Pelvic Floor: Integration Versus Isolation

Julie W. Wiebe

LEARNING OBJECTIVES

After reading this chapter you should be able to:

Expand the definition of pelvic floor function.
Understand the pelvic floor as a component of the central stability system.
Understand and optimize the interrelationship between diaphragm, abdomen, and pelvic floor.
Promote system availability via optimized alignment.
Gain direct and indirect tools to assess the function of the pelvic floor.
Promote an integrated model of diaphragm and pelvic floor interaction as the foundation of a dynamic system of stability.
Link anticipatory to reactive core components (deep to superficial) to promote optimized movement patterns, function, fitness, and performance.
Understand the value of pelvic floor integration to promote simultaneous neuromuscular, musculoskeletal, performance, and pelvic health issue improvement for the clients in your carer.

“I did then what I knew how to do. Now that I know better, I do better.

–MAYA ANGELOU

Introduction

The classically understood concepts, theory, and practice surrounding the pelvic floor (PF) have primarily focused on this group of muscles as self-contained and isolated in function (Fig. 33.1). The PF has long been understood as the principal protector and promoter of continence, pelvic organ support, and sexual function. Issues with these vital physiologic priorities have been attributed to either a PF that is too weak or too strong, too long or too short.

The emergence of theoretical constructs and clinical transitions toward integrative models that examine and treat functional movement patterns, optimize neuromuscular relationships, and promote systems-based interventions begs the question: Why has the primary intervention strategy for the PF remained only isolated strengthening activities such as a Kegel?

Figure 33.1 Female pelvic floor (deepest layer in purple: levator ani) is a grouping of three of the muscles of the pelvic floor: pubococcygeus, iliococcygeus, and puborectalis; the final muscular component in blue is the ischiococcygeus. The two more superficial layers in pink, yellow, and green collectively represent components of the urogenital triangle and include the sphincters (Image Samantha Cattach, PT, B.Phty www.bodyandbirthphysio.com).

New evidenced-based, integrative clinical models for inclusion of the PF must emerge that mimic our understanding of how other muscle groups are rehabilitated and trained for function, fitness, and performance.

In this chapter, we will explore the emerging evidence for a new understanding of the function of the PF as it relates to its anatomical and neuromuscular partnerships. Primary PF synergistic relationships or teammates include the diaphragm (D), transversus abdominis (TA), and multifidus (M). Secondary
synergistic relationships/teammates include, but are not limited to, the gluteals, latissimus dorsi, obliques, adductors, and hip lateral rotators.

When the PF is understood as teammate versus spectator, a change in thinking and practice must occur:

Teamwork with functional partnerships optimizes the capacity of the PF to meet its physiologic priorities, and thus the rest of the team is critical to the maintenance of continence.
Conversely, the capacity of the primary and secondary synergistic teams to promote postural control, movement support, and performance will be enhanced through partnership with the PF.
Continence can be understood as one of many signals that this team is not functioning in a coordinated way versus the PF alone is weak.
Conversely, dysfunction in trunk and pelvic control, movement, and performance must take into consideration PF participation or lack thereof as a component of that dysfunction.
If it has a role in the dysfunction, then the PF has a role to play as a part of the solution for that dysfunction.

This chapter seeks to illuminate the PF as a teammate, not a spectator and provide clinical steps for integration into current programming.

Pelvic Floor as Teammate

In a 2007 study by Smith et al,¹ 14 continent and 16 incontinent women were divided into three cohorts: continent, mildly incontinent, and severely incontinent. The participants were asked to catch a 1 kg weight dropped from 30 cm in a bucket. Probe and surface electromyography (EMG) captured the response of the PF, abdominal, gluteal, adductor, and lower extremity (LE) musculature. It was hypothesized that the women with severe incontinence would demonstrate the least EMG activation of the PF in response to postural perturbation. The authors were surprised to find that the continent women demonstrated the least, whereas the severely incontinent women generated the greatest EMG activation of the PF. It was noted that the severely incontinent group also demonstrated the greatest activation of the external obliques (EO). This added muscular force and intra-abdominal pressure (IAP) generation from above was thought to have overwhelmed the large efforts of the PF beneath, leading to leakage. The authors noted, “Differences in pelvic floor and external oblique EMG in incontinent women reinforce the need to consider the interaction between muscle groups, rather than the isolated evaluation of pelvic floor muscle activity.” Although strengthening components of the system continues to have importance, a singular clinical focus on more activation of the PF in the study participants would not resolve the muscular imbalance that was thought to have triggered leaks.

