motor control and low back pain
:rolleyes
I am aiming to better understand motor control and low back pain. I would love to hear comments on the follow topic.
Transversus Abdominis, Diaphragm, multifidus and pelvic floor muscle function may become dysfunctional during an incidence of low back pain.
Once pain has ceased and full functional control of neutral and direction is regained, will normal muscle function be restored or do we need to put emphasis on these in our rehab programs?
Motor control approach and lumbopelvic dysfunction
In the past many physical therapists have mistakenly believed that strength is the key to lumbar spine stability. We now know that motor control coordination is actually the key to stability. F. Kermode (who performs research on the deep stabilizing muscles using real-time ultrasound imaging at a physiotherapy clinic in Western Australia) reports that typical back exercise programs, like gym-based rehabilitation program, pool therapy, and Pilates are too advanced for low back pain patients prior to retaining the tonic holding capacity and isolated co-contraction of local muscles, including segmental lumbar multifidus and transversus abdominis.
Evidence (from peer-viewed medical journals, not the anecdotal kind that most PTs embrace here in the USA) suggests that TrA is dysfunctional in all back pain subjects independent of the type or nature of pathology, while subjects who have never had significant back pain do not have this dysfunction (Hodges and Richardson 1996). The dysfunction is related to motor control deficits not strength. Evidence has shown motor control dysfunction in TrA does not return to normal without specific exercise.
Motor control deficits of TrA may include: 1. Failure of a separate low load strategy for TrA control by CNS, 2. Increased recruitment threshold for TrA, 3. Recruitment of TrA becomes dependent upon direction of loading force (similar to global muscles), 4. Onset of TrA recruitment is delayed during limb or trunk movement (as seen during EMG testing studies) when compared to healthy individuals (TrA usually contracts prior to the prime mover of a limb), and 5. Phasic activation of TrA (just thickens the muscle) instead of a tonic TrA contraction that pulls laterally on the medial abdominal fascia to produce a corseting action.
Specific back exercises that focus on deep stabilizing muscles have proven to reverse motor control deficits that occur after back injury or degenerative change. The most significant finding thus far is that patients who receive physical therapy, but do not retrain their deep stabilizing muscles are 12.4 times more likely to have recurrence of back pain within 3 years.
In order to retrain transversus abdominis (TrA), patients are initially instructed to isolate and maintain a tonic contraction separate from the global muscles (e.g., abdominal obliques, rectus abdominis, and erector spinae). This is artificial since TrA contracts along with the global muscles during normal functional activities. But, it is necessary to train this isolated tonic contraction because the central nervous system controls TrA independently of the global muscles in individuals who have never experience back pain. But in dysfunction, this independent control is lost. Therefore, we must reprogram this separate motor control strategy for optimal lumbopelvic stabilization.
Abdominal ‘hollowing’ is a non-functional task that is used to isolate & retrain the mechanical action of TrA pulling on the fascial corset which produces stiffness between individual segments of lumbar spine and pelvis.
This protocol of isolation, training tonic holding ability, training co-contraction of the local muscles, and then integration with global muscles and into functional activities is an effective means of retraining the coordinated function of the local system (Hides et al 1996, 2001, O’Sulivan et al 1997, Richardson et al 1999).” (Diane Lee, The Pelvic Girdle, 2004)
Prognosis and Expected Treatment Times
Acute, first-episode low back pain. The prognosis is good for patients who receive training after first-episode lower back pain. In fact, people who receive no retraining of deep stabilizing muscles are 12.4 times more likely to have recurrence of back pain within 3 years. Those without previous history of lower back pain who present with acute lower back pain needed only 4 weeks of training for a 70% chance of no recurrence.
Chronic, recurrent low back pain. Another study was performed on people with chronic lower back pain (onset of LBP was at least 3 months prior to the study) with a radiologic diagnosis of
spondylolisthesis or spondylolysis. They received 10 weeks of training with statistically significant positive results. Specific back exercise training resulted in a decrease in pain intensity and disability. (The control group had no significant change.)
More info at: www.Back-Exercises.com
Re: Motor control approach and lumbopelvic dysfunction
The Motor Control Approach to lumbopelvic stabilization is not easy to grasp, even if you are a physical therapist. It takes quite a bit of extra study and clinical practice to understand.
Transversus abdominis (TrA) is part of the local system (part of the deep myofascial corset which is part of the deep myofascial cylinder) along with the following muscles that are generally accepted: respiratory diaphragm, transversus abdominis, segmental lumbar multifidus, posterior fasciculus of psoas major, and pelvic floor. More research has probably been performed on the transversus abdominis because it is easily imaged with ultrasound imaging and therefore is a clinically relevant muscle to target. Paul Hodges has done the majority of the important research on transversus abdominis. I would suggest that TrA is a window to local system dysfunction because of certain characteristics that are viewed with real-time ultrasound imaging.
