Effect of Variations in Forced Expiration Effort on Pelvic Floor Activation in Asymptomatic Women. Kitani LJ, Apte GG, Dedrick GS, Sizer PS, Brismee JM. J Womens Health Phys Ther 2014. Vol38;Num1.

Michelle Spicka, DPT

June 4^th  Pelvic Physical Therapy Distance Journal Club

Objective: The purpose of this study was to investigate the effect of variations in forced expiration effort on the automatic activation of pelvic floor muscles.  The investigators were interested in gaining normative data for PF squeeze pressure and displacement in response to a standardized variation in forced expiration effort so an asymptomatic population was utilized.  It is known that forced expiration facilitates PF activation but it is unknown how the PF automatically responds to gradations of forced expirations.  Despite the importance of appropriate PF activity before and during times of forced expiration, few authors have discussed respiration concepts and methods in a clinic PF rehab program.

Methods: 26 young, nulliparous, premenopausal women (aged 18-35).

A breathing device was used to create forced expiration.  The device was modified by interchangeable tubes of differing length that provided 3 variations in resistance at a constant flow rate.

Participants practiced forced expiration until they were able to perform a sustained maximum forced expiration effort for 5 seconds 3 times in a row.  The mean of the 3 trials was used for each participant’s maximum forced expiration effort. 

Minimum and moderate efforts were then calculated at 33% and 66% of the maximum effort.

The squeeze pressure of the pelvic floor was measured using a perineometer with a silicone vaginal sensor probe.

Pelvic floor position was measured via ultrasound.

Participants were instructed to exhale at their maximum, moderate and minimum forced expiration efforts in a randomized order (3 trials of each) and no instruction was given on whether to relax or squeeze the pelvic floor during forced expiration. 

Data analysis:

The following descriptive statistics were measured for each participant: 1) age 2) BMI 3) maximum expiration effort 4) vaginal squeeze pressure during PF maximal voluntary contraction 5) vaginal squeeze pressures during the 3 variations in forced expiration effort 6) direction of PF displacement during PF MVC 7) magnitude of PF displacement during PF MVC and the 3 variations of forced expiration effort

Results:

·         A cranial-ventral PF displacement was observed most often during minimum forced expiration effort

o   Supports the use of minimum forced expiration effort during PF training programs aimed at enhancing PF displacement in an optimal and protective direction. 

·         A minimal increase in intra-abdominal pressure was noted during isolated PF and abdominal contractions whereas forced expiration produced an increase in IAP.

·         Maximum forced expiration effort predominantly led to a caudal-dorsal displacement whereas minimum forced expiration effort predominantly resulted in a cranial-ventral PF displacement

o   At minimum forced expiration effort, participants were most likely to demonstrate an automatic PF muscle activation that may have resisted the effort of forced expiration, leading to PF displacement in the ventral, cranial and cranial-ventral directions. 

·         Significant increases in vaginal squeeze pressure was noted as effort of forced expiration increased. 

o   Intravaginal pressure measurements can be affected by increases in IAP

Discussion:

·         Despite the importance of appropriate PF muscle activity before and during times of forced expiration, few authors have discussed respiration concepts and methods in a clinical PF rehabilitation program.

·         A simulated forced expiratory pattern at minimal effort facilitates an automatic squeezing contraction with a cranial-ventral displacement of the pelvic floor

o   Clinicians can use this facilitation to achieve the appropriate PF squeeze with cranial displacement.

o   This research supports the use of minimum forced expiration effort during PF training programs aimed at enhancing PF displacement in an optimal and protective direction. 

§  The use of this strategy should be evaluated using PF palpation or US as 45% of the participants did not display good technique initially

·          Because many of the participants in the study depressed the PF in a caudal-dorsal direction, especially during maximum and moderate forced expiration efforts, there is an assumption of significantly increased intra-abdominal pressure.

·         Individuals will improve PF strength and timing strategies during times of functional forced expiration when they most need effective control for continence.

o   Based on the results of this study, a simulated forced expiratory pattern at minimal effort facilitates an automatic squeezing contraction with a cranial-ventral displacement of the PF.

§  Clinicians can used this facilitation to achieve the appropriate PF squeeze with cranial displacement

Concerns about this article:

1)      45% of the women tested could not perform a pelvic floor contraction correctly. So it this representing a normal model?

2)      No allowance for previous pregnancy/abdominal pathology in these “normative” data collections.

3)      The authors made broad assumptions that their findings would correlate to a clinical treatment program but yet they tested for normative data, not the training response of the use of breathing to facilitate a pelvic floor contraction.

4)      Pressure measurements during the Valsalva by the perineometer  could actually be recording intra abdominal pressure more than pelvic floor muscle activity.

Additional Resource

1)      Literature consistently reports that conservative SUI management should emphasize patient education that focuses on methods for increasing PF muscle strength, timing and endurance during functional forced expiration such as coughing, sneezing and laughing when urine leakage occurs.  (Int Urogynecol J 2010; Int Urogynecol J Pelvic Floor Dysfunct 2002; Man Ther 2004)

2)      Inefficient breathing results in muscular imbalance, motor control alterations and physiological adaptions that are capable of modifying movement (Int J Sports Phys Ther. Feb 2014)

3)      Suboptimal breathing patterns and impairments of posture and trunk stability are associated with musculoskeletal dysfunction (North Am J of Sports Phys Ther 2010)

4)      Talasz et al (Int Urogynecol J 2011) found that in healthy women, real time dynamic MRI demonstrates parallel cranio-caudal movement of the diaphragm and the PF during breathing and coughing and synchronous changes in abdominal wall diameter

5)      Talasz et al (Int Urogynecol J 2010) observed a correlation between PFM contraction strength and forced expiratory flows…the investigators used palpation and spirometry to complete the study.