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Women with SUI demonstrate motor control differences during voluntary pelvic floor muscle contractions


Introduction and hypothesis

To compare maximum abdominal and pelvic floor muscle (PFM) electromyographic (EMG) and intravaginal pressure (IVP) amplitudes and muscle activation patterns during voluntary PFM contractions between women with and without stress urinary incontinence (SUI).


Twenty-eight continent women and 44 women with SUI performed single and repeated PFM contractions in supine. Surface EMG data were recorded simultaneously with IVP. Maximum EMG and IVP amplitudes and ensemble average IVP versus EMG curves were determined from the single contractions. Muscle activation timing was determined with cross-correlation functions from the repeated contractions.


The continent group produced higher PFM EMG amplitudes than the SUI group; there were no between group differences in IVP. The women with SUI delayed activating rectus abdominus. The IVP versus EMG curves’ shapes were similar between the groups, however the SUI group had higher abdominal muscle y-intercepts than the continent women.


These findings suggest that women with SUI demonstrate altered motor control strategies during voluntary PFM contractions.

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analog to digital


analysis of variance


body mass index


confidence interval


electromyography or electromyographic


external obliques muscle


internal obliques muscle


intravaginal pressure


maximum voluntary contraction


maximum voluntary electrical activity


pelvic floor muscle


rectus abdominis muscle


root mean square


stress urinary incontinence


  1. 1.

    Vereecken RL, Verduyn H (1970) The electrical activity of the paraurethral and perineal muscles in normal and pathological conditions. Br J Urol 42:457–463

    PubMed  Article  CAS  Google Scholar 

  2. 2.

    Shafik A, Doss S, Asaad S (2003) Etiology of the resting myoelectric activity of the levator ani muscle: physioanatomic study with a new theory. World J Surg 27:309–314

    PubMed  Article  Google Scholar 

  3. 3.

    Deindl FM, Vodusek DB, Hesse U, Schussler B (1993) Activity patterns of pubococcygeal muscles in nulliparous continent women. Br J Urol 72:46–51

    PubMed  Article  CAS  Google Scholar 

  4. 4.

    Abrams P, Cardozo L, Khoury S, Wein A (eds) (2002) Incontinence. 2nd International Consultation on Incontinence. Health Publications Ltd., Paris

  5. 5.

    Bø K, Sherburn M (2005) Evaluation of female pelvic-floor muscle function and strength. Phys Ther 85:269–282

    PubMed  Google Scholar 

  6. 6.

    Gunnarsson M, Mattiasson A (1999) Female stress, urge, and mixed urinary incontinence are associated with a chronic and progressive pelvic floor/vaginal neuromuscular disorder: an investigation of 317 healthy and incontinent women using vaginal surface electromyography. Neurourol Urodyn 18:613–621

    PubMed  Article  CAS  Google Scholar 

  7. 7.

    Sørensen S (1989) Urethral pressures during bladder filling. Scand. J Urol Nephrol Suppl 125:45–51

    PubMed  Google Scholar 

  8. 8.

    Morin M, Bourbonnais D, Gravel D, Dumoulin C, Lemieux MC (2004) Pelvic floor muscle function in continent and stress urinary incontinent women using dynamometric measurements. Neurourol Urodyn 23:668–674

    PubMed  Article  Google Scholar 

  9. 9.

    Bø K (2004) Pelvic floor muscle training is effective in treatment of female stress urinary incontinence, but how does it work? Int Urogynecol J 15:76–84

    Article  Google Scholar 

  10. 10.

    Smith MD, Coppieters MW, Hodges PW (2007) Postural response of the pelvic floor and abdominal muscles in women with and without incontinence. Neurourol Urodyn 26:377–385

    PubMed  Article  Google Scholar 

  11. 11.

    DeLancey JOL (1996) Stress urinary incontinence: where are we now, where should we go? Am J Obstet Gynecol 175:311–319

    PubMed  Article  CAS  Google Scholar 

  12. 12.

    Thompson JA, O'Sullivan PB, Briffa NK, Neumann P (2006) Differences in muscle activation patterns during pelvic floor muscle contraction and valsalva manouevre. Neurourol Urodyn 25:148–155

    PubMed  Article  Google Scholar 

  13. 13.

    Neumann P, Gill V (2002) Pelvic floor and abdominal muscle interaction: EMG activity and intra-abdominal pressure. Int Urogynecol J 13:125–132

    Article  CAS  Google Scholar 

  14. 14.

    Amarenco G, Ismael SS, Lagauche D, Raibaut P, Rene-Corail P, Wolff P et al (2005) Cough anal reflex: strict relationship between intravesical pressure and pelvic floor muscle electromyographic activity during cough. Urodynamic and electrophysiological study. J Urol 173:149–152

    PubMed  Google Scholar 

  15. 15.

    Bø K, Stien R (1994) Needle EMG registration of striated urethral wall and pelvic floor muscle activity patterns during cough, valsalva, abdominal, hip adductor, and gluteal muscle contractions in nulliparous healthy females. Neurourol Urodyn 13:35–41

    PubMed  Article  Google Scholar 

  16. 16.

