CORE: PRESENTATION TO THE ANTI-MOVEMENT EXERCISES

In the previous post, we talked about the great health benefits of having a strong and stable core. In this post we are going to deal with Stuart McGill's theory about core training based on stability rather than mobility. Traditionally, as we know, abdominal work has centered on flexions and spinal extensions, pretending to involve mostly the rectus abdominis and lumbar musculature. This work was supported by the basic theorems of bodybuilding. The greater the muscle mass, the greater the capacity to apply force. However, the core needs very different stimuli to the rest of the musculature of the human body. Therefore, the aim of core training is to stimulate the motor system by enhancing neuromuscular coordination, with the following basic objectives:

1. To create patterns of coordinated muscular coercion.
2. Be efficient in terms of intensity of activation
3. Improve response to sudden disturbances.

Movement vs. moment

First of all, we want to clarify the difference between these two terms, which are indispensable. The term flexion movement refers to the act of bending the spine forward, while flexion moment refers to the act of a moment of flexion or torque, regardless of whether there is movement. In fact, as we have seen in the previous posts with the anti-movement exercises, the aim is to increase the moment and avoid movement.

The movement with load in the spinal column whether in flexion, extension or rotation, wears down the intervertebral discs, probably producing a protrusion or hernia in the disc. In fact, there is evidence that the greater the load on the movement, and the greater the repetitions, the faster this will occur (Tampier, Drake, Callaghan, & McGill, 2007; Veres, Robertson, & Broom, 2009). Of course, we have to say that the genetics and the shape or thickness of each person's disc interferes with its durability (Scannell & McGill, 2009; Yates, Giangregorio, & McGill, 2010). The thickness of the spinal column also influences the support of loads, with wide spinal columns coming to a worse stop, since their discs have a larger diameter and consequently there is greater bending stress. In addition, the time of day also influences the possibility of herniation. In the morning, after getting up, the disc is more hydrated and supports much higher tensions in case of flexions and extensions. It is therefore not unreasonable to recommend avoiding repeated spinal flexions in the morning (Snook, Webster, McGorry, Fogleman, & McCann, 1998).

Spine and Herniated Disc by Michael Dorausch. CC BY-SA 2.0

Neutral zone

It has been known for decades that the resistance to axial compression is greater when the physiological curves of the rachis are maintained (Kapandji & Torres Lacomba, 1998), so we consider that talking about these natural physiological curves is of vital importance. These physiological curves are the ones that compose the neutrality of the rachis, and which make that the axial loads are supported in their greater anatomical efficiency. This concept of the neutral zone was introduced many years ago by Dr. Panjabi (1992), being named as the part of the range of motion within which there is minimal internal resistance to joint mobility (Panjabi, 2003). Therefore, we can affirm that the neutral zone is an ideal physiological zone of movement and control of the lumbar spine, where there is minimal stress on the passive structures, with optimal participation of the neuromuscular system. Therefore, losing control of this neutral zone in an exercise with disc load increases the risk of injury to the lumbar spine (Maduri, Pearson, & Wilson, 2008; Panjabi, 1992).

Skull and Spine by Sue Clark. CC BY 2.0

The 3 basic anti-movement patterns

Once we have seen the basic theory of the spinal column and the why of having to work it in an isometric mode (without movement) and not in a dynamic mode, we are going to propose the three motor patterns proposed by Dr. Stuart McGill. He speaks of a creation of a moment of force, that is, of absence or prevention of movement, not of its creation. Therefore, the musculature of the core, instead of pretending to generate movement, must act more as brakes than as accelerators of movement. In addition, their main function must be stabilising and not motorising.

The three mentioned patterns have as common denominator to avoid losing the neutral zone, as well as to maintain the physiological curvatures, either in a continuous and constant way, or with sudden disturbances. In the following posts we will go into detail on each of them in detail, but at least we considered it appropriate to cite them, so, according to Stuart McGill, the three basic anti-movement patterns are:

• "Anti-extension" exercises
• "Anti-lateral flexion" exercises
• "Anti-rotation" exercises

It may seem strange that "anti-flexion" exercises are not mentioned, but they are usually more focused on the work of the posterior chain like the gluteus maximus, so they are intended more for strength work than stability work.

Finally, we would like to explain a new concept in core stability, which is "abdominal bracing". This concept, also introduced by McGill, consists of a global contraction of the entire core musculature, seeking maximum central stabilization, thus providing overall stability. This co-contraction carried out simultaneously with the exercise of the core in question, will make our spine even more stable, since with the activation of the totality of the abdominal and lumbar musculature we will create a natural girdle, which will give stability to the whole. Another similar concept, although different from "bracing" is the concept of "abdominal hollowing", which has also provided high levels of activation of the deep musculature. In this, an abdominal sinking occurs, trying to bring the navel towards the spine. Although we consider it a valid maneuver, from our point of view it is focused more to inexperienced population, with lack of postural hygiene, erroneous patterns of movement and/or spinal problems.

Without further ado, see you in the next post.

May the force be with you!

References

Kapandji, I. A. (Ibrahim A., & Torres Lacomba, M. (1998). Fisiología articular : esquemas comentados de mecánica humana. Médica Panamericana.

Maduri, A., Pearson, B. L., & Wilson, S. E. (2008). Lumbar-pelvic range and coordination during lifting tasks. Journal of Electromyography and Kinesiology : Official Journal of the International Society of Electrophysiological Kinesiology, 18(5), 807–814. https://doi.org/10.1016/j.jelekin.2007.02.012

Panjabi, M. M. (1992). The stabilizing system of the spine: Part I. function, dysfunction, adaptation, and enhancement. Journal of Spinal Disorders, 5(4), 383–389. https://doi.org/10.1097/00002517-199212000-00001

Panjabi, M. M. (2003). Clinical spinal instability and low back pain. Journal of Electromyography and Kinesiology : Official Journal of the International Society of Electrophysiological Kinesiology, 13(4), 371–379. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/12832167

Scannell, J. P., & McGill, S. M. (2009). Disc Prolapse: evidence of reversal with repeated extension. Spine, 34(4), 344–350. https://doi.org/10.1097/BRS.0b013e31819712a6

Snook, S. H., Webster, B. S., McGorry, R. W., Fogleman, M. T., & McCann, K. B. (1998). The reduction of chronic nonspecitic low back pain through the control of earlt morning lumbar flexion: a randomized controlled trial. Spine.

Tampier, C., Drake, J. D. M., Callaghan, J. P., & McGill, S. M. (2007). Progressive Disc Herniation. Spine, 32(25), 2869–2874. https://doi.org/10.1097/BRS.0b013e31815b64f5

Veres, S. P., Robertson, P. A., & Broom, N. D. (2009). The Morphology of Acute Disc Herniation. Spine, 34(21), 2288–2296. https://doi.org/10.1097/BRS.0b013e3181a49d7e

Yates, J. P., Giangregorio, L., & McGill, S. M. (2010). The Influence of Intervertebral Disc Shape on the Pathway of Posterior/Posterolateral Partial Herniation. Spine, 35(7), 734–739. https://doi.org/10.1097/BRS.0b013e3181ba3a60