Thought Bytes...
December 2004

Hands on the Wheel

When I learned to drive, back in the dark ages, my instructor taught me to place my hands at 10 and 2 on the steering wheel. The logic was that my reaction time would be less in this position because the weight of the arm would assist turning the wheel. The problem is that holding the wheel with the hands elevated requires the hands to continuously grip the wheel while simultaneously keeping the shoulders and arms elevated. This type of static contraction is known to result in a build up of lactic acid in the muscles. Inflammation, pain and muscle fatigue would actually decrease motor responses if the hands were held at 10 and 2 for long periods.

My friend's daughter recently took driving lessons. Her instructor taught her to place her hands at 9 and 3. The logic with this new position is that the hands and arms are less likely to be injured by the air bag in an accident. The hands are still held relatively high so that the weight of the arms can assist turning the wheel.

I have no problem with the 9 and 3 position for city driving, but I question it's validity for highway driving. With the hands at 9 and 3, the wheel can turn approximately 90o in either direction without needing to reposition the hands. But, when you are traveling 120 km / hour, turning the wheel 90o could have lethal consequences.

So, where is the best position? According to Bill Jewett at the Canadian Traffic Education Centre, we should actually place our hands at 8 and 4 for highway driving. From a muscular perspective, this makes far more sense because the muscles of the upper back, shoulders and arms can relax, so that they won't be as fatigued. Overall posture will improve because the weight of the arms is closer to the centre of the body.

From a safety perspective, Bill says that many severe accidents occur as a result of loss of control due to "over controlling". When the hands are held high and the car is traveling at a significant speed, abrupt movements of the steering wheel (more than a few degrees) are sufficient to elicit a skid. The drivers often over-compensate in an effort to recover, making the situation worse.

From a biomechanical and physiological perspective, holding the arms elevated requires static muscle contractions in the upper back, neck and shoulders as well as in the hands. Static contractions restrict blood flow to the muscles resulting in build up of lactic acid (a normal by-product of metabolism). This contributes to the burning feeling in muscles and can, over time, irritate the tissues. Additionally, the muscles are learning a shorter fibre length, making it harder to relax at the end of the day. Finally, in the raised position, the torso is encouraged to hunch and shift forward.

So, for safety as well as comfort, relax! Let your hands be lower when you are road. At highway speeds it may be safer and you will not be as stiff and sore when you get to your destination.

Feedback

Hi,

Just read your Dec 2004 article on "hand position". Those of us with trucking driving in our background have known about the "8 and 4" position for years, however it was because the steering wheel and our girth were both too big for us to get our hands to "2 and 10"!.

Merry Christmas
Steve, Fort McMurray

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