Differences in muscle activation patterns during pelvic floor muscle contraction and Valsalva maneuver

AIMS: 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.     

Pelvic floor muscle exercise for the treatment of female stress urinary incontinence: II. Validity of vaginal pressure measurements of pelvic floor muscle strength and the necessity of supplementary methods for control of correct contraction

The present investigation comprises three methodological studies concerning vaginal pressure measurements of pelvic floor muscle (PFM) strength. Vaginal pressure was measured by a balloon (6.7 ± 1.7 cm) connected by a catheter to a pressure transducer. The balloon was placed with the middle of the balloon 3.5 cm inside the introitus vagina. In fourty-seven women, mean age 44.9 years (24–64), observation of movement of the vaginal catheter during PFM contraction verified 7 inconclusive results from perineovaginal palpation and was the most valid way to distinguish between correct and incorrect PFM contraction. Vaginal pressure rise was obtained regardless of correct or incorrect PFM contraction, showing that vaginal pressure is not specific for PFM contraction. However, as the action of the PFM is elevation, a simultaneous inward movement of the vaginal catheter is present only during correct PFM contraction. Degree of influence of various muscle groups on vaginal pressure was investigated in 14 women using two different balloons, one having a silicone reinforcement of the tip. It was found that the median contraction value of muscles other than the PFM did not exceed contraction of PFM alone. No significant difference was observed using the two types of balloons. In three physical therapists EMG activity of the lower m. rectus abdominis was recorded during maximal PFM contractions. A rise in EMG activity always occurred during maximal contractions even if the women actively tried to relax the abdominal muscles. It is concluded that vaginal pressure measurement of PFM strength is valid with simultaneous observation of inward movement of the balloon catheter. Vaginal pressure rise due to simultaneous contraction of other muscles is probably not larger than pressure rise due to intended PFM contraction. Reinforced balloon tip will not change pressure recording, and rise in EMG activity of lower abdominal muscles seems unavoidable during maximal PFM contraction.     

Relationship between abdominal and pelvic floor muscle activation and intravaginal pressure during pelvic floor muscle contractions in healthy continent women

AIM: Activation of the abdominal muscles might contribute to the generation of a strong pelvic floor muscle contraction, and consequently may contribute to the continence mechanism in women. The purpose of this study was to determine the abdominal muscle activation levels and the patterns of muscle activity associated with voluntary pelvic floor muscle (PFM) contractions in urinary continent women. METHODS: Fifteen healthy continent women participated. They performed three maximal contractions of each of the four abdominal muscles and of their PFMs while in supine. Abdominal and PFM activity was recorded using electromyography (EMG), and intravaginal pressure was recorded using a custom modified Femiscan probe. RESULTS: During voluntary maximal PFM contractions, rectus abdominus was activated to 9.61 (+/-7.42)% maximal voluntary electrical activity (MVE), transversus abdominus was activated to 224.30(+/-47.4)% MVE, the external obliques were activated to 18.72(+/-13.33)% MVE, and the internal obliques were activated to 81.47(+/-63.57)% MVE. A clear pattern of activation emerged, whereby the transversus abdominus, internal oblique, and rectus abdominus muscles worked with the PFM in the initial generation of maximal intravaginal pressure. PFM activity predominated in the initial rise in lower vaginal pressure, with later increases in pressure (up to 70% maximum pressure) being associated with the combined activation of the PFM, rectus abdominus, internal obliques, and transverses abdominus. These abdominal muscles were the primary source of intravaginal pressure increases in the latter 30% of the task, whereas there was little increase in PFM activation from this point on. The external oblique muscles showed no clear pattern of activity, but worked at approximately 20% MVE throughout the PFM contractions, suggesting that their role may be predominantly in postural setting prior to the initiation of intravaginal pressure increases. CONCLUSIONS: Defined patterns of abdominal muscle activity were found in response to voluntary PFM contractions in healthy continent women.     

