Drivers Beware:
Lumbar Support Can Be Harmful To Your Health!

 

Wall Street Journal Posture Article Misinforms

by Dennis Zacharkow, PT
© 2014

According to a recent Wall Street Journal article "Slouch at Your Own Peril," by Jeanne Whalen1, "Seated posture, especially while using a computer, is critically important and deserves more attention, experts say, in part because it can affect a person's posture while standing and walking." A Mayo Clinic rehabilitation physician comments that due to the prolonged slumped posture in front of a computer, "Many deskbound office workers have started standing and walking in this position, too."

Are these so-called posture experts among the first to make this correlation - that poor sitting posture leads to poor standing and walking posture?

A little research reveals that decades before the advances in technology of our current information society, posture authorities from the 1920's and 1930's concluded that an individual's standing and walking posture is primarily the result of his/her sitting posture.

Here is what posture expert Dr. J.H. Kellogg said in 1927:

"The slumped posture is the natural result of the fact that our house chairs, the seats occupied by children in schools and by adults in churches, theaters, trains, street cars and other public places, are rarely constructed in such a way as to support the body in a normal posture when it is relaxed.

The universality of this condition among civilized people ... gives to this question of posture, and especially the sitting posture, great importance as a health factor. The standing posture is in general simply the natural result of the sitting posture".2

Posture authority G. Hawley (1937) also commented upon the effect of prolonged poor sitting postures on the individual's standing posture:

"...the relaxed sitting posture generally involves an abnormal degree of thoracic kyphosis with abducted scapulae and a forward position of the head.

Furthermore the increased kyphosis of the thoracic spine with depression of the ribs and a forward position of the head tend to become habitual, thereby increasing the difficulties of proper standing posture...

Thus the standing posture commonly seen in sedentary individuals shows a forward head, depressed thorax, round back, forward shoulders, and a prominent abdomen."3

The Wall Street Journal article then misinforms readers on the effectiveness of strengthening exercises to improve posture, and the effectiveness of a seat wedge for improving one's driving posture and relieving back pain.

To counteract the typical round shoulder/round back posture from prolonged computer sitting, a Mayo Clinic rehabilitation physician emphasizes strengthening the muscles in the upper back, "which hold the shoulder blades back."

Strengthening the muscles between the shoulder blades to correct a round shoulders posture is an example of a segmental approach to posture that is also a misconception. A physical therapy study in 1990 did not support the prescription of muscle strengthening exercises to correct a round shoulders posture.4 This study found no relationship between the force production of scapular muscles and the position of the scapulae in relaxed standing.

A holistic approach to posture considers round shoulders to be a general disturbance of the body’s balance.5 In the sitting position, lower thoracic spinal posture, pelvic posture, head posture, and arm posture are all interrelated to round shoulders.

Therefore, round shoulders result from flexion of the lower thoracic spine, excessive forward or backward tilting of the pelvis, a reaching forward of the head, and a raising forward of the upper arms from their balanced vertical position at the sides of the hips.6,7

Trying to correct a round shoulders posture with traditional strengthening exercises is simply a waste of the patient's time and money.

The article's potentially harmful advice on driving posture comes from a doctor of physical therapy at a New York City spine center. He advocates using a forward-sloping wedge cushion to correct a bucket car seat, so that "your behind is above your knees."

However, the postural alteration from driving with the hips several inches higher than the knees can result in additional risk factors when driving.

Oborne (1982) referred to the tendency of a forward-sloping seat to "destabilize the body and increase its tendency to slip forward. In addition the supporting advantages of the backrest will be less apparent." 8

These problems with a forward-sloping seat described by Oborne will be even greater when driving compared to sitting in an office chair, due to the movement of the vehicle: vibration, road shock, stops, accelerations. As a result, the forward-sloping seat will greatly increase pelvic instability when driving, as the pelvis slides forward on the seat, away from the backrest.

The resulting rocking motion of the unstable pelvis, intensified with the vibration and road shock of driving, increases the bending stresses to the lower lumbar spine. This is the major risk factor for developing a herniated lumbar disc from driving. 9,10

In their evaluation of office chairs, Bendix et al. (1985) found the pressure against the backrest to be twice as high with a slight backward slope to the seat of 5 degrees compared to a 10 degree forward-sloping seat. 11 When driving, a slight backward slope to the seat of approximately 5 degrees will help prevent the driver's pelvis from sliding forward on the seat.

In addition, a slight backward slope to the seat of 5 degrees will help retain the driver in the seat during a rapid deceleration or emergency stop. In contrast, a forward-sloping seat wedge, bringing the hips several inches higher than the knees, will actually increase the forward sliding force on the driver during a rapid deceleration, emergency stop, or rear-end collision.

(Please note: the actual degree of car seat slope is not determined with the car seat unoccupied, but when the seat is compressed by the weight of the driver.)

