An Approach to Assessment of Female Urinary Incontinence Risk Using the Thickness of the Transverse Abdominal Muscle

Lateral abdominal muscle thickness and contractile function in women with and without stress urinary incontinence

INTRODUCTION AND HYPOTHESIS

Stress urinary incontinence (SUI) primarily results from the weakness of pelvic floor muscles, working synergistically with the abdominal muscles. The current study aimed to compare thickness and contractile function of lateral abdominal muscles in women with and without SUI.

METHODS

Thirty-nine women with SUI (SUI group; age: 38.87 ± 8.96 years, body mass index (BMI): 24.03 (5.94) kg/m2) and 42 healthy women (control group; age: 36.21 ± 11.46 years, BMI: 23.90 (5.85) kg/m2) were included. Transverse abdominis (TrA) and internal oblique (IO) muscle thickness at rest and during abdominal drawing-in maneuver (ADIM) were measured with ultrasound imaging in B-mode using a Logiq S7/Expert device and a 9-11 MHz linear transducer. Percentage change in thickness and contractile function of these muscles were also calculated.

RESULTS

No significant differences in the thickness of TrA and IO muscles at rest and during ADIM between the groups were found (p > 0.05). The percent change in thickness and contractile function of both right and left side TrA muscles and the right side IO muscle were lower in SUI group than control group (p < 0.05). The percentage change in thickness and the contractile function of the left side IO muscle did not change (p > 0.05).

CONCLUSION

Women with SUI had a smaller percentage change in thickness and contractile function of TrA and IO muscle than women without SUI. However, there was no difference in the morphological features of these muscles between the groups. Considering the lateral abdominal muscle, training may be important for management of SUI.

Lateral abdominal muscle thickness during breathing maneuvers in women with and without stress urinary incontinence

INTRODUCTION AND HYPOTHESIS

Stress urinary incontinence (SUI) patients predominantly experience involuntary leakage during respiratory functions that induce a rapid increase in intra-abdominal pressure (IAP) such as coughing and sneezing. The abdominal muscles have an important role in the forced expiration and modulation of IAP. We hypothesized that SUI patients have different thickness changes in the abdominal muscles compared to healthy individuals during breathing maneuvers.

METHODS

This case-control study was conducted on 17 adult women with SUI and 20 continent women. Muscle thickness changes were measured by ultrasonography at the end of deep inspiration and expiration, and the expiratory phase of voluntary coughing for external oblique (EO), internal oblique (IO), and transverse abdominis (TrA) muscles. The percent thickness changes of muscles were used and analyzed with a two-way mixed ANOVA test and post-hoc pairwise comparison at a confidence level of 95% (p < 0.05).

RESULTS

The percent thickness changes of TrA muscle were significantly lower in SUI patients at deep expiration (p < 0.001, Cohen's d = 2.055) and coughing (p < 0.001, Cohen's d=1.691). While, percent thickness changes for EO (p = 0.004, Cohen's d=0.996) and IO thickness (p < 0.001, Cohen's d=1.784) were greater at deep expiration and deep inspiration, respectively.

CONCLUSIONS

The percent thickness changes of abdominal muscles differed between women with and without SUI during breathing maneuvers. The present study provided information regarding the altered function of abdominal muscles during breathing maneuvers; therefore, it is important to consider the respiratory role of abdominal muscles for the rehabilitation of SUI patients.

Relationship between transversus abdominis muscle thickness and urinary incontinence in females at 2 months postpartum

[Purpose] Urinary incontinence is a frequent postpartum complication. Thus, this study aimed to examine the associations of transversus abdominis muscle thicknesses at rest and during an abdominal drawing-in maneuver with urinary incontinence in females at 2 months postpartum. [Participants and Methods] The participants included 18 females at 2 months postpartum with or without urinary incontinence, and 10 nulliparous females as controls. Transversus abdominis thickness was measured at rest and during the abdominal drawing-in maneuver using diagnostic ultrasonography. The Japanese version of the International Consultation on Incontinence Questionnaire-Short Form was used to evaluate urinary incontinence. [Results] Females at 2 months postpartum were divided into groups with and without urinary incontinence according to questionnaire scores. The muscle thickness during the abdominal drawing-in maneuver contraction was significantly lower in those with urinary incontinence than in those without urinary incontinence and controls. [Conclusion] The results showed significantly reduced transversus abdominis thickness during contraction, which suggested reduced transversus abdominis strength in females with postpartum urinary incontinence. Thus, promoting synergistic contraction of the inner unit, including the transversus abdominis, in exercise therapy may be more effective for postpartum urinary incontinence.

Lower trunk muscle activity-induced alignment and cop position during single-leg standing

[Purpose] The purpose of this study was to clarify fundamental changes induced by lower trunk muscle contraction during single-leg standing. [Subjects and Methods] Ten healthy normal males participated in this study. All subjects could accurately perform lower trunk muscle contraction-type Abdominal Expansion (AE), Abdominal Bracing (AB), and Abdominal Cave-in (AC). The alignment and position of the center of foot pressure (COP) during single-leg standing with SLR and step position after rotating the body from single-leg standing with maximum SLR were measured in each lower trunk muscle contraction type. [Results] When AC was performed during single-leg standing with SLR, the SLR angle increased, COP shifted backward, and the posterior tilt angle of the trunk and cross step distance decreased. [Conclusion] It was assumed that AC during wind-up increases the angle of lower limb elevation and decreases the posterior tilt angle of the trunk and cross step distance.

Effects of Co-contraction of Both Transverse Abdominal Muscle and Pelvic Floor Muscle Exercises for Stress Urinary Incontinence: A Randomized Controlled Trial

[Purpose] The purpose of this study was to devise a new urinary incontinence exercise using co-contraction of both the transverse abdominal muscle (TA) and pelvic floor muscle (PFM) and examine the intervention effect in middle-aged women with stress urinary incontinence (SUI). [Subjects] The subjects were fifteen women with SUI who were divided into two groups: the TA and PFM co-contraction exercise group (n=9) and the control group (n=6). [Methods] Participants in the exercise group performed TA and PFM co-contraction exercise. The thickness of the TA was measured before and after 8 weeks of exercise using ultrasound. The thickness of the TA was measured under 4 conditions: (1) at rest, (2) maximal contraction of the TA, (3) maximal contraction of the PFM, and (4) maximal co-contraction of both the TA and PFM. [Results] There were no significant differences among the results of the control group. In the exercise group, the cure rate of SUI was 88.9% after the intervention. There were significant differences in the thickness of the TA during maximal co-contraction of both the TA and PFM after the intervention. [Conclusion] The TA and PFM co-contraction exercise intervention increases the thickness of the TA and may be recommended to improve SUI in middle-aged women.