Imagine that 500 cars of the exact same make and model were assembled at the same factory by the same workers. If each of the cars was sold to a different person, would all of the cars break down at the same time? Of course not! How fast or how far a person drives is unique to that individual and to the specific day, so the wear and tear of the vehicle will be determined by how it is driven. Our bodies are our vehicles in life and how we move them will affect when the Service Light (or pain) will come on.
When humans are born, our bodies do not come with a User Manual. Fortunately, the field of biomechanics, which looks at the effects of movement and forces on the body, can help us understand how to use our physical bodies more efficiently.
I have been fortunate enough to work with and learn from a great number of injured people from various occupational backgrounds. After seeing how different people position themselves and move during home and work activities, I have gained a deep appreciation for the effect of postures and movements on pain. From these experiences, I have formulated a few principles of movement that will help you to perform more of your daily activities with less pain.
Principle #1 - Maximize your Base of Support
The structural frame of a human body, the skeleton, is simply a bag of bones. Without any muscles, this bag of bones would fall to the ground due to the force of gravity. People in pain often have weaker
muscles that cannot adequately support their mass against gravity (eg. when sitting, standing, walking, etc.), so the muscles go into spasm…resulting in more pain.
Your base of support refers to what is beneath you that connects you to the ground. Just as a house requires a broad and deep foundation to be steady, you need to have a stable base. The best way to do this is to lean against walls, countertops and furniture (Figure 1).
If there is nothing in the immediate space that you can lean on, then stagger your feet (Figure 2) or shift your weight onto the parts of your lower extremities that can tolerate more weight (Figure 3).
Principle #2 - Keep your arms as close to your body as possible
When you reach out with your hand, your arm creates a force (called a torque) on your body. The amount of torque depends on both the weight you are holding and the distance your arm is away from the body. According to the third law of Classical (Newtonian) Mechanics, every action has an opposite and equal reaction; therefore, to counterbalance the torque made by your arm, the muscles in the back of your body must tighten up in proportion to that torque (Figure 4).
In common English, this translates to: If you reach out with your arms, you will increase the tension (and pain) in the neck and back. You don’t have to be holding anything to generate a torque since your arm itself has a weight. This is why trying to grab a cup of coffee or reaching to use a keyboard can cause neck and back pain. So step close to an object instead of reaching for it and rest objects against your body or leg instead of holding it away from you when carrying an item (Figure 5).
Principle #3 - Anchor yourself
A common cause of injury and pain is unexpected forces on the body. A parent with chronic low back pain can attest to this every time they are interacting with their infant and the infant leans back all of a sudden. To avoid this, secure yourself and objects against something stable whenever possible so that unpredictable events do not cause excessive forces on your body (Figures 6 and 7).
Principle #4 - Rethink angles
How do you brush your teeth? Typically, people demonstrate what's shown in Figure 8.
This is not a good position since the elbow is away from the body and the arm is moving. Since every action has an equal reaction, the muscles in your neck, shoulder and back must all activate to counterbalance the forces produced by your arm. So the mundane task of brushing your teeth may actually be perpetuating your pain. By changing the way you hold the toothbrush (Figures 9 and 10), you can minimize the overall forces on your body.
How do you climb stairs? Commonly, people face the way they are walking. But in this situation, the forces on your knees can be quite high (Figure 11). Thus, this movement can be nearly impossible for people with degenerative changes in the knees.
If you change your angle toward the stairs and take one step at a time instead of alternating steps, you will not have to bend your knees as much, resulting in decreased forces and decreased pain (Video 1).
In general, if you feel increased pain during a task, try changing how you hold an object or angle your body differently.
Principle #5 - Use momentum instead of strength
According to the first law of Classical Mechanics, in order to change the movement of an object, you must give it a force. Consider the acts of vacuuming or ironing clothes in which you must constantly change the direction of movement of these objects. People tend to have their feet planted while moving these objects with their arms (Video 2). That's a lot of force that the arms have to generate over time! Additionally, the neck and back muscles will tighten in order to counterbalance all of those arm forces.
A strategy to minimize the muscular forces on the body is to create a momentum using the legs and letting the arms piggy back on that momentum to move the vacuum or iron (Video 3).
Now consider the act of getting up from a chair (Video 4).
The energy required for this movement can be reduced by using the head and upper body to create a momentum to allow the body to "fall upward" instead (Video 5).
Principle #6 - Always keep a neutral spine
Excessive bending (Figure 12) and twisting (Figure 13) of the body can cause tremendous stresses on the joints, discs and nerves in the spine resulting in debilitating pain. Therefore, it is important to avoid bending and twisting of the spine whenever possible.
In order to keep a straight spine when bending forward, use your hips instead of your spine (Figures 14 and 15).
In order to keep a straight spine when turning your body, pivot your feet instead of twisting your spine. (Figure 16).
It should be pointed out that "straight" does not necessarily mean "vertical." Many people believe that Figure 17 is the ideal posture for sitting.
However, the science shows that this vertical posture puts more loads onto the spine than standing (Figure 18)...and none of my patients have ever found this position to be comfortable.
Figures 19 and 20 demonstrate more relaxed sitting postures for people.
There are countless ways in which a person can position and move their bodies so I cannot possibly discuss all scenarios here. The purpose of this blog is simply to bring your attention to the connection between movement and pain and to give you some ideas about alternative ways of moving. You don't have to always adhere to these principles since sometimes it is not practical to follow a principle...but knowing about these principles will give you choices that you may not have had before...and these choices will give you more power over your pain.
Some of these strategies may not come naturally, so it will take some time to adjust. Be patient with yourself when trying to implement them.