Pelvic floor muscle strength and thickness in continent and incontinent nulliparous pregnant women

The aim of the study was to measure pelvic floor muscle function in continent and incontinent nulliparous pregnant women. The study group consisted of 103 nulliparous pregnant women at 20 weeks of pregnancy. Women reporting urinary incontinence once per week or more during the previous month were classified as incontinent. Function was measured by vaginal squeeze pressure (muscle strength) and increment in thickness of the superficial pelvic floor muscles (urogenital diaphragm) assessed by perineal ultrasound. Seventy-one women were classified as continent and 32 women as incontinent. Continent women had statistically significantly higher maximal vaginal squeeze pressure and increment in muscle thickness when compared with incontinent women. There was a strong correlation between measurements of vaginal squeeze pressure and perineal ultrasound measurements of increment in muscle thickness. This study demonstrates statistically significant differences in pelvic floor muscle function measured by strength and thickness in continent compared with incontinent nulliparous pregnant women. Editorial Comment: This study evaluated pelvic floor muscle function in 103 nulliparous continent and incontinent women at 18–20 weeks gestation. Pelvic floor muscle strength was assessed by measuring vaginal squeeze pressure, and thickness of the urogenital diaphragm during both relaxation and contraction was measured using perineal ultrasound. The authors found a statistically significant higher vaginal squeeze pressure and higher mean increment in muscle thickness in the continent compared with incontinent group as well as a strong correlation between pelvic floor muscle strength and increment in thickness. Although describing several benefits of ultrasonography in assessing pelvic floor muscles, the authors did acknowledge the difficulty in identifying and measuring these muscles, and the learning curve involved with perineal ultrasound. Another limitation was the subjective classification of continence status based on self-reported symptoms. The implication of low pelvic floor muscle strength and thickness as risk factors for the development of urinary incontinence is beyond the scope of this study.     

Assessment of voluntary pelvic floor muscle contraction in continent and incontinent women using transperineal ultrasound, manual muscle testing and vaginal squeeze pressure measurements

The aims of the study were: (1) to assess women performing voluntary pelvic floor muscle (PFM) contractions, on initial instruction without biofeedback teaching, using transperineal ultrasound, manual muscle testing, and perineometry and (2) to assess for associations between the different measurements of PFM function. Sixty continent (30 nulliparous and 30 parous) and 60 incontinent (30 stress urinary incontinence (SUI) and 30 urge urinary incontinence (UUI)) women were assessed. Bladder neck depression during attempts to perform an elevating pelvic floor muscle (PFM) contraction occurred in 17% of continent and 30% of incontinent women. The UUI group had the highest proportion of women who depressed the bladder neck (40%), although this was not statistically significant (p=0.060). The continent women were stronger on manual muscle testing (p=0.001) and perineometry (p=0.019) and had greater PFM endurance (p<0.001) than the incontinent women. There was a strong tendency for the continent women to have a greater degree of bladder neck elevation than the incontinent women (p=0.051). There was a moderate correlation between bladder neck movement during PFM contraction measured by ultrasound and PFM strength assessed by manual muscle testing (r=0.58, p=0.01) and perineometry (r=0.43, p=0.01). The observation that many women were performing PFM exercises incorrectly reinforces the need for individual PFM assessment with a skilled practitioner. The significant correlation between the measurements of bladder neck elevation during PFM contraction and PFM strength measured using MMT and perineometry supports the use of ultrasound in the assessment of PFM function; however, the correlation was only moderate and, therefore, indicates that the different measurement tools assess different aspects of PFM function. It is recommended that physiotherapists use a combination of assessment tools to evaluate the different aspects of PFM function that are important for continence. Ultrasound is useful to determine the direction of pelvic floor movement in the clinical assessment of pelvic floor muscle function in a mixed subject population.     

