By: Gina Conley, MS Exercise Science
The SI Joints Dysfunction: Pregnancy Discomfort, Causes, and Solutions
The SI Joints are two posterior pelvic joints that attach the sacrum to the ilium. The SI joints are a major junction where we transfer load between our upper and lower body; this means a lot of force and stress is moved through these joints. Because the SI joints are such a crucial part of load transfer, there is a lot of musculature that supports these joints that could affect the balance between the two of them.
During pregnancy, we may find that we have increased SI joint pain as our pregnancy progresses. Joint laxity increases with each day of pregnancy, and will peak around delivery, then begin to drop after birth.
The SI joints will maintain equilibrium, but this does not mean that they will be equal to each other. One joint may become hypermobile, or move too much (instability), while the other responds by becoming hypomobile, or stops moving (restriction).
This can become exasperated during pregnancy for a number of reasons:
Joint laxity increases during pregnancy due to the hormone relaxin. This means that joints tend to move more, which is good news for our pelvis in regards to fetal descent but not good news in regards to stability.
Changes in postural habits and how we move during pregnancy can alter the force distribution in our joints, particularly our SI joints.
Musculature weakening of the muscles that support the SI joint.
So what can we do about this discomfort/pain other than not be pregnant?
We can focus on increasing the strength and then adding in focused mobilization.
Strengthen
We want to focus on strengthening with focused mobilization to increase the stability and overall function of the SI joints. If we only stretch, then we are missing half the necessary equation to solve our problem: stretching is generally not the solution during pregnancy for instability issues.
We can first focus on strengthening the posterior oblique sling, the movement sling that supports the SI joints! The Posterior Oblique Sling runs diagonal across the SI joints from the latissimus dorsi (lats) to the opposite glute across the thoracolumbar fascia on the back of the pelvis. This sling stabilizes the SI joints (back two pelvic joints that connect the sacrum to the ilium), lumbar spine (low back), and hips. The SI joints acts as a major junction of force transfer from our upper to lower body! This means that these joints are fairly active in our daily function.
The functions of this sling include: pulling, outward rotation, transfer of force between the upper and lower extremities, and deceleration of spinal flexion and rotation (slows down the speed of rounding in your back and twisting). If you imagine walking, when you plant your leg to step, the hip extension and backward rotation of your opposite side torso and pelvis of the standing leg is the posterior oblique sling!
How is the posterior oblique sling affected by pregnancy?
This sling can be fairly affected by pregnancy, even though it appears that the musculature should be unaffected; after all, the belly is on the other side stretching muscles, how could our backs possibly be affected?? Well there are a ton of musculoskeletal changes that are occurring during pregnancy, and since our SI joints are huge junction in load transfer for us, it makes sense that any changes in force distribution would affect the SI joints and how we stabilize them!
First, our center of gravity shifts upwards and outwards, as the belly grows. This shift in our center of gravity can adjust where the midline of our body is, and cause us to adjust our general postural tendencies. These shifts in postural tendencies could affect the posterior pelvic joints! As the weight grows more forward, it could but extra strain on the posterior pelvic joints; a lot of uterine ligaments are attached to the sacrum, so there may be extra pulling on the SI joints as the uterus grows and grows during pregnancy.
The muscles that help to stabilize the SI joint can be affected by pregnancy, and thus decrease the stability and increase any prenatal discomfort or pain. The main muscles we will discuss are the: transverse abdominals, the pelvic floor, and the glutes.
Postural tendencies that tend to occur during pregnancy can be an anterior pelvic tilt, where the pelvis tilts forward; think poking your butt out and letting the belly hang forward. The anterior pelvic tilt can be problematic because it lengthens the transverse abdominals as the ribs and pelvis pull away from each other. When our muscles are overlengthened, they tend to become inhibited, or turn off, and weaken. This means that if the transverse abdominals, a stabilizer of the SI joint, is not working well, it could affect how we stabilize the joint and increase pain or discomfort.
