"Just relax": the antidote to an overactive pelvic floor?
For many with pelvic floor muscles diagnosed as "overactive," the advice is to "relax first and contract later."
Whether it is a practice of breathing, meditation, manual therapy, or stretching, the common theme is one of avoiding pelvic floor muscle (PFM) contraction (through pelvic floor muscle training or during exercise that promotes PFM contraction) and attending to the PF to "relax" when tension or discomfort is sensed. Only once someone's pain symptoms are resolved, or their muscle tone is judged to be "normal," are they deemed appropriate for introduction of concentric PFM contractions (lifting) and exercise that places demand on muscle groups such as the gluts or abdominals. These interventions have certainly been demonstrated to benefit those in pain or experiencing other pelvic floor related symptoms, and we have emphasized encouraging the yielding of the pelvic floor for various scenarios in both the clinic and with our coursework. But is the preoccupation with avoiding contractions really the best way to address these concerns in the long run?
While elevated PF muscle tone is thought to play a role in pelvic floor pain diagnoses, studies have been limited by the difficulty of assessing it.
There is no universally accepted definition of “muscle tone,” but it is generally defined as the active and passive resistance to applied pressure or stretch.
Unlike most other skeletal muscle, the PFM demonstrates electrical activity at rest. Therefore, PFM tone assessment is taking into account both viscoelastic properties (passive) and resting electrical activity/reaction to stretch (active). Vaginal or rectal palpation, used clinically to assess muscle tone, is highly subjective and imprecise. While research is performed with technology that allows better objectivity and standardization, most providers will not have access to this.
Even if we were able to more objectively categorize PFM tone, studies that associate elevated PFM tone and muscle pain cannot determine causality. It would be impossible to determine with these study designs whether the altered PFM tone/activity occurred prior to pain or as a result of it. While many people with PF muscle pain have muscular overactivity or high muscle tone, not all people with higher muscle tone have pain.
We do not have evidence that implicates muscle tone as the causal factor for pain or functional impairments. However, we see many providers attempt to normalize muscle tone through passive interventions such as manual therapy before introducing active interventions - if they ever do. Surface EMG studies have shown that those with provoked vestibulodynia (PVD) demonstrate higher active and passive components of PFM tone than controls. They also demonstrated decreased strength, speed, coordination, and endurance of PFM activity.
Authors of The Overactive Pelvic Floor (2016) write:
“In conditions due to overactive pelvic floor, several authors emphasize that elevated PFM tone might not be the only muscle dysfunction and stress the importance of a broader assessment of muscle contractile properties. The assessment should therefore go beyond the properties at rest to evaluate the contractile properties such as strength, endurance, and speed of contraction.”
A study of young, nulliparous women with provoked vestibulodynia found significantly lower vaginal resting pressure and lower EMG activity after three maximal PFM contractions. This effect was demonstrated in both the group with vestibulodynia and the control group, but the control group did not show a change in EMG activity.
If this finding is accurate, we may be limiting our effectiveness with the assumption that active interventions are contraindicated for an overactive PF or someone with PF pain. In fact, the use of both isometric and dynamic contracts for muscle and tendon pain relief is commonly used in orthopedic practice. This "exercise-induced hypoalgesia" appears to have a greater local than systemic effect, meaning the area around the contracting muscle has the most pain relief.