Evaluation of Pelvic Floor Muscle Strength Using Four Different Techniques

The aim of the study was to evaluate whether four different techniques were able to correctly measure pelvic floor muscle strength only. Sixteen volunteers performed a set of muscle contractions using the pelvic floor muscles (PFM) only, the abdominal muscles with and without PFM, gluteal muscles with and without PFM, adductor muscles with and without PFM and Valsalva maneuver with and without PFM. Pelvic floor muscle strength was evaluated by digital palpation, intravaginal EMG, pressure perineometry and perineal ultrasound. A “non-pelvic muscle induced” reading was defined as a significant increase even though the pelvic floor muscles were not contracted. Results were as follows: isolated abdominal muscle contraction: non-pelvic muscle induced readings in 3/8 women with EMG and in 3/8 with pressure perineometry; isolated gluteal muscle contraction: non-pelvic muscle induced readings in 1/2 women with EMG perineometry; isolated adductor muscle contraction: non-pelvic muscle induced readings in 6/11 women with EMG perineometry and in 2/11 women with pressure perineometry; Valsalva maneuver: non-pelvic muscle induced readings in 4/9 women with EMG perineometry and 9/9 women with pressure perineometry. It was concluded that EMG and pressure perineometry do not selectively depict pelvic floor muscle activity.     

Comparison of transperineal and transabdominal ultrasound in the assessment of voluntary pelvic floor muscle contractions and functional manoeuvres in continent and incontinent women

Transperineal (TP) and transabdominal (TA) ultrasounds were used to assess bladder neck (TP) and bladder base (TA) movement during voluntary pelvic floor muscle (PFM) contraction and functional tasks. A sonographer assessed 60 asymptomatic (30 nulliparous, 30 parous) and 60 incontinent (30 stress, 30 urge) women with a mean age of 43 (SD = 7) years, BMI of 24 (SD = 4) kg m² and a median parity of 2 (range, 0–5), using both ultrasound methods. The mean of three measurements for bladder neck and bladder base (sagittal view) movement for each task was assessed for differences between the groups. There were no differences in bladder neck (p = 0.096) or bladder base (p = 0.112) movement between the four groups during voluntary PFM contraction but significant differences in bladder neck (p < 0.004) and a trend towards differences in bladder base (p = 0.068) movement during Valsalva and abdominal curl manoeuvre. During PFM contraction, there was a strong trend for the continent women to have greater bladder neck elevation (p = 0.051), but no difference in bladder base movement (p = 0.300), when compared to the incontinent women. The incontinent women demonstrated increased bladder neck descent during Valsalva and abdominal curl (p < 0.001) and bladder base descent during Valsalva (p = 0.021). The differences between the groups were more marked during functional activities, suggesting that comprehensive assessment of the PFM should include functional activities as well as voluntary PFM contractions. TP ultrasound was more reliable and takes measures from a bony landmark when compared to TA ultrasound, which lacks a reference point for measurements. TA ultrasound is less suitable for PFM measures during functional manoeuvres and comparisons between subjects. Few subjects were overweight so the results may not be valid in an obese population.     

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

Clinical evaluation of pelvic floor muscle function in continent and incontinent women

AIMS: The aim of the study was to investigate the reliability of a scoring system for the investigation of voluntary and reflex co-contractions of abdominal and pelvic floor muscles in lying, sitting, and standing positions in continent and incontinent women. METHODS: A visual inspection and digital (strength, tone, speed, and endurance) palpation scale was developed to measure the coordination of the lower abdominal and pelvic floor muscles. Inter-observer reliability of the scales was investigated in 40 continent and 40 incontinent women. Differences between the continent and incontinent group were analysed. RESULTS: Inter-observer reliability for the visual inspection scale showed kappa values between 0.91 and 1.00, for tone percentage of agreement ranged from 95 to 100% (superficial) and 95 to 98% (deep muscle). Weighted Kappa (K(w)) varied from 0.77 to 0.95 for strength and 0.75 to 0.98 for the inward movement of superficial and deep pelvic floor muscles. K(w) for coordination between the superficial and deep part of the pelvic floor muscles groups was from 0.87 to 0.88 and 0.97 to 1.00 for endurance and global speed of the pelvic floor contraction. The continent women exhibited significantly better coordination between the pelvic floor and lower abdominal muscles during coughing in all three positions. Also the superficial part of the inward movement, the feeling and the coordination of the pelvic floor muscles were significantly better in the continent group. CONCLUSIONS: Visual inspection and digital tests are easy and reliable methods by which insight can be gained into the multi-muscular activity and coordination of the pelvic floor and lower abdominal muscles in continent and incontinent women.     

