by Dennis Zacharkow, PT
As evident from many television commercials, the auto industry continues to promote a passive, lounging driving posture with an excessive backrest recline.
An excessive backrest recline of 25° distorts the proper upright relationship of the head, neck, and upper back due to the visual requirements of driving. In order to achieve the proper visibility out the windshield, the driver pulls the head, neck, and upper back forward.1 The resulting distorted posture leads to neck pain, upper back pain, and headaches. In addition, the greater the backrest recline, the more the upper arms are lifted forward to reach the steering wheel, adding further stress to the neck, shoulders, and upper back.
Besides distorting the proper upright relationship of the head, neck, and upper back, an excessive backrest recline also distorts the proper upright relationship of the trunk and pelvis, by displacing the trunk behind the pelvis.1 Driving in such a lounging posture results in a relaxed core, with the driver having the same trunk muscle activity as an unconscious person!
An activated core through proper trunk stabilization is essential for providing an effective foundation for all limb movements.2 The end result is faster reaction times of the right lower extremity at the foot pedals and the upper extremities at the steering wheel. However, a lounging posture with a relaxed core results in delayed reaction times at the foot pedals and steering wheel.
An excessive backrest recline of 25° is also the basis for the flawed, forward headrest (head restraint) design of the last few years.3-5
As a result of the distorted forward posture of the head and neck with the recommended 25° trunk recline, the new headrests need to be designed a significant horizontal distance forward from the backrest, in order to be close to the back of the driver's head.
Unfortunately, for many drivers, these new forward headrest designs actually push the driver's head forward, resulting in neck/upper back pain, headaches, and distracted driving.
In general, the drivers most harmed by the new forward headrest designs are:
A slight side to side contouring of the backrest does improve comfort and helps keep the driver's posture as symmetrical as possible. This slight contouring is appreciated most by tall drivers.
However, a recent unfortunate trend in many car models is an excessive horizontal concavity to the backrest. This excessive side to side contouring distorts one's driving posture by rounding the back and shoulders, and restricting diaphragmatic breathing. The greater the horizontal concavity, the greater the risk for neck/upper back, mid-back, and lower back pain.
As Bennett explained back in 1928: "A deep, snug-fitting curve, however, is too confining for comfort. The line across one's back at the shoulders is practically straight, and a curvature in the support here tends to throw the shoulders forward and hinders expansion of the chest and related factors of erect posture." .6
Most health professionals agree with the auto industry and advocate the use of lumbar support. Among consumers, lumbar support is synonymous with the words "proper back support."
However, lumbar support does not deserve all this praise, because:
Lumbar support is located too high to prevent the rocking motion of the pelvis, and the resulting stress on the lower two lumbar discs.
Lower thoracic support elevates and stabilizes the rib cage, elongates the thoracic spine, and moves the upper trunk slightly forward. With the proper thickness of the lower thoracic support, the head and neck are positioned in a stress-free upright posture, with very slight clearance of the back of the head from the excessively forward headrest.
By elongating the thoracic spine and moving the upper trunk slightly forward, a lower thoracic support will also prevent the driver's thoracic spine and rib cage from sinking into the excessive horizontal concavity of the backrest. As a result, the typical round back, round shoulders posture will be corrected.
In addition, lower thoracic support provides counter-support for the pressure applied by the upper extremities when steering.
If the car backrest has an adjustable lumbar support, the lumbar support should be reduced to the lowest possible setting before adding sacral support.
Sacral support also provides counter-support for the pressure applied by the foot to the foot pedals. This additional stabilization is beneficial in preventing fatigue and pain from developing in the lower back/hip musculature.
The resulting "active-alert" driving posture with lower thoracic support, sacral support, and a slight trunk recline (5° to 10°) is called The YogaBack™ Posture.
The YogaBack Posture activates the elongation reflex of the trunk, resulting in optimal trunk stabilization through proper activation of the diaphragm, deep lower abdominals, pelvic floor muscles, and the lower thoracic erector spinae.7,11
Transforming one's driving posture to The YogaBack Posture is the key to relieving neck/upper back, mid-back, and low back pain -- and the key to faster reaction times at the foot pedals and steering wheel.
For more details on the science behind The YogaBack Posture, go to yogaback.com
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