The Ankle Bone is Connected to the Pelvic Floor Muscle Function

In Pelvic Floor Dysfunction by Shannon PacellaLeave a Comment

By: Shannon Pacella

With Halloween just occuring, I had been seeing skeleton decorations everywhere and it got me thinking about anatomy. Cue the ‘Dem Bones’ song we sang as kids – “the knee bones connected to the thigh bone, the thigh bones connected to the hip bone,” the ankle bones connected to the pelvic floor…wait, I didn’t think that’s how the song went!

So the ‘ankle bone’ (the ankle is a joint) does not directly connect to the pelvic floor, but it may have some influence on pelvic floor muscle function. I wanted to explore this further and found a few research articles that looked at just that – how ankle position affects pelvic floor muscle (PFM) contraction. Most of the research I found looked specifically at how this may affect people with stress urinary incontinence (SUI).

Here’s a quick overview of ankle positions I will be mentioning:

  • Ankle neutral/horizontal is when the feet are flat on the ground.
  • Ankle dorsiflexion is when the heels are down and toes are lifted upwards; this can be done passively (with a wedge under the toes or actively by using your muscles to lift the toes up).
  • Ankle plantar flexion is when the toes are down and the heels are lifted upwards (position of feet in high heels); this can be done passively with a wedge under the heels, or actively by using your muscles to lift the heels up).

Photo by Connexions

The first research article Relationship between ankle position and pelvic floor muscle activity in female stress urinary incontinence by Chen et al., looked to determine whether pelvic tilt, as changed by various ankle positions, influences PFM activity in women with SUI.1 39 women who had been diagnosed with SUI were instructed to perform three maximal PFM contractions, with a ten second rest between each contraction; PFM activity was measured by electromyographic (EMG) biofeedback via intravaginal probe and surface electrodes.1

The three different positions being tested were:

  • Horizontal standing – neutral pelvic tilt posture.
  • Standing with the ankles dorsiflexed (passively on a board inclined 15 degrees) – this results in anterior pelvic tilt posture (butt/tailbone sticking out).
  • Standing with the ankles plantar flexed (passively on a board declined 15 degrees) – this results in posterior pelvic tilt posture (butt/tailbone tucked underneath).

Maximal PFM contraction was highest in standing with ankles dorsiflexed, second best maximal PFM contraction was in the horizontal standing position, and the weakest maximal PFM contraction was in the standing with ankles plantar flexed position. The anterior pelvic tilt provided increased PFM activity during ankle dorsiflexion. This movement (anterior pelvic tilt) results in the closure of the urethra, bladder neck, and suburethral vaginal wall, and urethral support is elevated.1 These findings may be helpful when treating those with SUI, to train PFM contractions in a standing position with toes lifted by a wedge/towel roll and in an anteriorly tilted pelvic posture.

A second research article by Chen HL et al. entitled, The effect of ankle position on pelvic floor muscle contraction activity in women, looked at the effects of passive and active ankle flexion positions on PFM activity.2 When this study was done, there were no other known studies that had looked at active ankle positions and PFM activity. The researchers hypothesized that active ankle positions would result in greater PFM activity.2 31 women comprised of a mix of those with and without SUI, were instructed to perform the same amount and timing of PFM contractions (three maximal PFM contractions, with a ten second rest between each contraction) that were measured with the same equipment (EMG biofeedback via intravaginal probe and surface electrodes) as the previous study.

The nine different positions being tested were:

  • Horizontal standing (HS)
  • Standing passive dorsiflexion with 2.5cm block under toes (2.5 DF)
  • Standing passive dorsiflexion with 4.5cm block under toes (4.5 DF)
  • Standing active dorsiflexion (DF)
  • Standing active dorsiflexion with arms raised up (DFAU)
  • Standing passive plantar flexion with 2.5cm block under heels (2.5 PF)
  • Standing passive plantar flexion with 4.5cm block under heels (4.5 PF)
  • Standing active plantar flexion (PF)
  • Standing active plantar flexion with arms raised up (PFAU)

The image below was included in the research article2 to give you a better idea of each position.

The greatest PFM contraction was seen in the active plantar flexion with arms up position (PFAU); the second best position for PFM contraction strength was in passive dorsiflexion on a 4.5cm block (4.5 DF).2 The researchers suggested that the PFAU position resulted in simultaneous abdominal, back, thigh, and leg muscle contractions in order to maintain posture.2 This co-activation of surrounding muscles enhanced the PFM contraction force.

So what do these findings mean for clinical practice? This research has shown that different ankle positions can influence PFM contraction by changes made in pelvic positioning and surrounding muscle co-activation, which means the ankle bone is indirectly connected to the pelvic floor!

The first study found that passive ankle dorsiflexion resulted in an anterior tilt of the pelvis which enabled a stronger PFM contraction than posterior pelvic tilt (found during passive ankle plantar flexion). So even if you take the ankle movement out of the equation and just focus on pelvic position, it seems from this study that a more anteriorly tilted pelvic position may result in a stronger PFM contraction. To achieve this ideal anterior pelvic tilt position, I would recommend not going into the end range, but finding the position about halfway between a neutral pelvic position and the end range of anterior tilt. I explain this to patients by saying, “place your hands on your hips and gently rotate your hips forward so your fingers move downward and your thumbs move upward, and allow your buttocks to stick out slightly; make sure your hips are not rotated so far forward that they cannot go any further, you want to be about halfway between your starting point in a neutral position and the furthest forward you can rotate your hips.” This can be a helpful cue for patients during various PFM strengthening exercises in sitting, standing, and supine/hook lying positions. The second study found that active plantar flexion with arms raised up allowed for the strongest PFM contraction, which could have been secondary to other muscle group co-activation. That being said, when treating people with PFM weakness, I believe it is important to incorporate various challenging positions while performing the PFM strengthening exercises, when appropriate. This may include the PFAU position which I would have my patients get into by saying “stand on your tiptoes and raise your arms up to the ceiling.” But there are many other options that can facilitate muscle co-activation and potentially enhanced PFM contractions, such as standing on one leg, wall sit position, and side plank position to name a few.

If you are experiencing stress urinary incontinence or other symptoms that may be related to PFM weakness, the first step is to find a pelvic floor physical therapist, here at the Pelvic Health and Rehabilitation Center, we are happy to help! Each physical therapist will be equipped in giving you an individualized treatment and exercise plan to help achieve your goals. To learn more about pelvic floor physical therapy evaluation and treatment, click here. To find a pelvic floor physical therapist near you, click here.

 

Resources:

  1. Chen CH, et al. Relationship between ankle position and pelvic floor muscle activity in female stress urinary incontinence. Urology. 2005 Aug;66(2):288-92.
  2. Chen HL, et al. The effect of ankle position on pelvic floor muscle contraction activity in women. Urology. 2009 March; 181:1217-1223.

Leave a Comment