Instead, optimization of these muscular interactions was demonstrated in the response of the continent women to the perturbation. This was a small task; the women were asked to catch 1 kg = 2.2 lb, not 50 lb. The demand on the system was small. The continent women demonstrated a balanced, efficient, and appropriate response to that level of demand. This supports the need for neuromuscular coordination of the components of the system in order to create graded responses and the automaticity of the system required to efficiently meet demand.

Understanding the System

The primary synergistic system (aka the anticipatory system) is comprised of the D, TA, PF, and M. Each acts in an anticipatory way, preparing and anchoring the center in a predictable way prior to movements.²^,³^,⁴ The PF has been shown to predict and engage to prepare for arm movement,⁴ abdominal activation,⁵ leg movement,⁶ and heel strike in running.⁷

The secondary postural system (aka the reactive system) has been shown to respond in a variable way depending on the demands of the task.³ The marriage of these two systems, anticipatory and reactive, via an inside-out recruitment order prepares for, produces, and optimizes function and movement.

Talasz⁸ provided dynamic magnetic resonance imaging footage of the interaction between the anticipatory system components during the respiratory cycle. On inhalation, the D descends, the waist circumference broadens, and the PF lowers. On exhalation, the diaphragm ascends, the waist moves inward, and the PF rises. Please note the excursion of each of the components of the system varied in response to the demand. Mean excursion values for quiet breathing, forced breathing, and coughing are presented in Table 33.1.

This automatic interaction is a response in part to pressure gradient changes that occur during the respiratory cycle. As the diaphragm descends, IAP
increases; the TA⁹ and PF respond to this pressure by lengthening.⁴^,⁸ This elastically loads them to facilitate a recoil response on exhalation when IAP is diminished. This coordinated, pistoning interplay between muscular force and pressure provides both inhalation and exhalation stability in a dynamic system of central control. Excursion in all components is necessary to coordinate their opposing actions, create a graded response to different demands, and for force attenuation either from above (IAP, muscular force, or load) or from below (impact control, or load).⁸

Table 33.1 Mean Excursion Values for Quiet Breathing, Forced Breathing, and Coughing

	Quiet Breathing (mm)	Forced Breathing (mm)	Coughing (mm)
Diaphragm (R)	15 ± 6	32 ± 15	32 ± 13
Diaphragm (L)	9 ± 7	28 ± 16	28 ± 7
Abdomen (waist circumference)	5.1	10.4	9.2
Pelvic floor	2.1	7.0	3.8
Values represent the mean. Pelvic floor excursion varied, but always moved cranially on exhalation. Abdominal excursion varied but always moved inward on exhalation.⁸ From Talasz H, Kremser C, Kofler M, Kalchschmid E, Lechleitner M, Rudisch A. Phase-locked parallel movement of diaphragm and pelvic floor during breathing and coughing: a dynamic MRI investigation in healthy females. Int Urogynecol J. 2011;22(1):61-68.

Balancing the relationship between these components becomes a new gateway to integration of the PF into rehab and training programs. It creates a win-win for pelvic health concerns, trunk and pelvic control deficits, their relationship to musculoskeletal issues, and vice versa.

