The Quadratus Lumborum
The quadratus lumborum or 'QL' is the deepest abdominal muscle and commonly referred to as a back muscle. The ‘QL’ wraps around the lumbar spine and stabilises it. Often ignored in a basic stretch routine, stretching and activating this muscle will ensure that your spine has it's freedom to function fully and is not being restricted.
On its own, the function of the 'QL' is to laterally flex the spine, or bend sideways (McGill, 2012). When working alongside other muscles, the QL stabilises the lumbar spine on each side (Nickelston, 2016) much like the cable stays of a bridge. The QL also maintains posture (Marieb, 2015). To visualise the work of the QL, think about holding a heavy object (heavy bag, suitcase, kettlebell etc) in your right hand and nothing in the left. It’s the QL muscle on your left side that is contracting/working to help stabilise the spine and keep you upright. Without this muscles resistance, the weight would bend you to the right side. The QL doesn't change shape as it contracts to stabilise you. This particular type of contraction is know as isometric. The QL is also the first muscle to combat the buckling feeling of the spine when the spine is overloaded. Think of a heavy squat, if the load (the weight) starts to put undue pressure on the spine, the first line of defence is your QL (McGill, 2016).
Looking at the above image of the QL, it 'works' to support you as you bend backwards in your various poses and it would appear as though it could restrict your forward fold poses if this muscle is too tight. In most cases I have observed, tightness is always on one side.
To give you a yoga example of what the QL does when it isn't stabilising the spine, think about Gate Pose (below). This is a side or lateral bend of the spine. Looking at the image below, my right side QL contracts/tightens to bend me to the right side creating a stretch into my left QL. When I come out of the pose my left QL (with other muscles of course) will now contract/tighten to pull me me back to centre.
The yoga example of using the QL to assist and stabilise the spine is seen in Dhanurasana (bow pose). Here the QL will assist and stabilise to extend the spine (Kiel 2013). Experiencing tightness in this muscle will inhibit your back bending as tightness will pull on the lower spine restricting your movement. In the image below I am practicing my wheel/back bend. The principle is the same as Dhanurasana. The QL either side of my spine is working to stabilise me.
Insertion & Origin.
The QL originates at the Iliac Crest (Specifically the top and back part of the pelvis. This bone of the pelvis is specifically known as the Ilium). The QL then goes and inserts itself to the boney parts that stick out to the side of each of the vertebrae, the transverse processes and also onto the last and 12th Rib, the floating rib (Grays Anatomy, 1918).
I myself struggle with tightness and weakness at this muscles and this is a constant irritation which exacerbates my already fragile lower back. Stretching this deep core muscle may not cure what for me is a chronic condition (I have had a bad back for 20 years), but will help in assisting my other "core" muscles in my core stability. The theory being that any lumbar spine pathologies like bulging discs create chronic inflammation that may effect nerve conduction and response to the QL that can result in poor muscle stabilisation. Effectively increasing your chances of having "a bad back".
What is core stability again?
Spinal biomechanist, Dr Stuart McGill (2001, 2002), describes core stability as, “the ability to maintain your posture and balance while moving your extremities."
The stability of the "core" is crucial in providing a foundation for movement of upper and lower extremities, help support loads, and protect the spinal cord and nerve roots (Panjabi, 1992), if the QL is weak or tight, the core reaches out to distant regions of the body to pick up the slack. This can result in improper function and for some, pain.
Since the QL works to maintain correct posture of the spinal column and pelvis, it works extra hard when a person sits with improper posture. This constant effort by the QL to maintain correct positioning of the spine and pelvis can lead to the muscle becoming overworked, irritated, and painful. In a study in 2016, QL strength was assessed amongst 20 athletes. All had one side of the QL working harder than the other. This creates an imbalance within the body often leading to additional postural problems and even pain.
How to assess if you have tight or a weak QL.
To test for flexibility you can do a number of yoga side bends and assess your movement. Can you go further/deeper on one side? Do you feel restricted in general? Again this is not a perfect test and I don't believe there is such a thing but this will give you a general idea. Below Lindsay Brown one of our teachers demonstrates yoga poses that would theoretically stretch the QL.
