Photo via Joe Loong via Flickr
By Nicole Davis
In previous entries, Britt beautifully took us through all things posture (Posture and the Pelvis Part One and Part Deux). Here are some important takeaways from her posts to consider as we explore how sitting may affect your pelvic floor:
- The diaphragm, trunk (back extensors, transversus abdominis, obliques, etc.) and pelvic floor muscles are all part of your ‘core’
- Posture is not a position you hold but rather a state of balance
- Base of support, alignment and pressure are essential to maintaining your state of balance
- Sitting, standing or moving outside your state of balance can change the ideal length-tension ratio
- Altering the length-tension ratio can shorten or lengthen the muscle making them appear weak and less efficient
- Posture is dynamic and dysfunctional holding or movement patterns can manifest as or exacerbate pelvic symptoms
As you can see, posture is not as simple as “standing tall” or “sitting up straight.” Positioning your body in poor posture, especially for prolonged periods of time can lead to a breadth of pelvic floor dysfunctions. This may include pain with sitting, coccydynia, low back pain, urinary frequency, incontinence, etc. Living in the Bay Area, a world of technology, finance and commutes I come across many patients with the hallmark slumped sitting posture – their heads, shoulders and low back are all rounded forward. It is not uncommon for me to hear at a patient’s first visit, “I sit eight plus hours a day at work” or “I travel two hours one way to get to the office” or “I frequently fly across the country for my clients.” Whichever the response, this is too much sitting and could potentially lead to dysfunction later down the road.
It has been cited in numerous studies that sustained pressure can lead to mechanical deformation and tissue ischemia with muscle being the most susceptible tissue.2 These reactions also occur in the skin and other subcutaneous tissues especially around bony prominences. In regards to sitting this may include your sitz bones, tailbone, sacrum or low back. Here are two illustrations of how this may impact pelvic symptoms:
Mechanical deformation → altered muscle length-tension ratio → inefficient functioning muscles → frequency, incontinence, pain, etc.
Ischemia → less blood flow → decreased oxygen → pain
So how often should one take a break from sitting? In a systematic review addressing pressure ulcers in patients with spinal cord injuries, authors reported that it takes approximately two minutes of pressure relief to unload transcutaneous tissue and raise local oxygen perfusion. They suggest this be performed every fifteen to thirty minutes.4 Unfortunately, this is unrealistic for the working person and thankfully we tend to shift as we sit anyways. As a rule of thumb, I typically recommend patients get up at least every hour or so and walk at least two minutes.
The Centers for Disease Control and Prevention (CDC) also recognize the consequences of prolonged sitting and have even piloted studies for intervention in the workplace. Though they do not site specific pelvic symptoms due to prolonged sitting, the CDC has reported correlation with premature mortality, obesity and many chronic conditions such as cardiovascular disease and diabetes. No worries though, it appears that taking frequent breaks from sitting may lower these health risks. In the CDC’s Take-a-Stand Project, individuals that had access to a standing workstation reduced their sitting time by 224%; 66 minutes a day. They also reported reduction in upper back and neck pain and even improvements in their mood.3 It’s important to also note that those who were provided a standing desk did not stand all day. The key is to find a balance of standing, sitting and moving.
If your company offers an ergonomic assessment, DO IT! If not, push for it. If still unsuccessful, you can follow these tips for general sitting posture:
- Maintain the natural s-shaped curve of your spine with your head slightly tucked and shoulder rolled down and back
- If able, hands should be positioned up vs. down to facilitate external rotation of your shoulders to prevent rounding of your shoulders and head
- Lumbopelvic position in neutral with weight centered equally on both sitz bones (*more on this below)
- Ideally, your hips should be slightly higher than or in line with your knees, creating a 90 degree angle
- The back of your thighs should be in contact throughout the seat of the chair vs. the edge of chair. This distributes the pressure over a larger surface area, decreasing the demands of any one area of your thighs or buttocks
- Feel flush with floor or a stool if on the shorter side and equal weight bearing through your feet
Kaiser Permanente has a pretty awesome interactive page with detailed explanation on how to incorporate these tips in the workplace i.e. ergonomics. I highly recommend you check it out.
