Your body is like a well-oiled machine, made up of bones, joints and muscles all working together to help you move, stay stable, and live life comfortably!
But as you age, certain parts of that machine start to wear down—especially one often-overlooked joint that plays a major role in how you move and feel every day.
Meet the sacroiliac joint, or SI joint—the small but mighty connection between your spine and pelvis.
The SI joint is responsible for absorbing shock, supporting your upper body, and keeping your hips and lower back stable as you walk, sit, stand, and bend.
But over time, wear and tear, muscle imbalances, and even prolonged sitting can lead to SI joint dysfunction, a common but frustrating cause of lower back pain and stiffness.
In fact, SI joint pain becomes more common with age due to lifestyle factors like:
✅ Joint degeneration – Natural wear and tear lead to inflammation and dysfunction.
✅ Loss of core and hip strength – Weak supporting muscles increase stress on the SI joint.
✅ Changes in mobility – A sedentary lifestyle or improper movement patterns cause stiffness and pain.
✅ Previous injuries – Old injuries or imbalances put extra strain on the joint over time.
If you’ve ever felt an aching, sharp, or burning pain in your lower back or hips, your SI joint could be the culprit.
The good news? You don’t have to live with the pain!
By improving strength, stability, and mobility, you can protect your SI joint, reduce discomfort, and keep moving with confidence!
In this blog, we’ll break down exactly what the SI joint is, why it’s so prone to issues, and share three simple exercises you can start doing today to strengthen it to prevent / get back to pain-free movement!
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What is the SI Joint?
The SI joint is located at the base of your spine, where the sacrum (triangular bone at the bottom of the spine) meets the ilium (part of the pelvis).
Unlike other joints in your body, which allow a significant range of motion, the SI joint has very limited movement; functioning primarily as a stabilizing joint.
Why is your SI joint so important?
1. Weight Distribution & Shock Absorption
The SI joint helps transfer weight from your upper body down to your legs when standing, walking, or running, which is essential for activities like grocery shopping, walking to the mailbox, or standing.
It also absorbs impact forces, reducing stress on the spine and lower extremities, whether you’re walking on hard surfaces, climbing stairs, or performing high-impact exercises like running or jumping.
When lifting kinds/grandkids, heavy objects at home or weights at the gym, the SI joint ensures that force is properly transferred through the hips and legs, preventing unnecessary strain on your lower back.
Without proper function of the SI joint, these movements—whether daily activities or weightlifting—can place added strain on your body, increasing the risk of discomfort or injury.
2. Stability
Although the SI joint allows minimal movement, it plays a critical role in keeping your pelvis and lower back stable!
This stability is essential for maintaining proper posture, especially when standing for long periods, lifting heavy objects like groceries or a laundry basket, or even tasks like bending down to tie your shoes, get up from a low chair, getting in and out of a car, or maintaining balance while walking to prevent falls.
In exercise, the SI joint helps with movements like squatting or walking on a treadmill. Without this stability, simple daily activities can feel more challenging and increase the risk of discomfort or injury.
3. Movement
While the SI joint doesn’t have a large range of motion, it allows slight tilting and rotation of the pelvis, which is necessary for walking, running, and other lower-body movements like bending down to pick up your kids or grandkids, squatting during a workout, lifting weights, or even stepping up onto a curb.
These movements may seem simple, but without the proper function of the SI joint, they can lead to discomfort or injury.
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Top Causes of SI Injury & Best Prevention Strategy
The SI joint is stabilized by strong ligaments and muscles that help maintain its function and prevent excessive movement. However, when these structures become injured or irritated, it can result in significant pain and discomfort.
Surprisingly, many SI joint injuries stem from everyday activities at home! Below, I’ve outlined the five most common causes of SI injuries plus tips to prevent each!
1. Poor Posture & Prolonged Sitting: Sitting for long periods, especially with poor posture, places unnecessary stress on the SI joint, which can lead to inflammation and pain over time.
2. Lifting Heavy Objects Improperly: Lifting without proper form—such as bending at the waist instead of using the legs—can strain the SI joint and surrounding muscles, leading to injury.
3. Repetitive Motions & Overuse: Certain activities, like running, dancing, or repetitive twisting movements, can put excessive strain on the SI joint, leading to wear and tear. While these activities can be beneficial, overdoing them can cause stress on the joint.
4. Pregnancy & Hormonal Changes: Pregnant women often experience SI joint pain due to hormonal changes that loosen the ligaments around the joint, combined with the added weight of the baby.
5. Trauma & Falls: Falls on the butt, car accidents, or sudden impacts can disrupt the alignment of the SI joint, causing dysfunction and pain, which may manifest as lower back pain, discomfort in the buttocks or hips, or stiffness in the lower back and pelvis.
What can you start doing today to prevent and / or alleviate SI injury and pain?
The best way to prevent injury and reduce discomfort is through regular strength training! Here’s why:
By strengthening the muscles around your SI joint—especially in the core, lower back, and hips—you improve stability, posture, and alignment, reducing stress on the joint during daily activities and exercise. Movements like squats, deadlifts, and planks enhance flexibility and mobility while reinforcing proper movement patterns to prevent pain and injury.
For pregnant women, strength training helps counteract the strain from hormonal changes and added weight, maintaining pelvic stability. And in cases of falls or trauma, a well-conditioned body recovers faster with greater resilience to stress.
At Results Fitness, we provide personalized, one-on-one coaching and comprehensive strength training programs tailored to target these specific muscle groups! This ensures you’re doing the right exercises, in the right form, to prevent SI joint pain and injury—during both workouts and in your everyday activities.
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The Best Exercises to Strengthen the SI Joint
The good news is that SI joint pain can often be managed and even prevented with the right exercises!
Strengthening the muscles that support the SI joint—such as the core, glutes, and lower back muscles—can help improve stability and reduce pain.
Regardless if you are working out on your own, or are an RF Warrior, here are three exercises you can do to keep your SI joint healthy and strong!
1. Glute Bridges: strengthen the gluteus maximus, which plays a key role in stabilizing the SI joint and pelvis.
How to do it:
- Lie on your back with your knees bent and feet flat on the floor, hip-width apart.
- Engage your core and squeeze your glutes as you lift your hips toward the ceiling.
- Hold for 2–3 seconds, then slowly lower back down.
- Repeat 10–15 times for 2–3 sets.
- Modification: If you want to increase difficulty, try single-leg glute bridges by lifting one leg off the ground while performing the movement.
2. Bird-Dogs: strengthens the core, lower back, and hip stabilizers, all of which support the SI joint. How to do it:
- Start on all fours with hands under shoulders and knees under hips.
- Engage your core and extend your right arm and left leg simultaneously.
- Hold for a second, then return to the starting position.
- Repeat on the other side.
- Perform 10 reps per side for 2–3 sets.
- Tip: Keep your spine neutral and avoid arching your back.
3. Clamshells: strengthen the gluteus medius, which plays a crucial role in pelvis and SI joint stability. How to do it:
- Lie on your side with knees bent and stacked on top of each other.
- Keep your feet together and lift your top knee while keeping your hips stable.
- Lower the knee back down with control.
- Repeat 10–15 times per side for 2–3 sets.
- Modification: Add a resistance band around your thighs for extra challenge.
Taking care of your SI joint with strengthening exercises, proper posture, and mindful movement can help you maintain a pain-free and active lifestyle! By incorporating SI joint-strengthening exercises like glute bridges, bird dogs, and clamshells, you can improve stability, enhance mobility, and reduce the risk of injury.
If you experience persistent SI joint pain, it’s always best to consult a healthcare professional for proper diagnosis and treatment.