If you’re postpartum and noticing stiffness through your hips, an ache in your lower back, or a niggly pain around the SI joint, you’re not imagining it and you’re definitely not alone.
I’ve been feeling this in my own body lately. When my hips start to feel stiff or restricted, I notice tension creep into my lower back, particularly around the sacroiliac (SI) joint. And once you understand the role of the SI joint, this connection makes perfect sense.
The SI joint sits between the sacrum and the pelvis. Its primary job isn’t big movement, it’s load transfer. It helps move force efficiently between the upper body and the lower body during walking, lifting, carrying, and exercise.
Because of this role, the SI joint thrives on stability with just enough mobility. Too much stiffness in the hips, and the SI joint is forced to compensate. Too much movement or poor control, and it can feel irritated and vulnerable.
Postpartum bodies go through a huge transition. Pregnancy creates ligament laxity, alters pelvic floor function, and changes how load is distributed through the pelvis and core. Add to that sleep deprivation, feeding postures, carrying a baby, and returning to training… it’s no surprise the SI joint often becomes a hot spot.
Common contributors postpartum include:
• reduced deep core and pelvic floor coordination
• stiff or under-loaded hips
• glutes not sharing load effectively
• altered pressure management
• returning to impact or lifting too quickly
The answer isn’t to avoid movement, it’s to move better.
Stretching can feel good short term, but on its own it doesn’t solve the problem. The SI joint needs to feel supported. That means pairing mobility (to free up stiff hips) with stability (to give the pelvis and spine confidence again).
This is why I’m loving a blended approach postpartum, exercises that restore movement and teach the body how to manage load again.
Below is a mix of mobility, stability, and integrated strength work that I often lean on postpartum. These are general suggestions, not a one-size-fits-all prescription, but they’re a great starting point. The list here could be endless.
While single-leg exercises are often promoted as a gold standard for pelvic and hip stability, it’s important to be cautious about when they’re reintroduced postpartum.
In the early stages of return to training, many women are still navigating reduced deep core and pelvic floor coordination, glutes not yet sharing load effectively, altered pressure management strategies and lingering lumbo-pelvic niggles from pregnancy or birth
On top of this, the hormone relaxin can continue to circulate in the body for a prolonged period postpartum, particularly in women who are breastfeeding. Relaxin reduces passive ligament support, meaning the pelvis relies more heavily on active muscular control for stability.
When that system isn’t yet doing its job well, single-leg loading can place greater demand on the SI joint and surrounding structures. Rather than improving stability, it can sometimes exacerbate symptoms or reinforce compensations.
This doesn’t mean single-leg work is “bad” or should be avoided altogether, it simply means it needs to be earned.
Rebuilding capacity often starts with:
Once those foundations are in place, single-leg strength can be layered back in progressively and with far better outcomes.
Postpartum recovery isn’t about endlessly stretching or bracing harder. It’s about finding the right balance between rehab/ prehab and ways you can layer in progressive overload.
When hips move well, the pelvis can share load more evenly. When the core and glutes re-engage properly, the SI joint doesn’t have to work overtime.
And when we respect that postpartum bodies are adapting and progress tends to come quickly and sustainably.
Ange Drake is a personal trainer, women’s empowerment coach and fitness blogger in the northern suburbs of Melbourne. She is the director of one of the few womens’ only strength training gyms in Melbourne, 23W. Ange helps women to learn how to use strength based training, nutritional strategies and a positive mindset to transform their bodies, relationship with food and mind.