If the postural tendency is the opposite, or a posterior pelvic tilt where the butt tucks underneath, it also changes the musculature balance. When we tuck our butt underneath, we tend to clench or squeeze our glutes to help us stabilize. When the glutes are clenched, they cannot move through their full range of motion and become “stuck” in this limited range that decreases their overall function. We want our muscles to be able to move through their full range of motion, because if we only strengthen in a small range, whenever we need to meet a demand outside of the range, our muscles have a higher likelihood of failing. In addition, if the glutes are clenched, it tends to also cause the pelvic floor to clench, another stabilizer of the SI joint. Lots of overactive muscles that refuse to lengthen will affect how the joint can stabilize!
Postural changes can adjust how force is distributed through our joints, and could increase or decrease the stress, particularly on the SI joint. If we can maintain a more neutral alignment, we may find that the musculature balance issues tend to alleviate.
How can you help SI joint pain during pregnancy?
We focus on strengthening the connection of the posterior oblique sling and diaphragmatic breathing. Strengthening the posterior oblique sling is done by creating exercises that focus on activating both the lat with the opposite glute simultaneously. We do this with movements that include a rowing or pulling motion and a hip extension movement.
If you want to understand how to do diaphragmatic breathing check out this breathing drill here! This will help you learn to activate the pelvic floor and transverse abdominals in order to stabilize he SI joints!
Examples would include
Glute Row Variations
We incorporate a glute bridge (either two legged, staggered stance, or single leg) with a ball squeeze (activates glutes more) and a horizontal row. We attach a band (we use the crossover symmetry but this could be done with any resistance band) above us, and row with the opposite hand of the working glute.
If my left leg was my work leg (foot flat on the floor), I would row with my right arm. If both feet were flat on the ground, I would row with either side then switch.
Focus on exhaling as you pull/bridge, and inhale as you release. Squeeze the ball on the exhale, release the ball on the inhale. Coordinating breath with movement is huge for stabilization, especially during pregnancy, and helps us to learn how to relax and strengthen the pelvic floor (big for labor).
Reverse Lunge + Row
Coordinating a lunge with a row is another way to activate the lat with the opposite glute. Row with the opposite arm as the stationary leg (work leg). Step back with the right leg, as you row with the right arm, and vice versa. Exhale as you lunge backwards with an extended arm, and then exhale as you stand up while rowing towards the torso.
Bird Dog + Row
Hold the weight in the opposite hand of the moving leg. As you exhale, extend the leg, ensuring that the hips stay stable and midline without arching in the low back. And then also row the weight towards the torso. This will activate both the glutes and lat together for the posterior chain.
As you can see, there are a number of variations that you can conduct to engage the posterior oblique sling. And there is an opportunity for creativity! As long as the movement includes some sort of rowing or pulling movement + a hip extension or single leg stability, it will utilize the posterior oblique sling.
Mobilize
There may be restriction in the musculature that supports the SI joints that is preventing the joint from moving well; so we can add in some mobility exercises to help find full range of motion in these muscles so that they function better! Our favorite exercise is the hip airplane for SI joint specific function.
Our prenatal fitness program include posterior oblique sling movements throughout to help maintain and increase pelvic stability throughout pregnancy!
And we just released our pelvic stability accessory program that compliments any workout program you are currently doing! This program is focused on increasing the strength and stability of the pelvic joints during pregnancy and the postpartum.
You can work with our pelvic floor physical therapists in person or virtually in a group setting for only $20! If you have pelvic girdle pain, you do not need to suffer! We are here to support.
References:
Brookbush, B. (n.d.). Posterior Oblique Subsystem Integration. Retrieved from https://brookbushinstitute.com/article/posterior-oblique-subsystem-pos/.
Thorell, E., Goldsmith, L., Weiss, G., & Kristiansson, P. (2015). Physical fitness, serum relaxin and duration of gestation. BMC Pregnancy and Childbirth, 15(1). doi: 10.1186/s12884-015-0607-z