Imagine you just purchased a new car and you’re getting ready to drive it off the lot. You get in, put on your seat-belt, adjust the seat and fix the mirrors. Now you are ready to roll. But wait; aren’t you going to adjust your headrest? You know the cushion that sits atop your seat. Are you telling me you’ve never set up a car’s headrest? Okay, most people haven’t and that’s a big problem.
Technically your head rest is a head restraint and has been federally mandated in front seats of cars since 1969. The primary purpose of the head restraint is to prevent serious injury to the neck and shoulders upon rear impacts. In 2008 the law was revised requiring all cars have adjustable head restraints so that they can be appropriately fitted to each occupant.
According to the National Highway Traffic Safety Administration (NHTSA) the head rest should be level with the top of the head or no lower than the top of the ear.
Additionally, the head restraint should be no more than 2 inches from the back of the head. If your car was manufactured prior to 2009 or you do not adjust accordingly the odds are that your headrest will provide little to no protection in the event of a collision.
Rear end collisions have a significant impact on US drivers. Over 1 million Americans a year are involved in rear end collisions which result in an estimated 2.7 Billion in medical costs. At minimum, symptoms can last a few weeks while in some cases can cause permanent changes to the spine leading to early degeneration and chronic conditions such as headaches.
The rationale for the Head Restraint is the trauma induced via the rear end collision commonly called Whiplash. When rear-ended our cars and bodies are subjected to rapid-fire acceleration and deceleration. Upon initial impact our body is lifted up causing a straightening of the entire spine. This phase known as Pre-load puts the spine in a position where all of its stability and ability to brace is lost. As force accelerates through the auto our body is forced into violent extension immediately followed by equally violent flexion as we decelerate. When positioned properly the head restraint absorbs much of the force subjected upon the head and neck in acceleration which in turn decreases the counter force of deceleration. Of note is that deceleration is aided by using the shoulder restraint and lap belt.
As if that isn’t enough reason to adjust your head rest, what if I told you that by properly adjusting your head rest and seat you could positively affect your posture? It’s estimated that Americans will sit the equivalent of 12 days over the course of a year just commuting to work. When you add in all the additional hours those same commuters will sit at work it becomes pretty evident that poor sitting posture can contribute to back and neck pain. By positioning the head rest at the required 2 inches from the head (or better yet touching the head) the seat back has to be in a relatively erect position. This re-positioning of the seat back pushes the auto’s lumbar support firmly into the small of the back inducing a normal lordosis and stabilizing the lower back. By inducing and supporting the lower back curvature, its normal and most stable position, we actually reduce the workload on the spinal muscles.
Those who feel pain and pressure at the tailbone area when sitting will also benefit from this positioning. As the lumbar curve is induced and supported the “slouching” position is negated and weight is positioned onto the sit bones (ischial tuberosity).
Lest we forget the neck and upper back, sitting erect helps keep the head centered over the torso which reduces neck and upper back strain. Shifting the weight of the head forward as little as 2 inches makes the head effectively 25% heavier creating muscular fatigue and pain.
Hopefully by reading this article the next time you are in your car you’ll pay more attention to how you are sitting and maybe even adjust that head rest/restraint.