PT on the Net Research

Before the Core - Part 1

As the words "core" and "function" have taken center stage in the arenas of health, fitness and strength and conditioning. Many professionals are making the terms mutually exclusive. In other words, they are using both words to mean the same thing. Is core training and functional training one in the same? The answer is "no."

Core training and stabilization is agreed upon by most authors and researches to refer to the lumbo-pelvic complex and spinal stabilization. Functional training refers to training the body to optimally perform "real world" movements involving acceleration, deceleration and stabilization, using biomechanically efficient and coordinated movements.

The critical differentiation to make here is that a complete functional training progression must include core training and stabilization. However, core training and stabilization do not always equate to complete "functional training." In fact, many exercises that have been labeled as "core strengthening" exercises can contribute to perpetuating an individual's existing dysfunction.

By dysfunction, I am referring to existing muscular imbalances and altered sensory perception that create faulty movement patterns. It is often not the exercise that is at fault but rather the execution of the exercise by the individual. This can occur when an individual is placed in a position or positions that require static or dynamic stabilization utilizing the core musculature. During this stabilization, the strategy that their motor system uses may be biomechanically inappropriate. The individual in this case will resort to their unique position of strength. For example, the person in Figure 1 is keeping a neutral spine and eccentrically loading their abdominals to avoid excessive lumbar extension. Figure 2 depicts the same individual demonstrating a stabilization strategy for someone with weak lower abdominals and tight hip flexors. Notice how the individual in Figure 2 flexes through their middle thoracic back. They have sought to stabilize themselves using the superficial upper rectus abdominus, pecs and abducting their scapulae. The flexion in their thoracic spine is their strategy to indirectly minimize excessive lordosis in the lumbar spine in this position.

Figure 1
Figure 2

A movement strategy occurs high up the decision making process of planning a movement. According to Massion, strategy implies the existence of a choice in attaining the movement goal. Therefore there is some cognitive input by the individual and the response is not purely reflexive - happening below the cortical level.

A strategy is created when a movement synergy or synergies is repeated enough times that it is learned. A movement synergy is a coordinated pattern of muscle activity that produces force, reduces force or stabilizes against force.

The individual in Figure 2 will eventually become more stable on the ball using this kyphotic positioning. His balance will improve using this strategy but this balance will come at the expense of the biomechanics of his shoulder girdle. As he further trains his core in this manner without correction of the substitution patterns, he will develop what Kibler calls a sub-clinical adaptation complex. The adaptation is the use of a compensatory mechanism utilizing thoracic flexion for indirect lumbar stability. It is categorized as sub-clinical because there is no pathology present – yet. However, it is only a matter of time before this individual exhausts his body's ability to compensate and pathology will be present.

Why would someone use an inappropriate strategy when you, as a professional have clearly explained and demonstrated the desired outcome? Hanna refers to this as "Sensory Motor Amnesia." He describes this as a condition in which a person's ability to voluntarily contract or relax a muscle(s) is directly dependent on the degree to which a muscle can be sensed or felt. Therefore, our peripheral output (the way we move) is directly dependent on the quality of our proprioceptive input. Computer programmers have a saying for bad software: Garbage in equals garbage out. If the code (proprioceptive input) you place in your software isn't accurate, your program (your movement) will crash.

Another contributing factor to this thoracic flexion example is that tight muscles have a low irritability threshold. They will become active or overactive during instances when they are not the prime movers. Janda did a study in which subjects with lower back pain were given abdominal curl up exercises. EMG recordings of the lower back erectors showed that these lower back muscles actually fired prior to the abdominals at the initiation of the curl up. Does this imply that the subjects' lower back musculature contributed to lumbar flexion? Absolutely not. Instead it demonstrated the low irritability threshold of this muscle group. The individual who is represented by the example in Figure 2 would likely be tight through the muscles of the chest and anterior shoulder. With the upper extremities placed in a weight bearing position, these muscles immediately became the dominant stabilizers.

You may repeatedly tell your client to engage the abdominals and allow the thoracic spine to passively drop into extension and they can't. They might be able to do one or the other but not both. And they certainly can not do this on an unstable apparatus.

Prior to putting your client in the position of Figure 1, use a modification of the exercise (i.e., Prone Plank on Knees, Elbows on SB). This exercise reduces the overall demand on the body by shortening the body as a lever. In addition, the gravitational vector pulling the pelvis into an anterior tilt is lessened. With the elbows flexed on the ball the individual’s use of the biceps for stabilization is minimized. This improves their ability to extend the thoracic spine and reduce the tendency toward scapular abduction.

What happened in Figure 2 can in fact happen with any exercise or any movement. But because of the way the industry has gravitated toward core training, it is very important for health and fitness professionals to understand that that the application of an exercise categorized as addressing the “core” does not give one cart blanche to use it with anyone anywhere at anytime.

I am continually asked by professionals at my seminars about this stabilization exercise or that stabilization exercise. It is usually a "sexy" new exercise that they saw at a workshop or in a magazine. And my first question is: "For who?" And my second question is: "For what?"

Responding with a question is my attempt to have the individual realize the uniqueness of each and every one of his or her clients. And the only way to differentiate uniqueness is to assess. A simple postural screening can provide a wealth of information to begin the assessment process. This combined with extensive health history is an excellent starting point. Of course, what you do with the information gathered is what really counts.

In Part 2, I will expand on the need for using corrective exercises for all of your clients, regardless of their current level of musculoskeletal health.