The results of two studies performed by Smith et al support the suggestion that the muscles of continence and respiration (D, TA, and PF) also contribute to trunk control, a lack of which is a common deficit noted in those with low back pain (LBP). In 2006, Smith’s team looked at self-reported data from 38,050 responses to a mailed survey. Women in three age cohorts (18-23, 45-50, and 70-75) reported incidence of LBP in the previous 12 months, along with factors often associated with LBP such as body mass index and physical activity. Only incontinence and allergies significantly correlated with the presence of LBP across all three cohorts. Other respiratory issues (asthma) significantly correlated with LBP in the middle and older cohorts.¹⁰

A follow-up survey was performed at 4, 2, and 3 years for the same age cohorts (respectively 2,943 younger, 2,298 middle, 2,258 older). A significant correlation was noted between those who had developed incontinence or breathing difficulties since the original survey with the development of LBP in the prior 12 months across all three age cohorts.¹¹

Optimizing the System

The Role of Alignment

It is understood that structural alignment has the capacity to enhance or diminish the availability of musculature. Burtner et al asked typically developing children to assume the crouched stance common in children with cerebral palsy (CP). The neurologically typical participants demonstrated a nonoptimal pattern of LE muscular recruitment similar to that of the children with CP. This pattern was previously attributed only to birth or neonatal neurologic injury, but now understood in part as a product of the position itself.¹²

Structural alignment has also been shown to influence the recruitment of the anticipatory and reactive system components to support their availability for trunk and pelvic control. Sapsford¹³^,¹⁴ and Claus¹⁵ reported that the resting activation of components of both anticipatory (PF, TA, M) and reactive (internal oblique and EO, rectus abdominis) systems changed when both lumbo-pelvic and thoraco-spinal position variables were manipulated. Enhanced resting activation of the anticipatory components (TA, M, and PF) was noted when adults maintained relative neutral positions labeled “upright,” “upright unsupported,” or “short lordosis.”¹³^,¹⁴^,¹⁵ Resting activation of the PF was diminished in positions of posterior pelvic tilt.¹³^,¹⁴

Defining Neutral Range

For our purposes, the term “neutral range” will be utilized as the optimized position for enhancing availability and responsiveness in the anticipatory and reactive systems to support postural control, movement, and to meet physiologic priorities for each individual. We do not have any true normative values, evidence of what neutral really is, or what it is supposed to look like in order to define it specifically. Therefore, rather than define this range as a specific
position, we will discuss it in terms of optimized availability and interaction of the system components relative to the structural and neuromuscular capacity and physical history of each individual.¹ Neutral range will provide a starting point to maximize the coordinated relationship between the IAP pressure system and interplay of the D, TA, and PF and balance the activation of global flexors and extensors. This can be achieved by attention to the position of the rib cage relative to the pelvis, the patient’s “sweet spot.”

Harnessing the System: TAP

In order to successfully build a clinical model that accesses, integrates and optimizes the PF, we must incorporate a systems approach that enhances teamwork through optimized alignment, muscular recruitment order, and pressure system management. The ultimate goal is system automaticity. Clinical steps will include:

(T) Teamwork: Synchronize and balance the IAP pressure system and muscular components of the anticipatory system.
(A) Alignment: Address structural contributions to create an optimum environment for availability of the team.
(P) Preparation: Re-establish deep to superficial (anticipatory to reactive) strategies to build system automaticity.
Integrate with synergistic reactive postural stabilizers to support new form, proximal control, pressure management, optimized movement patterns, and function.
Address exercise, walking, running, and jumping form.
Make program specific to the demands placed on the system by the individual’s chosen fitness and sport.

Teamwork and Alignment

The position of the rib cage, spine, and pelvis are interconnected like pieces of a jigsaw puzzle. The position of one is counterbalanced and influenced by the other. Posterior translation of the rib cage relative to the pelvis reduces lumbar lordosis, elevates the apex of the lumbar curve toward the thora-columbar (T-L) junction, and increases posterior pelvic and sacral tilt.¹⁶ Alignment of these structural components contributes to the availability, synchrony, and balance of the muscular and pressure systems. X-ray studies have indicated that women with pelvic organ prolapse tended to have a loss of lumbar lordosis, a larger pelvic inlet (associated with posterior tilt),¹⁷ and a greater kyphosis¹⁸ than controls. Alignment and effective teamwork are linked.

Optimized rib cage over pelvis alignment will maximize breathing mechanics as a critical first step to setting up the coordinated interplay of the pressure system, muscular forces, and automatic responsiveness of the PF.

Ribcage Position and Breath Mechanics

The rib cage tends to be either stacked over the pelvis (Fig. 33.2A) or translated posteriorly relative to the pelvis (Fig. 33.2B and Fig. 33.2C).

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