The term "non-specific" low back pain (NS-LBP) arose from the realization that the exact source of pain can often not be identified. Many etiologies for NS-LBP have been proposed, and one theory, the focus of this review, is that NS-LBP can result secondary to malfunction of the muscular stabilizing system of the spine. Specifically, impairments in the function of deep stabilizing muscles such as transversus abdominus (TrA), multifidus, lumbar erectors and abdominal wall (comprised of internal/external obliques, rectus abdominus, quadratus lumborum) have been identified in previous research. The exact relation between muscle dysfunction and NS-LBP is still being elucidated however, as well as the best way to approach the clinical management of this problem.

Motor control exercise was developed based on the principle that many LBP patients have diminished control over their spinal stabilizing musculature. Normally, specific exercises are employed utilizing a motor-learning approach to retrain function, timing, and coordination of trunk and spinal stabilizing muscles (readers are likely familiar with these exercises, developed mainly by the Queensland physiotherapy group and McGill's spinal biomechanics lab at the University of Waterloo).

The purpose of this review was to evaluate the clinical effectiveness of motor control exercise in persistent NS-LBP by conducting a literature review. Three systematic reviews have been published on this topic (1,2,3), but newer trials have been published that were included in this review. Pertinent Results: Studies included in the review were grouped into four categories for analysis, each addressed separately below. 14 studies overall were deemed eligible for inclusion. A number of trials included in previous reviews (referenced below) were not included - these studies were excluded because they were performed on acute patients, included those with neck pain and headache only, or did not use a motor control intervention according to the review definition. No placebo-controlled studies were identified. Four new studies were included in this review - representing data on a total of 560 patients.

Motor Control Exercise vs. Minimal Intervention or as a Supplement (7 studies):

4 studies compared MCE to minimal intervention, while 3 used MCE as a supplement to another intervention
PEDro scores ranged from 4-8
pooled results favor MCE for pain, disability at each follow-up
these studies did not provide any evidence that MCE was effective for improving quality of life

Motor Control Exercise vs. Manual Therapy (4 studies):

PEDro scores ranges from 4-8
pooled results for pain and disability favored MCE - but the effects were small and only statistically significant in 2 of 6 estimates
pooled treatment effects on quality of life slightly favored MCE at short-term follow-up, but favored manual therapy at long-term follow-up

Motor Control Exercise vs. Other Forms of Exercise (5 studies):

PEDro scores ranged from 2-8 (the study with a score of 2 was assessed from a conference proceeding)
using a random effects model, the results indicate that MCE was better than other forms of exercise only for reducing disability in the short-term - these point estimates were small (5.1 out of 100) and suggest that MCE may be just as effective as general exercise, which would include less complex forms of exercise

Motor Control Exercise vs. Surgery (Lumbar Fusion)

the one study in this category has a PEDro score of 8
long-term follow-up on 61 patients revealed no significant difference in pain, disability, or quality of life between MCE or surgery

Clinical Application & Conclusions:

This review provides evidence that motor control exercise (MCE) can reduce pain and disability, forming an effective part of the clinical management of persistent non-specific LBP. It is more effective than minimal intervention and beneficial when added to other interventions. This review did not demonstrate that MCE is superior to other approaches such as manual therapy, other exercise interventions, or surgery.

Manual therapists should be aware of the evidence on this topic, as "core stability" exercises are commonly discussed in the popular media. The correct application of these exercises is paramount, and beyond the scope of this paper and Research Review. Contemporary clinicians should also maintain awareness that this review solidifies the recommendation that general exercise can be an appropriate treatment for chronic LBP as well, in addition to MCE, or in isolation - GET YOUR PATIENTS MOVING!.

This review does not cloud the picture for the management of back pain, but emphasizes the likelihood that there isn't one all encompassing answer for the management of chronic LBP. Interventions such as MCE are hard to study consistently among study groups, and factors such as patient group differences, intervention details and application, and so on, can influence individual trials. Unfortunately, the literature to date is too limited to tease out the effects of these factors.

Study Methods:

Trials included in this review had to involve patients with LBP that persisted beyond the acute phase - hence "persistent low back pain". This includes those with subacute, chronic, and recurrent LBP with or without leg pain lasting longer than 6 weeks. Studies had to be randomized or quasi-randomized trials comparing motor control exercise to placebo treatment, no treatment, another active treatment, or as an addition to another treatment (when included as an addition, motor control exercise had to comprise 40% of the treatment). Motor control exercise was defined as specific spinal stabilizing or core exercises targeting spinal musculature to improve coordination or the spine and pelvis (both Queensland and McGill approaches would apply here). Finally, one of the following outcomes had to be reported in each trial: pain, disability, quality of life, recurrence, or return to work.

Study quality was assessed using the PEDro scale (included studies received a mean score of 6 - range 2-8). Outcomes were extracted for short-term (less than 3 months), intermediate (3-12 months) and long-term (less than 12 month) follow-up. Scores for pain and disability were converted to a 0-100 scale.