If you’ve been struggling with pain around your low back, buttock, or pelvis, you may have heard someone mention your sacroiliac (SI) joint. SI joint dysfunction is a common cause of pelvic and low back pain, yet it is often misunderstood or mistaken for a herniated disc, sciatica, or hip problem.
Many people notice their pain seems to flare up with certain activities but aren’t sure why.
The good news? Understanding what aggravates SI joint pain is often the first step toward managing it. Even better, many people with SI joint pain improve significantly with pelvic floor physical therapy that addresses the entire lumbopelvic system—not just the painful joint itself.
At Legacy Physical Therapy, we help patients throughout the St. Louis area identify the underlying causes of SI joint pain and develop individualized treatment plans that restore stability, improve movement, and reduce pain.
What Is the SI Joint?
The sacroiliac joints connect the sacrum (the triangular bone at the base of your spine) to the ilium bones of your pelvis.
You have one SI joint on each side of your pelvis.
Although these joints only move a few degrees, they play an important role in:
- Transferring forces between your legs and spine
- Absorbing shock during walking and running
- Providing stability during lifting and movement
- Supporting your pelvis during pregnancy and postpartum recovery
When these joints become irritated or unstable, everyday activities can become surprisingly painful.
Where Is SI Joint Pain Felt?
SI joint pain commonly occurs:
- On one side of the low back
- Deep in the buttock
- Around the dimples at the base of the spine
- Into the hip
- Into the groin
- Occasionally down the back of the thigh
Many patients point with one finger directly over the SI joint.
Unlike true sciatica, SI joint pain usually doesn’t travel below the knee, although some people can experience symptoms that feel similar.
What Aggravates SI Joint Pain?
Several activities place additional stress on the SI joints.
1. Standing on One Leg
Any activity where your weight shifts primarily to one side can increase stress on the SI joint.
Examples include:
- Standing while brushing your teeth
- Holding a baby on one hip
- Resting your weight on one leg while talking
- Putting on pants
These positions force one side of the pelvis to stabilize the entire body.
2. Walking Long Distances
Walking requires constant force transfer through the SI joints.
If the muscles that support the pelvis aren’t working efficiently, prolonged walking may increase pain.
Many patients report:
- Pain after neighborhood walks
- Increased discomfort during vacations
- Pain that worsens as the walk continues
3. Climbing Stairs
Each step places significant load through one side of the pelvis.
Going upstairs often hurts more than going down because of the increased demand on the hip and pelvic stabilizers.
4. Rolling Over in Bed
Rolling from one side to the other creates rotational forces through the pelvis.
This is one of the classic complaints we hear in the clinic.
Patients often describe: “The pain wakes me up every time I roll over.”
5. Getting In and Out of the Car
Twisting while moving both legs into or out of the vehicle combines rotation and weight shifting—two common aggravating factors.
6. Running and High-Impact Exercise
Running increases repetitive loading through the pelvis.
Jumping, box jumps, and high-impact workouts may also flare symptoms, especially if pelvic stability is lacking.
7. Heavy Lifting
Improper lifting mechanics increase forces across the pelvis.
This includes:
- Lifting children
- Carrying groceries
- Moving furniture
- Deadlifting
- Gardening
The issue often isn’t the lift itself—but rather how well your body distributes the load.
8. Sitting Too Long
Although SI pain is often associated with movement, prolonged sitting can also aggravate symptoms.
Sustained pressure can irritate surrounding tissues and stiffen the joints.
Many people notice increased pain when they first stand up after sitting.
9. Pregnancy
Pregnancy is one of the most common causes of SI joint pain.
Hormonal changes increase ligament laxity while your growing baby changes your posture and center of gravity.
These normal changes increase stress on the pelvis.
10. Postpartum Recovery
After delivery, the ligaments remain more flexible for several months.
Combined with:
- Weak abdominal muscles
- Pelvic floor dysfunction
- Carrying your baby
- Sleep deprivation
- Repetitive lifting
…the SI joints may become irritated.
The Pelvic Floor Connection
Many people are surprised to learn that pelvic floor dysfunction and SI joint pain often occur together.
The pelvic floor is part of your body’s deep core system, working alongside:
- The diaphragm
- Deep abdominal muscles (transversus abdominis)
- Multifidus muscles in the spine
- Gluteal muscles
- Hip muscles
Together, these muscles provide dynamic stability for the pelvis.
When one part of the system isn’t functioning well, the SI joints may absorb more stress than they were designed to handle.
Can Tight Pelvic Floor Muscles Cause SI Joint Pain?
Yes.
An overactive or tight pelvic floor can:
- Increase tension throughout the pelvis
- Limit normal movement
- Contribute to muscle imbalances
- Increase pain sensitivity
- Affect how your pelvis transfers load
Some patients need strengthening.
Others actually need relaxation, breathing retraining, and improved coordination.
This is why an individualized evaluation is so important.
Why the SI Joint May Not Be the Real Problem
Many people assume the painful joint is the root cause.
In reality, SI joint pain often develops because something else isn’t functioning optimally.
Common contributing factors include:
- Weak gluteal muscles
- Poor core coordination
- Hip mobility limitations
- Scar tissue from previous surgeries
- Pregnancy or postpartum changes
- Poor breathing mechanics
- Pelvic floor dysfunction
- Asymmetrical movement patterns
How Pelvic Floor Physical Therapy Helps SI Joint Pain
At Legacy Physical Therapy, we look beyond the painful joint.
A comprehensive evaluation may include:
Movement Assessment
We analyze:
- Walking
- Squatting
- Single-leg balance
- Functional movements
- Posture
Pelvic Floor Evaluation
When appropriate, we assess whether the pelvic floor is:
- Weak
- Tight
- Uncoordinated
- Contributing to pelvic instability
Core Assessment
We examine how your:
- Deep abdominal muscles
- Diaphragm
- Back muscles
- Pelvic floor
work together during movement.
Core Assessment
Treatment may include:
- Manual therapy
- Joint mobilization
- Soft tissue treatment
- Myofascial release
- Dry needling (when appropriate)
- Cupping
- Scar tissue mobilization
Exercise Prescription
Your program may include:
- Core coordination exercises
- Glute strengthening
- Hip stabilization
- Balance training
- Functional lifting strategies
- Breathing exercises
The goal isn’t simply to strengthen muscles—it’s to improve how they work together to support your pelvis.
When Should You See a Pelvic Floor Physical Therapist?
Consider scheduling an evaluation if you have:
- Pain near your SI joint lasting more than a few weeks
- Pain when walking, rolling over in bed, or climbing stairs
- SI pain during pregnancy or after childbirth
- Pain that returns despite chiropractic care or injections
- SI joint pain along with urinary leakage, pelvic pain, or pain during intimacy
These symptoms often indicate that your pelvic floor and core deserve closer evaluation. Schedule a FREE phone call with a PT to see how we can help you!
