The link between weak glutes and Low Back Pain (LBP) has been circulating our industry for years. This has led to strengthening of the glutes as the seemingly cure-all solution in low back pain rehabilitation.
The question is:
Do weak glutes actually cause low back pain and will strengthening the glutes provide the ultimate ‘fix’?
To understand this fully, let’s first refresh our functional anatomy of the glutes:
The gluteals are made up of 3 main muscles:
- Gluteus maximus
- Gluteus medius
- Gluteus minimus
Now, what do we know about LBP?
- 70-80% of adults will experience LBP at some point in their lives (1)
- LBP is the single greatest cause of disability worldwide (12)
- While acute LBP resolves within a few weeks in most patients (15), a large majority still experience pain one year from the initial onset of symptoms (16)
For this reason, it is our job as clinicians to better understand the treatment of these cases to improve the quality of the lives of the clients we work with.
Why have so many people come to the conclusion that glute weakness specifically is a major cause of LBP?
Considering that nothing ever operates in isolation, it makes sense that we, the practitioners, have been assessing not just the site of the pain, but above and below as well for a more holistic approach. This is where the idea behind glute weakness comes in.
Biomechanically speaking, the musculature of the lumbar spine is designed to extend and laterally flex. I would also argue the primary function of the glutes is not to move but to stabilise the pelvis. However, when there is a lack of stability at any joint, we see the surrounding muscles increase in tonicity to compensate and avoid issues caused by instability (5).
With LBP, this manifests as a lack of pelvic stabilisation (aka poor glute function or weakness) in which the muscles of the lumbar spine take over as the primary stabilisers due to their insertions onto the superior aspect of the ilium (top of the pelvis). Therefore, when the low back musculature attempts to stabilise the pelvis (which is not its primary function), additional muscle fiber recruitment is required. This can increase muscle tension, tenderness and may contribute to pain; or so the thought process goes (1)(3).
There’s also the potential for excessive recruitment of the lumbar spine musculature with movements where spinal extension replaces true hip extension. Take a rounded spine in squats or an inability to hinge effectively through movements for example. This shifts forces into the low back and moves them away from the glutes, resulting in strengthening of the spinal extensors and diminishing the strength gains in the hip extensors (gluteals).
Due to these reasons, it makes sense that glute weakness could be one culprit in LBP, especially in active patients. Supporting this, the vast majority of the literature confirms that glute weakness, whether through the above proposed mechanisms or not, correlates with LBP. In chronic LBP, we see a general lack of muscle tone of surrounding areas when compared to pain-free people in the same cohort.
We know that a lack of glute strength can play a part in LBP, but what impact do other muscle groups have?
Weak glutes as a catch-all cause of LBP would be a wrongful oversimplification. There is evidence that suggests core weakness, and poor back erector endurance can also contribute to LBP(9)(14)(4). Some studies suggest specifically training the glutes is beneficial over general training for LBP(8). Others concluded that core strength over general strength was a better alternative (6), and another handful deduced it was movement but not specific training of any muscle group, that improved the pain levels of participants (7).
Based on these studies, it is hard to say with certainty that any one program or group of muscles is definitively superior to another in the treatment of LBP. However the vast majority of literature agree that some form of strength and movement training is greater than no training at all.
Is muscle weakness the only cause of LBP?
No! Anything that causes too much or too little force to go through the low back can be problematic. Not enough force and the strength to withstand loads isn’t there. Too much force (when joints like the thoracic spine or ankle aren’t mobile enough) and the low back tends to compensate and become overloaded. Throughout my clinical experience working with active clients I have seen multiple occasions where altered forces through the spine have appeared to be the determining factor of LBP.
Are there any non-biomechanical reasons for LBP?
When talking to clients, it’s clear that most LBP is variable over the course of the day and the week. This alone should give us some indication that not only weak glutes, but weak muscles in general cannot be fully to blame. Just as we cannot build strength overnight, we also cannot lose it that quickly either. Therefore, it is imperative that we address our clients holistically.
If I’m honest, in my early days as a practitioner, I thought biomechanics was the holy grail of pain and all pain could be solved by moving better and getting stronger. While I still believe there is an element of biomechanics that can be relevant to relieving pain, I’m much less dogmatic about it. I’ve come to understand that as humans, we are so multifaceted and with that comes a whole host of interdependent factors that create an individual’s experiences that we cannot ignore. Non-specific LBP is no exception.
There are a lot of things that can impact and influence someone’s LBP including but definitely not limited to glute weakness. When relevant, we should address deficits in not just strength of the glutes and core, but mobility and stability of surrounding structures that may be impacting the load demand at the low back. Additionally, as is the case with all pain, we must look holistically at psychological and social factors and assess each person as a whole. It may sound simple, but education and encouraging movement is one of the best, most researched methods of improving persistent pain. LBP is no different (7).
Build strength (not just in the glutes).