For some the jury is still not out on whether one should or should not engage the gluteus maximus muscle when performing back bending yoga postures. The key movement of the pelvic girdle when doing any back bending posture is nutation of the sacrum. Tilting the pelvis forward to encourage sacral nutation for many seems paradoxical, however, this is imperative to bring ease and harmonious extension along the entire length of the spine – the crux of back bending! You only need take note of the stance of young gymnasts before they effortlessly flip back into a back bend – pelvis tipped forward, butt out, chest open and lifted with maximum length and arch in their spine. As the sacrum is the base of the spine, its position greatly influences the rest of our spine and all that attaches to it. Nutating the sacrum uncoils the spine and naturally enables the ribcage to flower open. Without this position back bending is stumped, difficult and potentially painful. With the pelvis anteriorly tilted and the sacrum nutated engagement of gluteus maximum complements backbends by producing maximum extension at the hip joint. To understand sacral nutation and its far-reaching effects please refer to my previous article (a free download) ‘Sacral Nutation, the Key to Straight Feet in Backbends’.
Back to gluteus maximus, commonly referred to as glute max. Firstly, let’s have a look at the functional anatomy of this muscle. Glute max is the superficial ‘rump’ muscle of our buttocks. Its prominent, characteristic shape and large size correlate to its powerful role of maintaining our trunk in an upright position. Additionally, gluteus maximus plays an essential role in gait, i.e. walking. When we walk it is glute max that provides the power to propel us forward as well as take the leg back ready for the next stride. Its main action is extension or hyperextension of the hip joint, which is the action used in back bending. Additionally, glute max externally rotates the thighbone or femur.
There are many other buttock and leg muscles that contribute to hip extension, however, this is not their main action and at this point will only confuse the issue. However, the only other major muscle that is dedicated to hip extension is the hamstrings muscle group. Three of the four hamstrings are bi-articulate, which means they cross and therefore act upon two joints. The other joint that the hamstrings act upon is the knee joint where they perform knee flexion. This means that, especially when the knees are bent and the hamstrings are already shortened, they become less effective at hip extension. This happens in many of the back bends we perform: Ustrasana (Camel posture), Dhanurasana and Urdhva Dhanurasana (Bow and Upward Facing Bow) and any other back bend with our knees bent. If you visualize the position of the hamstring muscles and their attachment on the ischial tuberosities (sit bones) you can see that they actually attach below the hip joint. This of course gives them a mechanical disadvantage to perform hip joint extension. On the other hand, gluteus maximus being a single-joint muscle is very effective at hip extension. It spans across the very centre of the hip joint and is very effective in back bends whether our knees are bent or straight. Its main purpose is extension of the hip joint.
This begs the question, if we do not use the gluteus maximus muscle to extend our hips in back bends which muscle(s) will we use? There are two easy to define choices. The first is that we can use the hamstrings. As explained, the hamstrings are less effective at hip extension especially when our knees are bent. The other choice is to use the spinal extensor muscles. These include the superficial erector spinae, the semispinalis and the deeper quadratus lumborum (QL) muscle in the low back. Note that these muscles cannot contribute to hip joint extension as their function is extension of the lumbar spine or low back. Obviously, lumbar spine extension happens whilst performing a back bend but over activity of the lumbar extensor muscles causes excessive movement and compression of the vertebral facet joints, which join one vertebra to the next. Over-activation of the lumbar spinal muscles can lead to jamming of these facet joints (Facet Syndrome) with its associated muscle strain, spasm and pain. Using glute max in back bends keeps the primary fulcrum or axis of the back bend at the hip joint instead of in the low back. This prevents low back hypermobility and especially end-range loading of the facet joints of the lumbar spine.
Dr Vladimir Janda, known as the ‘Master of Rehabilitation’, noted that certain muscles tend to be inhibited (have less tone), while others tend to be hyperactive or facilitated. An inhibited muscle is different to a weak muscle in that it may be inherently strong but other factors such as trauma, misalignment, muscle imbalance, underuse, overuse or any other stress may handicap it and prevent it from functioning optimally. Inhibition of a muscle implies a deficit in neurological input. Glute max is a muscle that tends to be inhibited, whereas the QL in the low back can become facilitated. Over use of the low back extensor muscles can make one susceptible to developing Facet Syndrome when practicing back bending postures.
With our lifestyles that require dominant sitting poor glute max is constantly sat on, flattened and consequently switches off! The common pattern is an inhibited and/or weak glute max with shortened hip flexors. Muscles work in pairs with one opposing the action of the other. This means that engaging the hip extensor muscles causes the hip flexor muscles (those in the front of the hip joint) to lengthen in the neurological process known as reciprocal inhibition. The hip flexors are the very muscles we are trying to stretch and lengthen to improve our back bends. As the very efficient and often overlooked hip flexor iliacus also tends toward facilitation, this helps to ‘switch off’ this already over used, often tight muscle. Engaging glute max in back bends enables us to harmoniously achieve the length required of our hip flexors whilst effectively extending the hip joint.
In part two we will look at why students sometimes choose to not use their glute max doing backbends, although this is less ‘natural’ and takes more concentration. We’ll also examine the importance of sequencing to enable us to perform our backbends with ease and grace.
Click here for part 2 of this article.