Repetitive strain injury
‘Trucker’s shoulder’ is an injury that we see a lot with drivers who come into our office. It’s an injury that creeps up on a long distance truck driver over time. Pain is one of the last symptoms to show up. Pain may be felt in your upper arm, hand or fingers, as well as your shoulder, and can be quite distracting or even debilitating.
Because the symptoms may vary and many medical providers don’t understand the nature of an OTR driver’s work, this condition is often misdiagnosed, and the prescribed treatment does not address the cause.
So what causes ‘trucker’s shoulder’?
Long distance truck drivers know that U.S. highways have a built-in pitch to the right for water run-off. What very few people realize, is just how much effort it takes a driver to counteract this pitch to keep a vehicle on the road. Added to this is a tractor’s design to pull to the right as a safety factor in case the driver falls asleep at the wheel. A long distance driver has to constantly correct or pull the truck to the left to keep the rig in its lane.
Left shoulder repetitive motion
How much effort does it take?
Let’s say the average driver corrects for this road pitch once every second. And let’s say he exerts only 4 ounces of effort to make that correction. A driver will make that correction with “pull” effort, a lot more than with “push” effort. Here’s why – you have about 13 muscles to facilitate the “pull” versus 3 muscles to facilitate the “push”. So what happens is you’ll tend to pull the steering wheel with your left arm and shoulder, rather than push with your right arm, because it’s easier and takes less effort. And you drive for hours repeating this motion – hence developing repetitive motion or repetitive strain injury.
Let’s look at the cumulative effect of this repetitive strain over just one 70-hour work-week.
- 4 ounces of “pull”, times 60 seconds, equals 240 ounces or 15 lbs per minute
- An hour later you have pulled 900 lbs
- At the end of an 11 hour day of driving you have pulled 9,900 lbs
- At the end of a 70 hour work week you have pulled 63,000 lbs with your left shoulder
And you’ve been driving for how many weeks, months, years?
It’s just amazing that your body can take such a beating and keep on going. Until one day, your left shoulder says “Enough!” and the pain shows up. And you wonder why the darn thing hurts?
The repetitive strain on your left shoulder muscles and the muscle imbalance of working the left shoulder and not the right, causes your body to try to protect the stressed soft tissues in the region. For protection, it builds adhesive fibers between the muscle layers. The problem with this is these adhesions bind the muscles and other soft tissues, such as nerves, and prevent them from moving freely.
This is what you eventually experience as pain and restricted range of motion. It can also start to cause pain to radiate into your upper arm and may cause numbness in your hand, usually the thumb and first two fingers. If you don’t deal with this problem it will soon lead to a series of other dysfunctions in your back, neck, and arms.
What can you do to take care of this repetitive injury problem?
There are four things that set up ‘trucker’s shoulder’, but only one of them can be changed during your normal driving time.
The four things that cause repetitive strain injury are: 1) The frequency of the motion, how many times the same motion is repeated in a minute. 2) How much tension is created in the muscle groups during the action, muscle stress. 3) How much strength does it take to do the motion or action. 4) How often the working muscle group gets a rest from the given motion or action.
The one thing you can do to take preventative measures while driving is rest. But not what you normally think of as rest. In this case ‘rest’ means relax the working muscles. When one group of muscles are pushing or pulling the opposite group of muscles must relax to allow for the movement. So when you’re busy pulling on the steering wheel, one group is working and the others are not.
If you can remember to take your left hand off the steering wheel every fifteen to twenty minutes and do anything else with it, the working muscles think this is a rest period. Doc Kenn’s advice to drivers: “Left hand off the steering wheel, reach for the ceiling, reach for the floor, scratch you knees, your tummy and your nose”. A thirty second break from steering, with movement of any group of muscles other than the ones you steer with, is seen as a rest period for the steering muscles.
If you’ve been driving for months or years on end without taking preventative measures then a therapy session will go a long way to relieve pain, increase range of motion and improve muscle strength. Remember, pain only shows up when you already have a problem.
Doc Kenn uses a specialized soft tissue therapy called “active release technique” to release the muscles and nerves and allow them to move freely again. Addressing the soft tissue injury is just the first step. The next step is for you, the patient, to correct the muscle imbalance so the injury does not recur. Doc will recommend ways for you to improve your biomechanics to better support the problem area.
We see drivers in our office who’ve had this problem for a long time and it gets worse and worse. They’ve heard all sorts of diagnoses, from bursitis to arthritis to torn rotator cuff to old age, and yet no-one has addressed the cause.
It’s so nice to see a happy driver, who after just one session of active release technique, is amazed to see the difference - “I’ve got my arm back and my shoulder doesn’t hurt any more!” Once they understand about ‘driver’s shoulder’ they start talking with other drivers and find that many others are experiencing the same problem. Now they know “why the darn thing hurts” and what they can do about it.