Image 1 below - Standing triangle pose (Satchidananda, 1970).
Image 2 - Bikram side bend (Rockefeller, 2015).
Image 3 - Gate pose (Vishvetu, 2015).
Image 4 - Revolved Head-to-Knee (Lacerda, 2015)
Image 5 below - A simple side bend from seated/sukhasana (Lacerda, 2015)
In the poses shown above, you are looking to hold the poses for a few breaths and attempt to establish if you feel restriction in your QL. If you do, I would personally start with the seated bends and work up. Start with the seated bend in sukhasana (Image 5), hold for anything from 30-60 seconds each side. Do this more than a few times per week if you can.
It is very hard to test for strength as strength is always relative so I have found its best to look for imbalance more than anything else. So is my right QL is tighter or weaker than the left (and vice-versa). This also continues the Hatha Yoga principle of Sun and Moon or balancing opposites. Here we look for the right and left sides of the spine to do equal work so the spine is uninnterupted and not being pulled in either direction.
To test for strength you can do a simple side plank as demonstrated below. This is by no means a perfect test but does start to give you some idea if any issues. Perform a side plank for 20 seconds on one side and then 20 seconds on the other side. Compare strength of the plank by side. If there is pain during the assessment, you already know there is dysfunction (so see your doctor). Again this is not a perfect test (nothing really is) but will give you some idea of wether you have one QL side weaker than the other. If you can hold the side plank on both sides for 20 seconds plus without any problems, slowly increase your times on each side. If you cant hold for 20 seconds then make this your goal. This exercise emphasises the endurance of the QL, which is generally the main goal in strengthening low back and core stabilisers.
Lying on your left side, prop yourself up on your left foreram. Extend your legs and keep your feet together. Make sure your left elbow is directly under your shoulder. 2 - Engage your abdominals and push downwards through your left arm to raise the hips off the floor. Breathe slowly (British Medical Association, Bad Back Book, 2013).
The side plank is a great workout for the QL that is closer to the floor as well as the obliques on the same side. Research shows that they experience similar levels of activation (McGill, 2016).
After my plank I then progress onto a more dynamic side plank. This like the static version also works other core muscles too. My focus whilst in the dynamic version is solely on my QL. I want my QL to integrate with the rest of my core to create core stability. In the video below I start my basic side plank. After having complete each side I then move on to my dynamic plank and aim for 60 seconds.
From the basic side plank, position yourself so that your left forearm in in contact with the ground. Your right foot should be in front of your left. The hips are "stacked" meaning that are on top of one another. The core is "braced". From this side plank come into a basic plank keeping your core stiff and your spine long. Then shift straight into a side plank on your right arm. Try not to drop the hips as you do so. Keep your hips up and don't lose the stiffness in your core. Aim for 60 seconds with good form. If this is too difficult, revert back to the basic side plank.
I then progress, in time, to what is my favourite QL exercise (video below). I "brace" my core and perform a single arm overhead press. What appears to be a shoulder strengthening exercise is actually a great way to challenge your QL's ability to stabilise your spine.
At first I could only manage 8 repetitions on my left side compared to 20 on my right. That is a huge difference. Over time I have managed to balance these numbers out. So now in theory, my QL is working alongside the rest of core to help stabilise me in my backbends and any other pose that requires me to engage my "corset".
Bracing my core, I lift the weight (in this case a kettlebell) overhead. As you can see from the video, there is no movement anywhere in my body except at my shoulder and elbow joint. If my spine loses its straight line, I am losing my technique. The spine should remain straight and the stomach/abdominals/corset braced and engaged. Again.....there should be no movement except at the shoulder and elbow joint.
In summary, strength is required in in your QL so that your QL can bear the burden of its role in core stability. There is evidence that suggests if there are limitations in your spine's ability to backbend, then the QL has to work overtime to support your spine. In the event your QL is weak then there is the high probability of dysfunction and pain. So strengthen your QL and don't forget to stretch it too. You should see your doctor if you are suffering with back pain of course, I am not saying this is down to your QL. But if you have been told by a practitioner or therapist that the problem with your back may well be your QL, the videos and images above will hopefully help you with your rehabilitation.
If you have any questions about your own back pain please feel free to contact me.
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