Research Review By Dr. Jeff Cubos©

Date Posted:

September 2010

Study Title:

The Myth of Core Stability

Authors:

Lederman E

Author's Affiliations:

Not reported

Publication Information:

Journal of Bodywork & Movement Therapies 2010; 14: 84-98

Background Information:

For more than a decade, core stability has played large role in the “prevention and rehabilitation” of many acute and chronic injuries, particularly of the lumbar spine. Thanks to research groups from all over the world, manual therapists have broadened their understanding of this topic and have employed various methods for enhancing patient care utilizing a number of approaches not limited to lumbar stabilization endurance testing protocols, exercise-induced abdominal muscle recruitment strategies, and motor control strategies for low back pain.

However, along with this plethora of evidence-based information have come generalized assumptions and beliefs pertaining to core stability training.

The purpose of this review by Eyal Lederman, an osteopath with a doctorate in physical therapy, was to utilize an evidence-informed approach to re-examine the various assumptions pertaining to core stability training in the management of patients suffering from low back pain.

Summary:

ASSUMPTIONS ABOUT STABILITY AND THE ROLE OF CORE MUSCULATURE

Despite the role of the core musculature in creating spinal stability...
  • Alterations and damage to the abdominal musculature (i.e. pregnancy, post-partum, post-surgery, etc) do not seem to directly influence low back stability and/or pain.
Despite the exponential number of research studies conducted in the last decade...
  • Low back pain has yet to be directly related to spinal instability.
TIMING

While the control of specific core musculature has been highly regarded in its "relationship" to low back pain...
  • Trunk muscles perform motor reorganization in the presence or expectation of spinal pain, yet this has not been shown to actually cause low back pain.
  • Traditionally prescribed core exercises do not effectively affect the timing of trunk muscle synergistic contraction nor do they reset onset timing in those suffering from chronic low back pain.
STRENGTH

While it is known that trunk muscle strength may decrease as a result of low back pain and injury...
  • No evidence exists to demonstrate that a lack of trunk muscle strength or endurance actually predisposes one to low back pain.
  • The findings pertaining to atrophy and a loss of trunk muscle strength resulting from chronic low back pain are still inconclusive.
  • Traditional core stability exercises do not provide enough of a stimulus to result in actual strength gains.
CORE MUSCLE ACTIVATION

There are still many practitioners that still follow the single core muscle activation concept (Transversus Abdominus), unfortunately...
  • Core musculature do not work independently from others within the trunk region during normal movements.
  • Evidence has yet to show that one can specifically activate a muscle group (within the trunk) in isolation.
THE RELATIONSHIP BETWEEN CORE STABILITY TRAINING AND MOTOR LEARNING

While training for an activity often leads to skill development in that activity (i.e. piano)...
  • Trunk control is activity specific (running vs. jumping vs. throwing), and thus, training to contract the abdominal musculature while on one's back is dissimilar to normal movement and therefore, conflicts with the basic principles of transfer and adaptation.
Although many novel core exercises are now performed in more "functional" positions (i.e. standing, moving)...
  • The internal-focus approach of having patients actively concentrate on contracting their abdominal musculature is counterintuitive to motor learning principles. Focusing on tasks external to the body is more conducive to performance improvement.
Furthermore, while individuals are constantly reminded to continuously tighten their core musculature...
  • The human body is designed to move efficiently and expend the least amount of energy possible, therefore, it is likely that energy will be wasted if co-contractions of the trunk musculature are continuously performed during normal daily activities.
CORE STABILITY FOR INJURY PREVENTION AND THERAPY

While an asymptomatic individual may present with weak abdominals…
  • Performing core stability exercises does not translate to prevention of injury.
While the research on core stability exercises for low back pain treatment seem promising...
  • Specific core exercises may be no different from general exercise or manual therapy.
CORE STABILITY AND ITS RELATIONSHIP TO THE CAUSE OF LOW BACK PAIN

