Let's continue our stabilization series with an article on low-load training of the global stabilizers. I suggest you read my first article, "Core Stabilization Principles,"1 as background.
I don't think adjustments (no matter how perfectly targeted) and/or soft-tissue work are enough to solve chronic pain patterns. I don't think laser, microcurrent, decompression, etc., are enough to solve chronic pain. I love all of these tools, and they do affect muscular function, but they are not enough. Chronic pain has a critical motor-control component. The patient needs to learn to use their body differently. If you become a rehab-oriented chiropractor, you will reach a whole different population of patients. You won't have as many "fix me" patients draining your energy. You'll have more patients who will fully engage in their own healing process.
Global Stabilizer Muscles and Their Function
What are the global stabilizers?"2,3 These are the "outer" core muscles. They are the only joint stabilizers whose main role is to control direction-specific stress and strain. They include the more superficial multifidi, the lateral QL fibers, the oblique abs, the anterior psoas and all of the gluteals. These are the larger postural muscles of the core.
Table 1: Core Stability Overview
| Symmetrical Strengthening (Limb) | "Core" Trunk Strengthening | "Motor-Control" Stability: Global | "Motor-Control" Stability: Local | |
| Training Threshold | high | high | threshold | low |
| Muscle Bias | global mobilizers | global stabilizers | global stabilizers | local stabilizers |
| Position/Plane of 10 Loading | flex-ext plane +/- SB / ab-ad Rot eliminated | neutral position +/- rot plane Rot challenge | rot plane +/- neutral position 3 D | neutral position No D |
| Type of Loading | isotonic (conc) +/- isometric & isokinetic | isometric +/- isotonic (concentric) | isotonic (eccentric) & isometric | isometric |
Global stabilizers have three primary functions: first, to concentrically shorten through full available range; second, to isometrically hold inner range (shortened) positions; and third, to eccentrically control the return to neutral. They must be able to do all of these with efficient slow motor-unit recruitment. If you understand and know how to train all of the above, you are way ahead in your rehab understanding. I'll try to explain these concepts in the rest of this article. I've included a table outlining the way this model looks at the various muscles of the body.4 [Please see Table 1 and Table 2.]
Specific movement dysfunctions develop from states of pain, tissue pathology or patterns of habitual misuse. This observation was one of the genius concepts from Vladimir Janda and has been validated via research. The patient loses the ability to perform the three functions of the global stabilizers listed above.This is significant both for treatment/rehab of painful conditions and for prevention of recurrence. The primary indication for needing/doing global stability training is a recurrence of movement related pain or direction-specific stress or strain. The classic examples are the patients who always seem to get worse when brushing their teeth, loading dishes, gardening, etc. A common theme here is flexion-related stress and/or flexion that hurts, but is relieved by extension. Global stabilizers are also critical to control extension and rotation, but this article will focus on the most common deficit: lack of control of flexion.
Slow, Low-Load Recruitment
Why low load? To understand this, first let go of the word strength. Strength and low-load stability are totally different physiological concepts. Stability is referring to recruitment efficiency, while strength is referring to the ability to produce force. In low-load exercise, we are training for low-threshold recruitment and motor-control training, rather than hypertrophy or strength. To accomplish this requires nonfunctional training that takes the person out of their normal motor habits. We will have the patient move one joint system while maintaining neutral position in an adjacent joint system. Coordinating this type of movement is the basis for both testing of global motor control and for global stability exercises.
Table 2: Training Principles for Core Stability
| Symmetrical "Traditional" Limb Strengthening | "Core" Trunk Strengthening | "Motor-Control" Stability: Global | "Motor-Control" Stability: Local | |
| Guidelines for Training | fatiguing high-load exercise | fatiguing high-load exercise | no-fatigue low- load exercise | no-fatigue low- load exercise |
| +/- speed | +/- speed | asymmetrical limb or trunk load | trunk stays in neutral | |
| symmetrical limb load | asymmetrical limb or trunk load | Maintain trunk neutral | only slight global muscle activity | |
| limb or trunk lifting in the flexion-extension plane | resist rotation force at trunk | emphasize rotation control at trunk and girdles +/- flex-ext control | discourage core "rigidity" | |
| No rotation | rotate against resistance | Short-range hold for postural control | ||
| global mobilizer dominance | discourage global mobilizer dominance | |||
| encourage core "rigidity" | ||||
| Reproduced with permission from Kinetic Control International. | ||||
Low-load exercise is defined as an exercise the patient can do for four minutes without fatigueor substitutions. We are attempting to retrain and recruit the slow postural muscles that we use to stand, sit and accomplish simple activities of daily living. By going slow and doing sustained activities, we are primarily recruiting the slow-motor units - the postural and tonic motor units within the muscles. The movements must be done with slow, continual movements void of substitutions by other muscle groups, must not have a respiratory cost (breath holding), and must be done in the low-threshold environment.
