Task-specific differences in respiration-related activation of deep and superficial pelvic floor muscles

The female pelvic floor muscles (PFM) are arranged in distinct superficial and deep layers that function to support the pelvic/abdominal organs and maintain continence, but with some potential differences in function. Although general recordings of PFM activity show amplitude modulation in conjunction with fluctuation in intra-abdominal pressure such as that associated with respiration, it is unclear whether the activities of the two PFM layers modulate in a similar manner. This study aimed to investigate the activation of the deep and superficial PFM during a range of respiratory tasks in different postures. Twelve women without pelvic floor dysfunction participated. A custom-built surface electromyography (EMG) electrode was used to record the activation of the superficial and deep PFM during quiet breathing, breathing with increased dead space, coughing, and maximal and submaximal inspiratory and expiratory efforts. As breathing demand increased, the deep PFM layer EMG had greater coherence with respiratory airflow at the frequency of respiration than the superficial PFM (P = 0.038). During cough, the superficial PFM activated earlier than the deep PFM in the sitting position (P = 0.043). In contrast, during maximal and submaximal inspiratory and expiratory efforts, the superficial PFM EMG was greater than that for the deep PFM (P = 0.011). These data show that both layers of PFM are activated during both inspiration and expiration, but with a bias to greater activation in expiratory tasks/phases. Activation of the deep and superficial PFM layers differed in most of the respiratory tasks, but there was no consistent bias to one muscle layer. NEW & NOTEWORTHY Although pelvic floor muscles are generally considered as a single entity, deep and superficial layers have different anatomies and biomechanics. Here we show task-specific differences in recruitment between layers during respiratory tasks in women. The deep layer was more tightly modulated with respiration than the superficial layer, but activation of the superficial layer was greater during maximal/submaximal occluded respiratory efforts and earlier during cough. These data highlight tightly coordinated recruitment of discrete pelvic floor muscles for respiration.

Activity of Deep and Superficial Pelvic Floor Muscles in Women in Response to Different Verbal Instructions: A Preliminary Investigation Using a Novel Electromyography Electrode

INTRODUCTION

Verbal instructions are used clinically to encourage activation of the pelvic floor muscles (PFM). Whether separate layers of PFM activate differently in response to instructions remains unknown.

AIM

To test the hypotheses that (i) instructions that aimed to bias activity of a specific muscle layer would increase activation of the targeted layer to a greater extent than the other layer, (ii) activity of individual PFM layers would differ between instructions, and (iii) PFM activity would be symmetrical for all instructions.

METHOD

PFM electromyography (EMG) was recorded using custom-designed surface electrodes in 12 women without PFM dysfunction. The electrode included 4 pairs of recording surfaces orientated to measure EMG from deep and superficial PFM on each side. 3 submaximal contractions were performed for 5 seconds in response to 7 verbal instructions. Root-mean-squared EMG amplitude was calculated for 1 second during the period when participants most closely matched the target activation level. A repeated-measures anova was used to test whether PFM EMG differed between instructions and between regions. The EMG increase of individual muscles relative to that of the reference muscle [deep/right PFM] was compared to no change with t-tests for single samples.

MAIN OUTCOME MEASURE

PFM EMG amplitude.

RESULTS

Superficial PFM EMG was greater than deep PFM for all instructions (P = .039). 2 instructions induced the greatest amplitude of EMG for the superficial PFM: "squeeze the muscles around the vaginal opening as if to purse lips of your mouth" and "draw the clitoris in a posterior direction" (P = .036). Asymmetry was found in the deeper PFM in 3 instructions designed to bias the superficial PFM.

STRENGTH & LIMITATIONS

This preliminary study recorded activation of deep and superficial PFM layers in females with a custom-designed novel electrode. Some cross-talk of recording between muscle layers is possible but unlikely to impact the major findings.

CONCLUSION

Verbal instructions used to teach PFM contractions can influence their pattern of activity. This study provides preliminary evidence that, in a selection of verbal instructions, the superficial PFM activates more than the deep PFM, and that the deep PFM can have asymmetrical activation. Aljuraifani R, Stafford RE, Hall LM, et al. Activity of Deep and Superficial Pelvic Floor Muscles in Women in Response to Different Verbal Instructions: A Preliminary Investigation Using a Novel Electromyography Electrode J Sex Med 2019;16:673-679.

Design of programs to train pelvic floor muscles in men with urinary dysfunction: Systematic review

AIMS

Pelvic floor muscle training (PFMT) is a first line conservative treatment for men with urinary dysfunction, but reports of its efficacy are variable. This study aimed to systematically review the content of PFMT programs used for urinary dysfunction in men.

METHODS

Electronic databases (PubMed, CINAHL, EMBASE, Cochrane, PEDro) were searched for studies that used PFMT in the treatment of adult men with urinary dysfunction. Details of PFMT treatment sessions and home exercise protocols were extracted. Criteria specific to PFMT were developed, based on the Consensus on Exercise Reporting Template, and applied to all studies to measure the comprehensiveness of the PFMT description in the manuscript.

RESULTS

Results from the 108 included studies indicate substantial heterogeneity in both the content of PFMT and the quality of reporting of the components of the exercise regimes. There was notable disparity in the muscles targeted by the interventions (and few focused on urethral control despite the use in management of urinary conditions) and the intensity of the programs (eg, 18-240 contractions per day). Most studies were missing key details of description of the PFMT programs (eg, the position in which the pelvic floor muscle [PFM] contraction was taught and how it was assessed, methods used to ensure exercise adherence).

CONCLUSIONS

Variation in content of PFMT programs is likely to contribute to variation in the reported efficacy for management of urinary dysfunction in men, and unclear description of the details of the evaluated programs makes it difficult to identify the effective/ineffective components. PROSPERO registration number CRD42017071038.