Change in urethral pressure during voluntary pelvic floor muscle contraction and vaginal electrical stimulation

The purpose of the study was to compare the effect of voluntary pelvic floor muscle (PFM) contraction and vaginal electrical stimulation on urethral pressure. Twelve women with genuine stress incontinence, mean age 49.4 years (range 33–66) participated in the study. The urethral and bladder pressures were recorded simultaneously through a double-lumen 8 Ch catheter. The patients first performed three voluntary PFM contractions. Then two electrical stimulators, Conmax and Medicon MS 105, 50 Hz, were used in random order. A visual analog scale was used to measure pain and discomfort. Pain was reported to mean 6.8, SEM 0.64 (range 0.7–9.9) and mean 6.1, SEM 0.81 (range 0–9.1) with Conmax and Medicon MS 105, respectively. The mean paired difference in favor of voluntary contraction with Conmax was ?8.0, SD 6.7,P=0.0067, and with Medicon MS 105 it was ?12.2, SD 5.9,P=0.0022. The results demonstrated that voluntary PFM contraction increased urethral pressure significantly more than did vaginal electrical stimulation.     

Pressure measurements during pelvic floor muscle contractions: The effect of different positions of the vaginal measuring device

The purpose of the present investigation was to assess whether different positions of the vaginal measuring device affect the pressure readings during pelvic floor muscle (PFM) contraction. Twelve women with stress urinary incontinence (SUI) participating in a PFM exercise program, volunteered for the study. The diagnosis of SUI was based on urodynamic investigation and pad test. The mean age of the women was 40.9 years (24–50). The women performed three PFM contractions with a vaginal balloon placed in four different positions: 1) against the vaginal vault and in the posterior fornix, 2) in the proximal upper third of the vagina, 3) with the middle of the balloon 3.5 cm from the introitus vagina and 4) with half of the balloon outside the introitus vagina. The results demonstrated significant differences between recordings from the four vaginal positions: position 1, median pressure 5 cm H₂O; position 2, 9 cm H₂O; position 3, 15 cm H₂O; and position 4, 8 cm H₂O. It is concluded that the position of the vaginal device affects the results. This may be one important factor which could explain the variability of vaginal pressure recordings during PFM contractions. For most women the highest pressure was recorded in position 3. © 1992 Wiley-Liss, Inc.     

Pelvic floor muscle evaluation in incontinent patients

The aim of this study was to assess pelvic floor muscle (PFM) strength and perception and its correlation with stress urinary incontinence (SUI). One hundred and one women were divided into two groups according to the presence (G1=51 patients) or absence (G2=50 patients) of SUI. Subjective [urine stream interruption test (UST), visual survey of perineal contraction and transvaginal digital palpation to assess pelvic muscle contraction] and objective evaluations of pelvic floor muscles in all patients were performed (vaginal manometry). During the UST, 25.5% of G1 patients and 80% of G2 patients were able to interrupt the urine stream (p<0.05). Digital evaluation of pelvic muscular contraction showed higher strength in G2 than in G1 patients (p<0.0001). Perineometer evaluation of PFM strength was significantly higher in the continent group (p<0.001). Pelvic floor muscle weakness in incontinent patients demonstrates the importance of functional and objective evaluation of this group of muscles.This revised version was published online in February 2005 with corrections to the third authors name. The name of this author, De Oliveira Orsi Gameiro M, was not correctly rendered in the original version.     

Pelvic floor muscle function in continent and stress urinary incontinent women using dynamometric measurements