*A little more on neutral pelvis…
Maintaining a neutral pelvis in sitting can have a great impact on keeping your pelvic floor healthy and efficient. Why is this so important and how can you achieve a neutral pelvis? As we mentioned before, your pelvic floor muscles are one of your postural muscles, they are essential to maintaining your balance. They create this bowl that slings from the pubic bone and attaches back onto the tailbone and sacrum. In addition to keeping you stable, the pelvic floor muscles also play an important role in supporting the internal organs (bowel, bladder, prostate and uterus). When you fall outside a neutral pelvis, you alter the length-tension ratio of the pelvic floor muscles. This may either shorten or lengthen the pelvic floor muscles, making them less efficient. Tight or overstretched muscles can either create pain or make it difficult to support the internal organs. Let’s use the urinary system as an example. If your pelvic floor muscles are hypertonic, this may give you feedback that you have to urinate even though you may have nothing to void. There is only so much space within the pelvis so when the pelvic floor muscles are resting in an “up and in state” it can make you feel like you have to pee. On the other hand, if you pelvic floor muscles are positioned in a lengthen state, they can exacerbate feelings of vaginal heaviness or incontinence as they are not properly supporting the bladder or urethra.
Having a neutral pelvis also means maintaining the natural concave curve of the lumbar spine. Oftentimes in clinic, most patients are flattened or rounded in their low back (hypolordotic) but we have also seen patients that are excessively arched (hyperlordotic). What does this mean for the pelvic floor? In a study out of Canada, researchers looked at the impact of lumbopelvic position on the pelvic floor muscles in standing. All participants (healthy, nulliparous women ages 22 – 41) performed five different tasks (static standing, maximal effort cough, Valsalva maneuver, maximal effort voluntary pelvic floor contraction and a load-catching contraction) in three different lumbopelvic positions; normal lumbopelvic posture, hyperlordosis and hypolordosis. Electromyographic (EMG) activity was collected using a vaginal sensor to monitor the activity of the pelvic floor and external sensors were placed on the trunk muscles (rectus, external and internal obliques and erector spinae). Interestingly, EMG activity in standing hypolordotic was higher than normal posture. During activities of maximum pelvic floor contraction, cough, Valsalva and load-catching there was less EMG activity for the hyperlordotic and hypolordotic positions compared to normal.1 What might this information suggest? (1) Strengthening of the pelvic floor muscles may be more effective in a neutral position for patients that have low tone and (2) patients that are chronically holding oftentimes in a hyperlordotic posture, may be perpetuating their dysfunction by placing excessive pressure on internal organs.
So, how do you find neutral? To find your neutral pelvis in sitting, try shifting your pelvis forward (anterior tilt) and backwards (posterior tilt). The goal is to find the balance between these two positions. As you are shifting your weight, you are looking for the position in which you feel pressure equally beneath your sitz bones. You will also feel slight tension anteriorly at your pubic bone. This is neutral. The position where your pelvic floor muscles are most efficient. If you are cleared to kegel, one way you can test this is by kegeling in each position. Notice that when you perform a kegel in either an anterior or posterior tilt, the range of motion of the pelvic floor muscles is less. That is, the pelvic floor muscles travel a shorter distance up when contracted and down when relaxed. When you are truly in neutral, you will feel as though you have a stronger contraction likely because the pelvic floor muscles are now able to move through their entire available range of motion.
While first practicing these new positions, you WILL feel off. That’s expected. You are teaching yourself a new way to be in your body. The brain is a marvelous organ but can cling on to what it already knows. You will likely have to “check in” but eventually you will find a new normal that will help you engage the appropriate muscles to keep you balanced. If you are having difficulty using these tips for optimal seating posture and are also experiences pelvic floor symptoms, we would love to see you! With years of holding, there may be myofascial restrictions (i.e. tight hamstrings, pecs, etc.) that may make it difficult to successfully maintain the natural curves of your spine and a neutral pelvis.
- Capson AC et al. The role of lumbopelvic posture in pelvic floor muscle activation in continent women. J Electomyogr Kinesiol. 2011;21(1):166-77.
- Cardenas, D & Dalal, K. Spinal Cord Injury Rehabilitation. Physical Medicine and Rehabilitation Clinics of North America. Pg. 643
- Nicolass Pronk et al. Reducing occupational sitting time and improving worker health: the take-a-stand project, 2011. Prev Chronic Dis 2012;9
- Regan et. al. A systematic review of therapeutic interventions for pressure ulcers after spinal cord injury. Arch Phys Med Rehabil. 2009;90(2):213-31