title: Muscular fatigue in the pelvic floor muscles after strenuous physical activity.
abstract: BACKGROUND
  It is not clear why young nulliparous women may leak urine during exercise. The aim of this study was to investigate whether strenuous physical activity can produce pelvic floor muscle fatigue.
  
  
  METHODS
  Participants in this crossover study included 12 nulliparous women with mild symptoms of stress urinary incontinence during strenuous physical activity. Participants were randomized to start with either the intervention (a 90-min interval training program) or the control period (rest in sitting position for 90 min). Maximal voluntary contraction pressure (cm H(2)O), vaginal resting pressure (cm H(2)O), and holding time (s) were measured before and after intervention and rest by a fiberoptic microtip transducer connected to a balloon catheter inserted into the vagina.
  
  
  RESULTS
  Mean age of the group was 24 years (+/-1.7). The mean maximal voluntary contraction pressure decreased 20% (+/-24.4) after physical activity. The mean difference in maximal voluntary contraction pressure was significantly larger after physical activity than after rest (-4.4 versus 0.6 cm H(2)O difference, respectively, p<0.01). There were no statistically significant differences in resting pressure or holding time.
  
  
  CONCLUSIONS
  In young nulliparous women with symptoms of mild stress urinary incontinence, strenuous physical exercise results in lower maximal voluntary vaginal contraction pressure, indicating pelvic floor muscle fatigue. Further research is needed to understand the long-term impact of this finding.
authors.affiliation: St. Olavs Hospital, Clinical Service, Olav Kyrres gate 17, 7006 Trondheim, Norway. marit.lindland@bntv.no
authors.forename: Marit Lindland
authors.initials: ML
authors.lastname: Ree
authors.forename: Ingrid
authors.initials: I
authors.lastname: Nygaard
authors.forename: Kari
authors.initials: K
authors.lastname: Bø
mesh_terms: D000328:Adult; D018592:Cross-Over Studies; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D009119:Muscle Contraction / Q000502:physiology; D018763:Muscle Fatigue / Q000502:physiology*; D009130:Muscle, Smooth / Q000502:physiology*; D017773:Pelvic Floor / Q000502:physiology; D014550:Urinary Incontinence, Stress / Q000209:etiology