Motor control theory can be simplified as follows:
Your brain may choose from two motor control strategies for stabilization, this is dependant on the amount of load that an activity places on the lumbopelvic region. Contraction of muscles for lumbopelvic stabilization is automatic and dependant on muscle-recruitment threshold: low or high. There is a “low load-bearing strategy” for “normal” (unloaded) functional tasks with low muscle-recruitment threshold and a “high load-bearing strategy” for “loaded” functional tasks with high muscle-recruitment threshold.
In individuals who have never experienced back pain, specific muscles are selected to contract at a low muscle-recruitment threshold for lumbopelvic stabilization during normal activities, whereas other muscles are not used for lumbopelvic stabilization until a higher threshold has been reached during loaded tasks. A low muscle-recruitment threshold means that a muscle is easily recruited during low effort, unloaded tasks. A muscle that has a high threshold will not be recruited for lumbopelvic stabilization until higher effort, loaded tasks.
Scientific studies on individuals who have experienced pain in the region show that the brain stops using a low load-bearing strategy to stabilize the spine and pelvis during normal tasks. Instead, the brain uses the high load strategy for normal tasks (the threshold is lower than normal). Therefore, the brain starts using a dysfunctional motor control strategy for lumbopelvic stabilization after pain is experienced in the lumbopelvic region.
Global muscle over-compensation (which results in co-contraction rigidity) may cause articular degenerative changes from axial compression on the joints of the lumbar spine and pelvis. Physical therapy must focus on down-training global muscle system through relaxation exercises and manual therapy techniques, initially. This is where all the techniques we learned during continuing ed courses will pay off (hopefully).
But, if you do not treat the local muscle dysfunction then your patient is almost guarenteed to experience recurrence of back pain. This should not be ignorantly denied. Physical therapists should embrace the motor control approach and will do well to learn more about these concepts. We really do not have anything else to treat low back pain that has shown efficacy as a treatment technique. Nothing else shows evidence of a decrease in recurrence.
If we do not learn these concepts, someone else will... Or, worse we will continue to do what has always been done because of tradition or because the authoritarian "guru" said that this or that technique will cure pain. Don't confuse the motor control approach with guru therapy. Gurus never have time to do any research (accept anecdotal) because they are so busy developing their concepts to match what they read in a physiology textbook. The development of Motor Control Approach has been through massive amounts of peer-review clinical research using internal EMG, real-time ultrasound imaging, and more.
More info at: www.Back-Exercises.com
Re: Motor control approach and lumbopelvic dysfunction
Quote "But, if you do not treat the local muscle dysfunction then your patient is almost guarenteed to experience recurrence of back pain. This should not be ignorantly denied"
SES WHO? All the research trying to relate the two is not the most compelling I have read. Just because motor control research has outweighed manual therapy research in the last 10 years doesnt mean we all have to jump on this bandwagon. Most of the research has been of a very poor standard compared to the much more powerful results that have shown general exercise to be the most beneficial route to a non-recurrence of LBP.
By the way...........in the clinical setting does a valid and reliable way of testing or treating local muscle function exist?
Re: Motor control approach and lumbopelvic dysfunction
Exactly, general exercise cannot be simplified to one specific technique that has inter and intratherapist validity. This is the point...neither can the human being. You have hit the nail on the head by the fact that something that occurs during exercise affects low back pain in a positive fashion. Trying to isolate that to one thing is proving very difficult and not particularly relevant. We should spend more time on what is the best form of exercise to combat LBP in the general population, of course with the assistance of all manual therapy techniques at our disposal.
:rolleyes
exercise , general or specific
Some sensible words from urigeller and superfiz, for all the weighty evidence in favour or specific "re-training" , one cannot deny that abdominal stregthening regimes done regularly are effective, be they specific with guidance , or just hacked away at by the untrained.
A fatigue resistant core group of muscles ready to accept load when inadvertant strain is felt , would obviously be better than to leave recovery to chance. The difficulty lies with patient compliance to routines requiring skill and sensitivity. The best exercise routine is the one that the patient will actually do, rather than a beautifully crafted regime with written material and an array of detail that is quickly put in the bin.
Re: exercise , general or specific
Quote:
Therefore, the brain starts using a dysfunctional motor control strategy for lumbopelvic stabilization after pain is experienced in the lumbopelvic region.
I agree and it's why you can help the brain/patient to restore a functional program. But what is a functional program? Certainly not a localized one!