While our understanding of the aetiology of back pain has increased tremendously over the last decade...
  • Chronic and recurrent back pain has been shown to be associated with psychological and psychosocial factors and its relationships to structural factors have been lessened.
  • Advising one to "brace" the core while seated is unlikely to offer additional protection against pathology and may in fact increase compressive forces sustained by the spine.
  • Core stability may have little preventive effect in those who suffer from acute back injuries (i.e. falls, sports) since these injuries often occur well before the nervous system is able to engage itself and offer protection.
POTENTIAL DAMAGING EFFECTS OF CORE STABILITY

Although compressive forces on the lumbar spine may contribute to low back pain...
  • These forces may actually come from core exercises themselves since abdominal co-contraction during movement may provide further increases in spinal compression.
  • "Natural" strategies of trunk control have been shown to be more superior to abdominal "hollowing" and "bracing" without the unwanted and excessive spinal compression.
While core training may be aimed at biomechanical dysfunction...
  • Continual focus on these methods may shift the focus away from potentially more therapeutic interventions, such as in those suffering from pain associated with biopsychosocial factors.
  • Core stability training may actually promote chronicity.

Clinical Application & Conclusions:

Based on Lederman’s investigations, the following conclusions and take home points were provided:
  • Muscle weakness and imbalances may actually be a normal variation rather than a pathology
  • Isolating the trunk musculature from the entire body may simply act as a means to promoting the "core" industry
  • Abdominal weakness/dysfunction may never lead to back pain
  • Trunk contraction may provide very little to back injury prevention
  • Core stability may not be any more effective than general exercise or manual therapy
  • The therapeutic influence may actually be a reflection of general exercise effects rather than stabilization
  • Continuous trunk contraction may actually lead to unwanted spinal loads
  • Traditional "hollowing" and "bracing" techniques may actually be unnecessary
Note, please remember that the above are the opinions of the original author and not necessarily those of Research Review Service or its contributors.

From these conclusions, it seems as though we as manual therapists and rehabilitation specialists may need to revisit the approach taken in core stability training. In particular, if an internal-focus approach to stabilization is indeed counterintuitive, perhaps reactive neuromuscular training may be a prudent alternative (1,2).

Additionally, should specific core exercises indeed be no different than general exercise for injury prevention and therapy, then a periodized exercise program, as suggested by Kell (3), may be sufficient in the rehabilitation of non-specific low back pain.

Study Methods:

This study was a “critical” review of the literature. No search strategy, inclusion/exclusion criteria, or quality appraisal of included studies or search results were presented.

Study Strengths / Weaknesses:

As neither a systematic review nor meta-analysis was performed, standardization in the critical appraisal of the literature was most certainly lacking. This was evident in the omission of a large number of studies performed by prominent researchers in low back pain and rehabilitation. In particular, of the 200+ studies cited, this paper included only one study primarily authored by the well-respected Stuart McGill (from the University of Waterloo in Canada).

Additionally, while Lederman attempted to dispel the “myths” surrounding core stability, he failed to provide a working definition at the outset. The notion of “core stability” is vague in its most literal sense, and delineating between such concepts as intersegmental stability, lumbar endurance, and strength may have enabled him to conduct a more focused literature review and subsequently, more accurate conclusions.

Finally, while he presents a conclusion that may be perceived as the need to ignore a specific approach to low back pain rehabilitation, he also fails to provide his readers with a succinct solution to this seemingly nebulous hypothesis.

Additional References:

  1. Cook G, Burton L & Fields K. Reactive neuromusculature training for the anterior cruciate ligament-deficient knee: A case report. Journal of Athletic Training. 1999: 34(2); 194-201.
  2. Voight ML, Hoogenbook BJ & Cook G. The chop and lift reconsidered: Integrating neuromuscular principles into orthopaedic and sports rehabilitation. North American Journal of Sports Physical Therapy. 2008: 3(3); 151-159.
  3. Kell RT & Asmundson GJG. A comparison of two forms of periodized exercise rehabilitation programs in the management of chronic non-specific low back pain. Journal of Strength & Conditioning Research. 2009: 23(2); 513-523.