So, what is the most effective way to improve one's sitting, standing, and walking postures? The answer is not found in the Wall Street Journal article, but once again in the writings of the posture authorities from the early twentieth century.

Recall Dr. Kellogg's (1927) statement that, "The standing posture is in general simply the natural result of the sitting posture." In the sentence that follows, Dr. Kellogg concludes, "If the habitual sitting posture is such as to hold the body in proper form, the same poise will be maintained in the erect position." 2

As expressed by posture authority J.L. Rathbone (1934), proper chair design could improve standing and walking posture, because while the chair is holding the trunk in an elongated position, "the neuromuscular system is being patterned in a desirable posture which can carry over into standing and into movements." 12

From commuting to and from work, sitting at work, and sitting at home, spending 14-16 hours a day sitting is fairly typical. If this time sitting is done in an elongated posture, it is not only the most effective posture therapy for optimizing one's sitting posture, but also for optimizing one's standing and walking postures.

For sitting to pattern the neuromuscular system in an elongated trunk posture, one must stabilize the two key areas of instability: the rib cage and the pelvis.

  1. The Rib Cage
    In all slumped sitting postures (whether forward-leaning, upright, or reclining), the rib cage hinges forward and downward towards the pelvis in a position of postural depression. This is due to flexion of the lower thoracic spine, called the "hinge area" for spinal flexion. 13

    Adding a lower thoracic support to the car and chair backrest elevates and stabilizes the rib cage, while elongating the thoracic spine.13-15

  2. The Pelvis
    Compared to standing, where the hip joints are close to a fully extended position, the hip joints are in a mid-position when sitting. 9 This results in the freedom of the pelvis to "rock" or "oscillate" over the sitting bones (ischial tuberosities). The rocking motion of the pelvis over the sitting bones is a major cause of stress to the lower back.

    Adding a sacral support to the chair and car backrest firmly stabilizes the pelvis in its proper neutral position. 13-15 A firm sacral support prevents the intensified rocking of the unstable pelvis from the vibration and road shock of driving, thereby greatly reducing the bending motion and stress on the lower two lumbar discs. 10 Sacral support is the most important feature for preventing a herniated lumbar disc from driving.

The resulting "active-alert" sitting and driving posture with lower thoracic support and sacral support is called The YogaBack™ Posture. By activating the elongation reflex of the trunk, The YogaBack Posture is essential posture therapy for transforming one's sitting, standing, and walking postures, while saving the patient both time and money.

For more details on the science behind The YogaBack Posture, go to yogaback.com.

References

  1. Whalen, J.: Slouch at your own peril. The Wall Street Journal, June 24, 2014, pp. D1-D2.
  2. Kellogg, J.H.: Observations on the relations of posture to health and a new method of studying posture and development. The Bulletin of the Battle Creek Sanitarium and Hospital Clinic, 22:193-216, 1927.
  3. Hawley, G.: The Kinesiology of Corrective Exercise. Philadelphia, Lea and Febiger, 1937.
  4. DiVeta, J., Walker, M.L., and Skibinski, B.: Relationship between performance of selected scapular muscles and scapular abduction in standing subjects. Physical Therapy, 70:470-479,1990.
  5. Lovett, R.W.: Round shoulders and faulty attitude: a method of observation and record, with conclusions as to treatment. Boston Medical and Surgical Journal, 147:510-520, 1902.
  6. Fahrner: Das Kind und der Schultisch. Zurich, Schulthess, 1865. Translated in Cohn, H.: The Hygiene of the Eye in Schools. London, Simpkin, Marshall and Co., 1886, pp. 94-98.
  7. Sucher, B.M., and Heath, D.M.: Thoracic outlet syndrome -- a myofascial variant: part three. Structural and postural considerations. The Journal of the American Osteopathic Association, 93:334, 340-345, 1993.
  8. Oborne, D.J.: Ergonomics at Work. Chichester, Wiley, 1982.
  9. Branton, P.: Behaviour, body mechanics and discomfort. In Grandjean, E. (Ed.): Proceedings of the Symposium on Sitting Posture. London, Taylor and Francis, 1969, pp. 202-213.
  10. Sandover, J., and Dupuis H.: A reanalysis of spinal motion during vibration. Ergonomics, 30:975-985, 1987.
  11. Bendix, T., Winkel, J., and Jessen, F.: Comparison of office chairs with fixed forwards or backwards inclining, or tiltable seats. European Journal of Applied Physiology, 54:378-385, 1985.
  12. Rathbone, J.L.: Corrective Physical Education. Saunders, Philadelphia, 1934.
  13. Zacharkow, D.: ZACKBACK Sitting. Rochester, ZACKBACK International, 1998.
  14. Zacharkow, D.: Posture: Sitting, Standing, Chair Design, and Exercise. Springfield, Thomas, 1988.
  15. Zacharkow, D.: Women’s driving posture: an overlooked health issue. Worldwide Spine and Industrial Rehabilitation, 1(2): 5-10, Fall 2001. (Available online)

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