AIMS: To compare the pelvic floor muscle (PFM) function in continent and stress urinary incontinent women using dynamometric measurements. METHODS: Thirty continent women and 59 women suffering from stress urinary incontinence (SUI), aged between 21 and 44 and parous, participated in the study. An instrumented speculum was used to assess the static parameters of the PFM: (1) passive force at 19 and 24 mm of vaginal aperture (antero-posterior diameter), (2) maximal strength in a self-paced effort at both apertures, (3) rate of force development and number of contractions during a protocol of rapidly repeated 15-sec contractions, and lastly (4) absolute endurance recorded over a 90-sec period during a sustained maximal contraction. The parameters described in the two latter conditions were assessed at the aperture of 19 mm. Analyses of covariance were used to control the confounding variables of age and parity when comparing the PFM function in the continent and incontinent women. RESULTS: The continent women demonstrated higher passive force at both openings and a higher absolute endurance as compared to the incontinent women (P < or = 0.01). In the protocol of rapidly repeated contractions, the rate of force development and number of contractions were both lower in the incontinent subjects (P < or = 0.01). The differences between the two groups for maximal strength at the 19- and 24-mm apertures did not reach the statistically significant level. CONCLUSIONS: The PFM function is impaired in incontinent women. The assessment of PFM should not be restricted to maximal strength. Other parameters that discriminate between continent and incontinent women need to be added to the PFM assessment in both clinical and research settings.     

Assessment of pelvic floor movement using transabdominal and transperineal ultrasound

The aims of the study were (1) to assess the reliability of transabdominal (TA) and transperineal (TP) ultrasound during a pelvic floor muscle (PFM) contraction and Valsalva manoeuvre and (2) to compare TA ultrasound with TP ultrasound for predicting the direction and magnitude of bladder neck movement in a mixed subject population. A qualified sonographer assessed 120 women using both TA and TP ultrasound. Ten women were tested on two occasions for reliability. The reliability during PFM was excellent for both methods. TP ultrasound was more reliable than TA ultrasound during Valsalva. The percentage agreement between TA and TP ultrasound for assessing the direction of movement was 85% during PFM contraction, 100% during Valsalva. There were significant correlations between the magnitude of the measurements taken using TA and TP ultrasound and significant correlations with PFM strength assessed by digital palpation.     

Incontinent women have altered pelvic floor muscle contraction patterns

PURPOSE: Pelvic floor exercises are invaluable for regaining continence but mechanisms are not fully understood. To contribute to the understanding of these mechanisms we investigated the contraction sequence of superficial vs deep pelvic floor muscles in 6 positions in continent and incontinent women. MATERIALS AND METHODS: The onset of contraction of the superficial and deep pelvic floor muscles was recorded by perineal and intravaginal surface electromyography in 32 continent and 50 incontinent women. The agreement between perineal and intravaginal recordings was calculated with the kappa statistic and the percent of agreement. Differences in onset between superficial and deep pelvic floor muscle contractions are reported as the median and IQR. RESULTS: Perineal and intravaginal electromyography recordings used to define the onset of muscle activity showed a high level of agreement. In the continent group the superficial muscles almost always contracted before the deep muscles in all 6 positions. In the incontinent group the reverse sequence was observed in 3 of 6 positions. Higher and less consistent time differences in the onset of contraction of the 2 muscle layers were found in incontinent vs continent women. CONCLUSIONS: Contractions of the superficial and deep pelvic floor muscles can be recorded by intravaginal or perineal electrodes. A consistent contraction sequence can be found in continent women but it is lacking in incontinent women. This might be a possible explanation for incontinence. Including differentiated muscle contraction exercises in pelvic floor muscle exercise programs may further optimize treatment outcomes.     

Pelvic floor muscle exercise for the treatment of female stress urinary incontinence: III. Effects of two different degrees of pelvic floor muscle exercises

Fifty-two women, mean age 45.9 years (24–64) with clinically and urodynamically proven stress urinary incontinence (SUI) were randomly assigned to one of two different pelvic floor muscle (PFM) exercise groups. Both groups performed 8–12 maximal PFM contractions 3 times a day for 6 months. In addition one group exercised with an instructor intensively 45 min once a week performing long-lasting contractions with the supplement of 3–4 fast contractions at the end of each long-lasting contraction. Initially and after 6 months an examination was performed comprising history, urinary leakage index, pad test, maximum urethral closure pressure, functional urethral profile length, and recording of vaginal pressure during PFM contractions. The latter was performed monthly. After the treatment 60% of the intensive exercise (IE) group and 17.3% of the home exercise (HE) group reported to be continent or almost continent (P < .01). Only the IE group demonstrated significant reduction in urine loss; from mean 27 g to 7.1 g (P < .01) and improvement in maximum resting urethral closure pressure (mean improvement 4.6 cm H₂O. P = .02). PFM strength improved with mean 15.5 cm H₂O (P < .01) in the IE group while the HE group improved with 7.4 cm H₂O (P < .01). It is concluded that the results of PFM exercise for female SUI is highly dependent upon the degree and duration of treatment and frequent supervision by the therapist.     

