The Debate Over Crunches and Spinal Injury | Prescription Fitness

There is a common misunderstanding that if you want to reduce abdominal fat and create a smooth stomach crunches are the answer.  As with anything the problem lies in many other facets of your fitness.  The featured research article in The Strength and Conditioning Journal vol. 33, no. 4 Aug. 2011 “To Crunch or Not to Crunch: An Evidence-based Examination of Spinal Flexion Exercises, Their Potential Risks, and Their Applicability to Program Design,” described studies related to spinal flexion exercises and spinal biomechanics.  Beyond the anatomical description of how vertebral discs help support the body’s structure, reduce impact, and allow for greater ranges in motion, the article pointed out different overuse diseases and injuries associated with repeated crunching motions.

Within the studies used in the article it stated that in skeletal structure there was a positive result of damage caused due to overuse of flexion of the spine.  It was noted by the author that this study did not take into account muscular and connective tissue.  This tissue is used to support proper skeletal system movements and support the discs as they move.  The article also gave suggested frequency, intensity, and repetition suggestions for crunches.

The benefits of spinal flexion were many.  Spinal flexion facilitates nutrient delivery to the intervertebral discs.  It causes a pumping action transporting molecules to and from the discs allowing them to balance pH levels, discard cellular waste products, and move larger molecules to and from the discs.

The article concluded that “there is a favorable risk to reward ratio provided that trainees have no existing spinal injuries or associated contraindications, such as disc herniation, disc prolapse, and/or flexion intolerance.”  They also theorized that mechanical loading facilitates healthy maintenance of spinal discs.  Basing their findings on current studies, they found that spinal flexion should not exceed 60 repetitions of lumbar flexion cycles per training session.  It is also important to have sufficient rest between dynamic spinal flexion to allow for muscle protein synthesis.  The standard for this is 48 hours.  Training on consecutive days should be limited to different body parts and specificity.  Ideally allowing this type of recovery will promote the most benefit in changing body composition.  Individualized training sessions specifically designed by a certified professional will allow for this periodization to be most effective.

With anything we do to enhance our fitness levels and performance needs there must be risk to reward analysis.  Crunches are designed to increase the rectus abdominous muscles, internal/external obliques, and transverse oblique.  When training clientele it is most effective to develop all aspects of the core. With core being a current buzz, work there needs to have ample time put on strengthening all of the above musculature, with consideration for the erector spinae, and low back musculature as well.  It is my opinion that equal time must be spent developing the core region equally.  There should be an exercise for each specific core muscle group.  Each training program developed at Prescription Fitness is specifically designed to target these areas.  Isometric and neutral spine core activities are the optimal starting points for structural strength.  A few select basic abdominal neutral strengthening exercises would be core bridge, side bridge, 45 degree isometric crunch, bench pillar, and physio ball plank.  In relation to youth trainingprograms, isometric core strengthening should be the first level when being introduced to core training.  It is with equal concern that starting at early ages (athlete’s edge) will increase the length of time that the spine will be subjected to higher levels of fitness.  Within this youth training, isometric core strengthening will be best utilized to reduce spinal flexion overuse injuries and develop core musculature.  With all things equal, core training is the best way to increase your athleticism, support your body, and enhance your productivity in reaching your fitness goals.  Core strength development is the key to a well rounded exercise program and proves to develop athletes of all ages