Core Stabilization and Neutral Spinal Posture Part 2
Defining Neutral Spinal Posture
Neutral posture can be defined as avoiding the extremes of sustained spinal flexion (rounded spine) or extension (arched spine), or positioning the spinal column and pelvis in a manner that reflects a midposition between the extremes of these two joint actions. A total approach to abdominal and back strengthening, back wellness and functional balance training must include the concept and teaching of neutral posture. Avoiding the extremes of sustained flexion and extension, when appropriate, should be taught for both the cervical (neck) and lumbar (lower back) areas of the spine. Likewise, intentional movement that causes a shift from neutral posture is not an issue of right or wrong, but one of appropriateness as related to movement demands.
Being able to “set” or establish neutral posture when desired helps to conserve the integrity of spinal discs, ligaments and joints, as well as enhancing movement capability. Awareness of neutral posture encourages a return to, or maintenance of, proper spinal positioning during daily tasks or sport movement.
Neutral spinal posture can, in an even more simplified manner, be defined as an absence of tension in the cervical and lumbar spine. The strongest position of the spine and the position least likely to contribute to increased risk of injury or chronic degenerative spinal disease is represented by neutral posture. Neutral spinal posture refers to the maintenance of “normal” spinal curves that are inherent to a healthy, strong and properly aligned spine. See FIG. A.
Vertebral column exhibiting the normal curvatures inherent to a healthy and properly aligned spine.
It is critical to all physical movement training and back health to have mastered the skill of freely and intentionally moving from and returning to neutral spinal posture. Participants must also have the ability to maintain spinal neutral throughout an exercise or movement when appropriate.
Neutral spinal posture can be illustrated by the maintenance of proper cervical, thoracic and lumbar curvatures. See FIG. B.
Vertebrae positioning in a neutral lumbar spine.
Illustration adapted from Low Back Pain Syndrome, Rene Cailliet, M.D., F.A. Davis, 4th printing, 1991, pg. 4.
When performing any exercise, sport movement or daily task, whether seated, prone, supine, sidelying, standing and/or during movement, proper alignment in the cervical, thoracic and lumbar regions should be considered. Decisions need to be made with regard to whether or not neutral spinal posture should be maintained (i.e., during a dynamic sporting activity or when performing trunk stability exercises), or if intentionally, the exerciser should choose to move out of neutral (i.e., performing trunk flexion which is typically referred to as a trunk curl or crunch exercise).
When observing the natural spinal curves, note that the vertebrae are not stacked vertically upon one another. Yet, through the preservation of the desired or normal curvatures of the spine, this positioning protects the integrity of the spinal ligaments, joints and intervertebral discs. When the spine is neutral, the weight of the spine, gravity and other forces are equally distributed across the weight bearing surface of the discs and spinal joints, and are less likely to stress the functional units (the dynamic joints and supportive soft tissue structures) of the spine. Neutral posture minimizes compressive, shear and rotary torque forces.
Methods to Identify Neutral Lumbar Posture
In order to work with each individual's unique physical traits, it is helpful to teach the individual how to identify his/her neutral or natural (current) lumbar spinal position. Note, “natural” or “normal” is not always ideal.
One of the easiest ways to identify this starting point in the lumbar region is to stand with the heels close to or touching a wall. The protrusion of the buttocks and shoulder blades (scapulae) should lightly touch the wall. Attempt to slide one hand, palm facing the wall, between the small of the back and the wall surface. Many participants who have selfadministered this evaluation find there is no space. Some find that two or three fingers may fit in nicely. Others, who have a significantly arched back (lordosis) report that they can “drive a truck” through the existing space!
Regardless of curvature, or lack thereof, as measured by how the hand or fingers fit into the lumbar space, this becomes the reference point for returning to neutral. It should be noted that external observance by a fitness professional should be just that, an observation. Diagnostic tools provided by a medical professional should be suggested if excessive curvature or lack of curvature give cause for concern. There is no “perfect” amount of curvature, nor is it within the scopeofpractice of most fitness professionals to try and attempt to ascertain whether a specific spinal curvature is desired, or represents an unhealthy situation.