These types of exercises will optimize postural control and stability. So, what day-to-day activities or exercises enhance global stabilizers? Ballroom dancing, yoga, Feldenkrais, tai qi or qigong come to mind.
Once we add a higher load (weights, machines, etc.) or more speed, we are primarily utilizing the fast-motor units. This recruits the bigger mobilizer muscles and the fast-motor units within the stabilizer muscles. For global-stabilizer training, we are not trying to change muscle structure. What we are attempting to do is improve the nervous system's ability to coordinate and improve efficiency. Sounds like a chiropractic principle to me!
Low-load exercises are mentally challenging. First, it's hard to get "athletes" to slow down. Second, when proprioception is diminished, the sense of effort increases during low-load exercises. The principles for both testing and training are fairly simple. Can these patients control direction-related stress and strain? Our example will be testing for lack of global-extensor function for patients who fail to control flexion. We are testing and/or recruiting primarily the global multifidi. Have the patient flex below the lumbar spine and see if they can maintain the lordosis and hold neutral in the lumbar spine. Examples of this include "the waiter's bow" (have the patient bend forward, while maintaining lumbar neutral) and the hip hinge (stand to sit and sit to stand). Craig Liebenson has a nice handout on the hip hinge on his Web site.5 The test assessment is simple: Can the patient maintain neutral lumbar spine as they do these isolation motions. Watch closely from the side.
Another test, done supine hook-lying, is to have the patient lift either one bent leg at a time to 90 degrees, or lift both bent legs. Can the patient maintain the lumbars in lordosis? You can test with a flat hand under the spine. Ideally, put a pressure biofeedback stabilizer unit (or blood pressure cuff) under the lumbars to give the patient visual feedback. Can they maintain a 40-pound pressure? It's OK if the pressure goes up two pounds with one leg lift or up to 10 pounds with the double leg lift.
These same motions can be used as the retraining exercises. I like the ease of these motions. They are not hard for the patient to learn and can really make a difference. The hip hinge is both an exercise and an integration into a functional activity, going from sit to stand. The exercises have to be done with attention to detail, specifically keeping the lumbar spine in neutral and not letting the lumbars flexwhile moving at the hips. Keeping the hips in neutral, rather than letting the knees fall outward or inward, is also important.
A brief clinical note: I re-injured my low back two weeks ago, and I kept having morning glitches, little spasms and catches in my right lower back. I noted that my right local multifidi had stopped working properly. I had a huge timing delay again. I worked on this for several days using the exercise I outlined in the local stabilizer section of my previous article.1 This was slow going, until my exercise coach suggested I first do a few brief squats to reset my lower back musculature.6 The timing delay was immediately almost gone, and I stopped having daily morning glitches. A brief global-stability exercise immediately improved my lumbar motor function. Another patient of mine with chronic low back pain when she gardened, had a similar response. This is not a miracle, just some good changes. I've shot a video for this article titled "Global Stability Tests and Exercises." Search YouTube for "MarcHellerDC" to see it.
Once again, I've attempted to distill and simplify someone else's comprehensive body of work. The goal is to introduce you to some newer concepts and some new ways of looking at rehab. You may already be teaching some of these exercises. Perhaps you will look at them differently, see where they fit and for whom they work. In the next two articles, we'll address both local stabilizer muscle function and higher-load training for the global stabilizers. This model has profoundly reframed how I look at rehab. I hope these ideas help you and your patients as well.
References
- Heller M. Core Stability Principles. Dynamic Chiropractic, www.dynamicchiropractic.com/mpacms/dc/article.php?id=53406.
- Bergmark A. Stability of the lumbar spine. A study in mechanical engineering. Acta Orthop Scand Suppl, 1989;230:1-54.
- Bradl I, Mörl F, Scholle HC, et al. Back muscle activation pattern and spectrum in defined load situations. Pathophysiology, 2005 Dec;12(4):275-80.
- Comerford MJ, Mottram SL, Gibbons SGT. Understanding Movement & Function. Concepts Course Notes. Kinetic Control, KC International U.K. www.kineticcontrol.com.
- Liebenson C. The Hip Hinge. www.lasportsandspine.com/pdfs/HipHinge-03.pdf.
- Spine Lengthening Squat. www.marchellerdc.com/pro_resources/Articles/spine_squat.pdf.
Dr. Heller's next two articles in this series are scheduled to appear in the Dec. 2, 2008 and Jan. 15, 2009 issues of DC, respectively.
Click here for more information about Marc Heller, DC.
Chad Brenzikofer, CSCS is owner and operator of Muscle Management Therapies, Inc., in Denver and an accredited tutor for Kinetic Control International and Performance Stability.