The effect of abdominal and pelvic floor muscle activation on urine flow in women

Introduction and hypothesis

Interruption of urine flow during micturition has been used as an assessment of ability to voluntarily contract the pelvic floor muscles (PFM). However, the PFM are also activated during specific abdominal manoeuvres. This study aimed to assess the effect of similar abdominal manoeuvres on urine flow and compare this with the effect of PFM contraction.

Methods

Eight healthy women, of mixed parity, contracted the abdominal muscles and the PFM during urine flow on separate occasions. Differences in urine flow were compared using paired t tests.

Results

All participants were able to interrupt the urine stream using both muscle activation patterns. There was no difference in the time taken to interrupt urine flow (p?=?0.78) between the two patterns.

Conclusions

These data provide evidence that specific abdominal muscle manoeuvres influence urethral closure in continent women, and this is probably mediated by concurrent activation of PFM during the abdominal task.     

Evaluation of pelvic floor muscle function in a random group of adult women in Austria

Despite an increasing clinical interest in female pelvic floor function, there is a lack of data with respect to the knowledge of average adult women about the physiological role of the pelvic floor and their ability to contract pelvic floor muscles (PFM) voluntarily. It was the aim of our study to evaluate the percentage of PFM dysfunction in adult women and the impact of risk factors, such as age, body mass index (BMI), number of children delivered, and the influence of previous PFM training. A total of 343 Austrian adult women (mean age, 41.2 ± 14.6 years; range, 18–79 years), selected at random, were examined to test their ability to contract the PFM. The examination was carried out by three independent gynecologists during the course of a routine gynecological visit. The ability to contract the PFM voluntarily or involuntarily was assessed by digital intravaginal palpation with the patients in a supine position. The muscle strength was graded according to the Modified Oxford Grading Scale by Laycock. A high percentage (44.9%) of the women was not able to voluntarily perform a normal PFM contraction. In only 26.5%, an involuntary contraction of the pelvic floor was present before an increase in intra-abdominal pressure. The inability to contract the PFM did not correlate with women’s age but revealed a weak relationship with the number of childbirths and the patient’s BMI. A significant correlation was found between the Oxford Grading Scale rating and the patient’s report about previous PFM training.     

Effect of abdominal and pelvic floor tasks on muscle activity, abdominal pressure and bladder neck

Introduction and hypothesis  

Although the bladder neck is elevated during a pelvic floor muscle (PFM) contraction, it descends during straining. This study aimed to investigate the relationship between bladder neck displacement, electromyography (EMG) activity of the pelvic floor and abdominal muscles and intra-abdominal pressure (IAP) during different pelvic floor and abdominal contractions.     

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

The aim of the present study was to describe co-activity patterns of the striated urethral wall muscle and the pelvic floor muscles (PFM) during contraction of outer pelvic muscles. Six healthy nulliparous physical education students, mean age 19.5 years (19–21) participated in the study. Concentric needle EMG and a Dantec amplifier were used for registrations. EMG activity was continuously recorded with the participants lying in a supine position. EMG was recorded during relaxation, contraction of the PFM. valsalva maneuver, coughing, hip adductor contraction, gluteal muscle contraction, backward tilting of the pelvis, and sit-ups. The procedure was performed with the needle in the striated muscle of the anterior wall of the urethra and then repeated with the needle set lateral to the urethra in the PFM. The results showed that the striated urethral wall muscle was contracted synergistically during PFM, hip adductor, and gluteal muscle contraction, but not during abdominal contraction. Both hip adduction, gluteal muscle, and abdominal muscle contraction gave synergistic contraction of the PFM. Thus the urethral wall striated muscle and the PFM react differently during abdominal contraction. © 1994 Wiley-Liss, Inc.