lifting or coughing) has been shown to help manage stress urinary incontinence.

The theory is that elevation of the PFMs during activities that increase intraabdominal pressure (like a curl up) assist in urethral closure and counter act the downward movement, therefore stabilizing the urethra and bladder neck. When using TAUS, while performing a correct PFM contraction, one might expect to see an elevating PFM contraction.  In the study, TAUS was used on 90 women participating in a variety of group exercise classes.  The participants completed a survey and then three attempts of an abdominal curl up exercise in hooklying.  During the curl ups, bladder base displacement was measured to determine correct or incorrect activation patterns.  It was found that 25% of the women were unable to demonstrate an elevating PFM contraction, and all women displayed bladder base depression on the abdominal curl exercise.  It was also found that parous women displayed more bladder base depression than nulliparous women, and overall 60% of the participants reported SUI.  Lastly, this study found there was no association between SUI and the inability to perform an elevating PFM contraction or the amount of bladder base depression.

What interesting information.  Using real time US in the clinic could help us identify if our patients were completing “the knack” correctly with specific activities. This study is a great example of how we can use real time US to help collect evidence to provide us with more information that can help us answer our own questions, patient questions, and improve our instructional methods to patients when teaching core or PFM exercises.

1) Barton, A., Serrao, C., Thompson, J., & Briffa, K. (2015). Transabdominal ultrasound to assess pelvic floor muscle performance during abdominal curl in exercising women. International urogynecology journal, 26(12), 1789-1795.