title: Differences in muscle activation patterns during pelvic floor muscle contraction and Valsalva maneuver.
abstract: OBJECTIVE
  To investigate the different muscle activation patterns around the abdomino-pelvic cavity in continent women and their effect on pressure generation during a correct pelvic floor muscle (PFM) contraction and a Valsalva maneuver.
  
  
  METHODS
  Thirteen continent women were assessed. Abdominal, chest wall, and PFM activity and vaginal and intra-abdominal pressure (IAP), were recorded during two tasks: PFM contraction and Valsalva whilst bladder base position was monitored on trans-abdominal ultrasound. A correct PFM contraction was defined as one that resulted in bladder base elevation and a Valsalva resulted in bladder base depression.
  
  
  RESULTS
  Comparison of the mean of the normalized EMG activity of all the individual muscle groups was significantly different between PFM contraction and Valsalva (P = 0.04). During a correct PFM contraction, the PFM were more active than during Valsalva (P = 0.001). During Valsalva, all the abdominal muscles (IO (P = 0.006), EO (P < 0.001), RA (P = 0.011)), and the chest wall (P < 0.001) were more active than during PFM contraction. The change in IAP was greater during Valsalva (P = 0.001) but there was no difference in the change in vaginal pressure between PFM contraction and Valsalva (P = 0.971).
  
  
  CONCLUSIONS
  This study demonstrates a difference in muscle activation patterns between a correct PFM contraction and Valsalva maneuver. It is important to include assessment of the abdominal wall, chest wall, and respiration in the clinical evaluation of women performing PFM exercises as abdominal wall bracing combined with an increase in chest wall activity may cause rises in IAP and PFM descent.
authors.affiliation: School of Physiotherapy, Curtin University of Technology, Perth, Western Australia. judiththompson@bigpond.com
authors.forename: Judith A
authors.initials: JA
authors.lastname: Thompson
authors.forename: Peter B
authors.initials: PB
authors.lastname: O'Sullivan
authors.forename: N Kathryn
authors.initials: NK
authors.lastname: Briffa
authors.forename: Patricia
authors.initials: P
authors.lastname: Neumann
mesh_terms: D034861:Abdominal Wall / Q000000981:diagnostic imaging / Q000502:physiology; D000328:Adult; D004576:Electromyography; D005260:Female; D006801:Humans; D008875:Middle Aged; D009130:Muscle, Smooth / Q000502:physiology*; D017773:Pelvic Floor / Q000502:physiology*; D014463:Ultrasonography; D014621:Vagina / Q000502:physiology; D014636:Valsalva Maneuver / Q000502:physiology*