Tensegrity

A few mornings ago I sat down to write a blog post about jaw pain and how it’s related to the alignment of our body. However, after writing about 3 paragraphs I realized that I’ve neglected to talk or write about the concept of tensegrity and how important this concept is to our health, specifically when it comes to pain.

To get to tensegrity though we first have to talk about biomechanics and to get to biomechanics we have to talk about physics. Luckily there are experts in physics and biomechanics we can rely on.

For instance Dr. Soutas-Little, Professor of Theoretical Mechanics and Director of both the Biomechanics Evaluation Laboratory and Biodynamics Laboratory at Michigan State University in East Lansing, Michigan.

He writes, “Classical, or Newtonian, mechanics is the oldest branch of physics devoted to the study of motion, the forces that cause that motion, and the internal forces that act within the body.” Essentially, “Biomechanics is the application of Newtonian mechanics to the study of the neuromuscular skeletal system.”

However, as amazing as newtonian physics sounds. There’s a problem with it when it comes to explaining how a living system actually works.

Let’s start with the basics.

When we think about movement of the body newtonian physics uses lever systems to describe how movement works in the body.

The head and the neck are seen as a class 1 lever system. Like a seesaw(image on the right).

The calf and the foot causing us to go up on our toes or help jump are seen as a class 2 lever system (image below). Like a wheel barrow.

The bicep and the arm are seen as a third class lever system. Like a fishing rod. A systems of pulleys and levers or cables and levers.

This all looks well and good and is easily explainable. Until you get into the math.

Let’s take a closer look at the biceps curl and how a lever system isn’t able to explain everything about how we work the way we do.

Take the picture on the right the forearm is the lever, the biceps “tension” (what the muscle and tendon are bearing) is the effort, the elbow joint is the fulcrum,  and the weight of the ball is the resistance. When the resistance is caused by the weight of an object it’s called the load.

In order for us to just hold up the ball based on newtonian mechanics the bicep muscle would be under tension stress of 433 pounds, math is below.

Load/Effort=Effort Arm/Load Arm

Effort Arm=1.5Load Arm=13

13.5/1.5=8.66667

Tension(T)= Weight of Ball x Load ArmT=433 Lbs

This would almost automatically rip the tendon from the bone. However, if you’ve been in a gym you’ve probably seen a fair share of people doing bicep curls with anything from 20 pounds to 60 pounds and you haven’t seen tons of people screaming as their bicep tendon rips from the bone.

Clearly, I’m missing something right?

Yes and also no.

Technically, yes the elbow is a first class lever system but that doesn’t paint the entire picture. If it did we’d have a lot less people in the gym doing bicep curls or even picking up coffee cups.

The reason for this is because the bicep isn’t the only muscle that is activated when you’re doing a curl and the tendon that is connecting the bicep to the bone isn’t the only part of this unit that is taking all 433 pounds.

The body isn’t just pulleys and levers. We’re a lot more complicated than that and if we were that simple the basic task of picking up a dumbbell or coffee cup would be catastrophic.

If newtonian physics doesn’t explain how we are able to move and function then what is the alternative that explains how we are able to move?

That answer lies in the phenomenon called tensegrity.

Tensegrity is defined as; the characteristic property of a stable three-dimensional structure consisting of members under tension that are contiguous and members under compression that are not.

So what does a tensegral structure look like? Pretty much the pictures on the right.

Let’s throw one more complicated definition in before trying to simplify it.

“Tensegrity is a lightweight space structure consisting of compression members (called struts) surrounded by a network of tension members (called cables). The rigidity of tensegrity is the result of a self-stressed equilibrium between cables and struts."

Tensegrity essentially is a system of wires and beams that hold themselves up and distribute compression to the other wires and beams which allows this structure to withstand more compared to a structure that isn’t able to disperse force or compression.

Let’s get back to the elbow and tie these concepts together. Remember when picking up a weight newtonian physics tells us there is a force down, a force up and a fulcrum in which the forces are translated on. In the terms of picking up a dumbbell the force, if newtonian physics was the only thing involved, would result in the failure of the bones, tendons, muscles, and ligaments.

Obviously that doesn’t happen. Here’s why. Due to tensegrity, instead of the bicep and the two bones taking all the stress of that movement the stress is distributed throughout the other muscles, ligaments, bones, and last and maybe most importantly the stress is transmitted through fascia (I’ll touch on the importance of fascia in another post).

If you look at the picture below you can see there is a lot more that is “holding together” and “dispersing force” than just the bicep muscle contracting and pulling the forearm up.

In fact many of the muscles that we thought worked a certain way are now understood to work differently and “coincidently” the way the other muscles work together matches how a tensegral structure works.

Let’s go back to the bicep. The bicep contracts and brings the lower arm the forearm closer to the body. The bicep is helped by the brachialis to bring the forearm to the body.

It used to be thought that the brachioradialis, the muscle at the top of the picture on the right, used to also help bring the forearm to the body. However, that’s no longer the case. It is now believed that when the brachioradialis contracts it pulls away the upper arm and the main bone of the forearm (the ulna).

The combination of the brachoradialis pulling away these two bones then allows for the dispersion of force throughout the surrounding tissues.

Voila, the elbow is a tensegral structure rather than just guide wires and a pulley system.

Now this concept of tensegrity is more complicated than the above writings and there are a lot more muscles and ligaments that are involved that make the arm a tensegral structure. However, I’m not going to bore you with what would be 2 more pages of words describing transmission of forces through ligaments and muscles.

I hope you enjoyed this little write up of tensegrity and continue to follow along. Next on the list of tensegrity topics in the body to talk about is fascia and the role it plays in tensegrity.

If you want to read a case of when tensegrity matters from a pain perspective a short blurb is below.

Why does tensegrity matter?

Imagine you’ve started to get pain in your shoulder. Right at the front of your shoulder and when you dig your thumb into the painful spot it really hurts. You also notice that when you pick something up you also feel a pull at the painful spot and it aggravates it.

You go to your doctor and tell them about your shoulder pain and how when you try and lift something you feel the pain in your shoulder. The doctor then like a magician goes right to the area where it’s painful, pushes on it and says, “Is that tender right there? If it is it’s probably just a little bicipital tendonitis from overuse. Take a week off any big movements, let it rest take an Advil to reduce the pain and inflammation and eventually it’ll go away.”

Tendonitis literally means your tendon is inflamed. Tendon=tendon. Itis=inflamed. Tedonitis= Inflamed Tendon.

It doesn’t tell you why the tendon is inflamed, how it has became inflamed and it doesn’t point you in a direction of actively improving the issue.

Most importantly of all it ignores all the other structures that could play a role in the increased stress on the tendon that has led to it becoming inflamed. It also ignores the fact that while it’s true the tendon is inflamed and painful it does nothing to address the why?



It assumes that the only way that the bicep tendon is inflamed is due to overuse of the biceps when it could be an issue with many of the other muscles in the arm that play a role in dispersing force throughout the body that led to the bicep taking the brunt of the load.

This often times leads to someone who has an area of pain, taking some time off the activity, the area involved starting to feel better, then months later another re-aggravation, more time off from activities and this cycle being repeated.



Or you see someone who understands tensegrity.