By Dennis Zacharkow, PT.

From using cell phones to lacking sleep, the number of distracted and fatigued drivers on the road continues to increase. As a result, safe and defensive driving is more important than ever.

However, a major overlooked factor for enhancing safe driving is one's sitting posture behind the wheel.

Similar to executive office chairs, the backrest of the typical car seat has inadequate support for the rib cage and pelvis. As a result, leaning against the backrest results in a slumped driving posture that rounds the back and shoulders, displaces the head and neck forward, and restricts proper diaphragmatic breathing.

This common driving posture undermines safe driving by:

- Reducing Driver's Field of Vision
A slumped posture limits the ability to fully rotate the head from side to side. As a result, the driver's field of vision is reduced.

- Increasing Driver's Fatigue
Proper diaphragmatic breathing is critical for preventing fatigue and maintaining alertness when driving. With a slumped posture, diaphragmatic breathing is restricted and upper chest breathing increases. This leads to shallow inspiration and a chronic state of fatigue, a major factor in decreasing driver alertness.

- Increasing Pressure Discomfort
The backward tilting of the pelvis with a slumped driving posture results in the tail bone bearing excessive weight on the seat. Over time, the resulting discomfort and pain from this high pressure point can easily distract the driver. The distraction becomes very unsafe if the driver attempts to shift around on the seat for pressure relief while driving!

- Slowing Driver's Reaction Times
Activation of the trunk muscles is essential for stabilizing one's posture just prior to any rapid arm or leg movement. However, the trunk muscles are relaxed with a slumped driving posture. In a critical situation, this initial lack of postural stability slows one's reaction times at the foot pedals and steering wheel.

The most effective way to counteract a slumped driving posture is with YogaBack's Dual Back Support System to stabilize the pelvis, elevate and stabilize the rib cage, and elongate the spine.

References

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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.

Eklund, J., and Corlett, E.N.: Shrinkage as a measure of the effect of load on the spine. Spine, 9:189-194, 1984.

Evans, E.: Ergonomic aspects of the driving position - a postural analysis. In Ergonomics in the Tourist, Agricultural, and Mining Industries. Proceedings of the 22nd Annual Conference of the Ergonomics Society of Australia and New Zealand. Carlton
South, Victoria, Australia, ESANZ, 1985, pp. 250-255.

Hodges, P.W., et al.: Contraction of the human diaphragm during rapid postural adjustments. Journal of Physiology, 505:539-548, 1997.

Hodges, P.W., and Richardson, C.A.: Inefficient muscular stabilization of the lumbar spine associated with low back pain. Spine, 21:2640-2650, 1996.

Paris, S.V.: Cervical symptoms of forward head posture. Topics in Geriatric Rehabilitation, 5(4):11-19, 1990.

O'Sullivan, P.B., et al.: The effect of different standing and sitting postures on trunk muscle activity in a pain-free population. Spine, 27:1238-1244, 2002.

Richardson, C.A., et al.: The relation between the transversus abdominis muscles, sacroiliac joint mechanics, and low back pain. Spine, 27:399-405, 2002.

Zacharkow, D.: Posture: Sitting, Standing, Chair Design, and Exercise. Springfield, Thomas, 1988.

Zacharkow, D.: The problems with lumbar support. Physical Therapy Forum, 9(35):1,3-5, 1990.

Zacharkow, D.: Women's driving posture: An overlooked health issue. Worldwide Spine & Industrial Rehabilitation, 1(2):5-9, 2001.

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