Another method that can be used to identify neutral posture is to slowly rotate the pelvis into an anterior tilt (arching the low back) and then slowly rotate the pelvis into a posterior tilt (flattening the low back). Find a neutral point that represents a position between the two extremes. This method can effectively be used by placing the individual in a hands and knees position on the floor, a standing position with a slight bend in the knees and hips, or by positioning him/her in a seated position on a stability ball.
Trunk Flexion and Extension
Early anatomy books illustrate that either excessive extension or flexion of the lumbar spine result in disproportionate and unequal stress on the discs located between the vertebrae. Over time such stress could result in herniated discs, and resultant swelling, nerve root irritation or impingement, and/or degeneration of the vertebrae. Sustaining a misalignment like this during dynamic movement or throughout the day (sitting with a rounded back), may cause irreparable and cumulative damage that can lead to pain, injury and a loss of painfree mobility in the low back region.
Vertebral or spinal flexion is characterized by compression to the anterior aspect of the disc. Spinal flexion occurs when performing traditional abdominal “curls” where the rib is drawn toward the pelvis, or when a person sits with a rounded low back at his desk. Posterior ligaments, the muscle sheath, and other soft tissue limit excessive flexion. See FIG. C. Spinal extension is restricted by mechanical impact of the
facet joints and by the anterior longitudinal ligament. See FIG. D.
Illustrations adapted from Low Back Pain Syndrome, Rene Cailliet, M.D., F.A. Davis, 4th printing, 1991, pg. 90.
When neutral alignment of the lumbar spine is maintained, the forces on the discs between the vertebrae are greatly reduced, as well as stretch forces to stabilizing spinal ligaments. Neutral posture more evenly spreads compression, shear or torque forces over the load bearing surfaces of the intervertebral discs. This helps avoid a concentration of high stress forces in small areas of the discs.
Neutral Posture Summary
In an extensive review, Plowman (1992) highlights the importance of neutral spinal posture in the lumbar region. Greater posterior tilt (toward flat back position) increases low back muscle and ligament tension and, as a result, compressive forces on the spine and discs. It is reasonable to conclude that a sustained flexed or flat back position inherits many of the same risks that a sustained extended or excessively arched back does. Specifically, the ligaments, muscles, fascia and discs that make up the spinal column are put at risk for chronic, degenerative processes to occur.
It must be emphasized that the back was meant to flex as well as extend, and was meant to laterally flex and rotate. Keep in mind that one cannot perform effective, full range movertype (or isolation) trunk exercises without flexing or extending the spine. Nor can a person effectively participate in all athletic or daily movement requirements unless he/she can move into, and out of, neutral posture. On the other hand, an individual should know how, for example, to establish and preserve neutral posture if he/she is sitting at a desk, driving a car, riding a stationary bike or walking.
Flexion and extension are well tolerated by the spine and its associated soft tissues, including the spinal discs. In fact, this type of movement is necessary, for example, to achieve disc nutrition. Dynamic movement would not be possible if the spine did not tolerate this type of movement. However, excessive and uncontrolled (ballistic) movement of the spine, as well as rotation that is combined with a poorly aligned spine can be detrimental. Remember that the devastating nature of back pain is not associated with a “lightening strike.” Instead, a habit that is characterized as seemingly innocuous, such as sustaining poor seated posture over long periods of time, is a leading contributor to low back pain and the associated discomfort or disability.
Material in this chapter adapted from Douglas S. Brooks' live workshop presentations and The Complete Book of Balance Training (in press), by Gregory Anderson, Douglas Brooks and Peter Twist, Effective Strength Training by Douglas S. Brooks, 2001 and BOSU Integrated Balance Training, Brooks and Brooks, 2002.