    Devreese A, Staes F, De Weerdt W, Feys H, Van Assche A, Penninckx F et al (2004) Clinical evaluation of pelvic floor muscle function in continent and incontinent women. Neurourol Urodyn 23:190–197

    PubMed  Article  Google Scholar 

  17. 17.

    Madill SJ, McLean L (2007) Quantification of abdominal and pelvic floor muscle synergies in response to voluntary pelvic floor muscle contractions. Journal doi:10.1016/j.jelekin.2007.05.001

  18. 18.

    Madill SJ, McLean L (2006) Relationship between abdominal and pelvic floor muscle activation and intravaginal pressure during pelvic floor muscle contractions in healthy continent women. Neurourol Urodyn 25:722–730

    PubMed  Article  Google Scholar 

  19. 19.

    Al-Taher H, Sutherst JR, Richmond DH, Brown MC (1986) Vaginal pressure as an index of intra-abdominal pressure during urodynamic evaluation. Br J Urol 59:529–532

    Article  Google Scholar 

  20. 20.

    Bø K (1992) Pressure measurements during pelvic floor muscle contractions: the effect of different positions of the vaginal measuring device. Neurourol Urodyn 11:107–113

    Article  Google Scholar 

  21. 21.

    Madill SJ, McLean L. (2004) Electromyographic crosstalk in the measurement of pelvic floor muscle activation. 15th ISEK Congress, Boston, MA, USA

  22. 22.

    Madill SJ, Harvey M-A, McLean L. (2006) A biomechanical model of intravaginal pressure generation comparing continent and stress incontinent women. 16th ISEK Congress, Turin, Italy

  23. 23.

    Ingelman-Sundberg A (1953) Urininkontinens hos kvinnan. Nordisk Medicin 20:1149–1152

    Google Scholar 

  24. 24.

    DeLancey JOL, Kearney R, Chou Q, Speights S, Binno S (2003) The appearance of levator ani muscle abnormalities in magnetic resonance images after vaginal delivery. Obstet Gynecol 101:46–53

    PubMed  Article  Google Scholar 

  25. 25.

    Winter DA (2005) Biomechanics and Motor Control of Human Movement, Third Edition. Wiley, Hoboken

    Google Scholar 

  26. 26.

    Miller JM, Ashton-Miller JA, DeLancey JOL (1998) A pelvic muscle precontraction can reduce cough-related urine loss in selected women with mild SUI. J Am Geriatr Soc 46:870–874

    PubMed  CAS  Google Scholar 

  27. 27.

    Verelst M, Leivseth G (2004) Are fatigue and disturbances in pre-programmed activity of pelvic floor muscles associated with female stress urinary incontinence? Neurourol Urodyn 23:143–147

    PubMed  Article  CAS  Google Scholar 

  28. 28.

    Barbic M, Kralj B, Cor A (2003) Compliance of the bladder neck supporting structures: importance of activity pattern of levator ani muscle and content of elastic fibers of endopelvic fascia. Neurourol Urodyn 22:269–276

    PubMed  Article  Google Scholar 

  29. 29.

    Smith MD, Coppieters MW, Hodges PW (2007) Postural activity of the pelvic floor muscles is delayed during rapid arm movements in women with stress urinary incontinence. Int Urogynecol J 18:901–911

    Article  Google Scholar 

  30. 30.

    Andrews A, McLean L. (2007) Performance of onset detection methods for sEMG. 30th CMBES Conference, Toronto, Ontario, Canada

  31. 31.

    Hodges P, Richardson C (1996) Inefficient muscular stabilization of the lumbar spine associated with low back pain: a motor control evaluation of transversus abdominis. Spine 21:2640–2650

    PubMed  Article  CAS  Google Scholar 

  32. 32.

    Aukee P, Penttinen J, Airaksinen O (2003) The effect of aging on the electromyographic activity of pelvic floor muscles. A comparative study among stress incontinent patients and asymptomatic women. Maturitas 44:253–257

    PubMed  Article  Google Scholar 

  33. 33.

    Frawley HC, Galea MP, Phillips BA, Sherburn M, Bø K (2006) Reliability of pelvic floor muscle strength assessment using different test positions and tools. Neurourol Urodyn 25:236–242

    PubMed  Article  Google Scholar 

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Financial support for this work was provided by Physicians’ Services Inc. Foundation of Ontario, Canada and the Physiotherapy Foundation of Canada. Infrastructure support was provided by the Canadian Foundation for Innovation and the Ontario Innovation Trust. The authors wish to thank Cindy Brown B.Sc.(PT), M.Sc., Lorraine Chick RN(EC), M.Sc.N., Fabiola Gonçalves B.Sc.(PT), M.Sc., and Roy Young CBET for their assistance with technical support, data collection, and volunteer screening.

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Correspondence to Linda McLean.

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Madill, S.J., Harvey, MA. & McLean, L. Women with SUI demonstrate motor control differences during voluntary pelvic floor muscle contractions. Int Urogynecol J 20, 447–459 (2009).

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  • Electromyography
  • Intravaginal pressure
  • Motor control
  • Pelvic floor muscles
  • Stress urinary incontinence