Core Stability: Is it all a Myth?

The Journal of Bodywork & Movement Therapies published an article by Eyal Lederman: The Myth of Core Stability. The following information is a summary of Lederman's conclusions.

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) does not seem to directly influence low back stability and/or pain.

Despite the exponential number 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 that demonstrates 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 (TrA), 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 preventative 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.

TAKE HOME POINTS

• Musculature 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

If accessible, I strongly encourage you to read the paper in full. While Lederman makes some valid points, it was quite interesting that of the 200+ references cited, only one was primarily authored by Stu McGill, a 2003 study at best. Further, much of the points Lederman alludes to have already been elaborated upon by McGill in his book, Ultimate Back Fitness and Performance (also available in my "Educational Resources" above). Again, the above information are merely a summary of Lederman's conclusions.


Make sure you leave a comment and let me know what you think!
Photo source