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Time to Talk Tendons Part 1: What are Tendons?

Our last blog delved into all things load management. A common injury whose recovery is contingent upon load management is any tendon related injury.

You’ve likely heard of tendinitis, tendinosis, and tendinopathy. What is the difference between all of these terms? What category does my tendon injury fall under? How do I treat my tendon injury? Part 1 of this 2 part series will delve into what tendons are and the common diagnoses people receive in regards to their tendons. Part 2 will delve into the management of tendon injuries. Let’s jump in!

What are tendons?

Tendons are fibrous, cord-like structures that connect muscles to bones. Tendons are strong and stiff like ropes (the Achilles tendon can absorb up to 12.5 times body weight! (Maffuli et al. 2004) but tendons are also elastic like a rubber band. The job of tendons are two fold- they allow for the absorption of energy (think about pulling a rubber band back) and subsequently allow this stored energy to be transmitted (think about releasing the rubber band and watching it fly across the room).

Think about trying to tear the above rubber band with your fingers. This demonstrates the strength and stiffness of tendons. Yet, think about how far you can stretch and shoot the rubberband in the example above. This is similar to the elastic properties of the tendon.

Tendons are like bouncy (yet stiff) bridges. Think of the Ravenel Bridge like a tendon: with Mt. Pleasant being the muscle, the bridge itself being the tendon, and Downtown Charleston being the bone. The cement construction of the bridge (strong tendon) makes it stiff so as to absorb the weight of all the cars, while the white cables (elastic tendon) allow the bridge to disperse the forces of the high winds that come during hurricane season. The construction of the Ravenel Bridge is like the construction of tendons. Tendons absorb and transmit forces from our muscles in order to generate movement when we walk, jump, or throw. Any movement of the body is going to utilize tendons, even your eyeballs!

Where are tendons located?

There are tendons in the rotator cuff muscles of the shoulder that move when the shoulder muscles contract and relax, allowing the arm to move up and down and the shoulder blade to glide along with it. These tendons and muscles help to dynamically stabilize the shoulder but also allow baseball pitchers to throw the ball 90 mph.

The patellar tendon (right below the knee cap) and the quad tendon (right above the knee cap) allow runners and jumpers to sprint, jump, and hurdle at top speeds.

While tendons allow for highly athletic movements and power production, they also contribute to find dextrous tasks as well. Did you know there are actually no muscles in your fingers? Well there is 1 called the arrector pilli that allows the hairs on your fingers to stand up straight. But in terms of movement, it is actually the tendons in your fingers extending down from your forearm muscles that allow you to type, write, carry groceries, rock climb, and do all the fine motor tasks that your fingers do.

Categorizing Tendons: Is it an -itis, -osis, -opathy?

Most people come in to Made 2 Move wanting to know WHAT is going on with their tendons and causing them pain. Humans have a strong desire to categroze and attribute pain to a structural issue, but it is difficult and limiting to try and put ourselves into boxes based off an image or diagnosis.

You have likely heard of been to the doctor before and heard several different names used for your tendon pain. Maybe you were told that you have tendinitis in your elbow. Or maybe they said it was tendionosis of your rotator cuff. Or maybe you are a jumper and was told you have patellar tendionpathy. Which one is it? What’s the difference between the three?

  • Tendinitis refers to an inflammatory condition of the tendon typically characterized by an acute overuse of a tendon.

  • Tendinosis refers to degenerative changes in the tendon. “Osis” means degenerative, but as recent studies have demonstrated, degenerative changes can occur in healthy subjects (ie. after 1 football game), not cause any pain, and return to its normal state in just 4 days (Rosengarten et. al 2015).

Tendons are made up of primarily Type 1 collagen. Upon injury, studies have demonstrated more of the disorganized, Type 3 collagen present in the tendon than the organized Type 1 collagen. Yet, this disorganization of collagen happens in healthy athletes after just 4 games.

What we are referencing above is a recent study in which researchers gathered a group of 18 Australian football players, with 12 of these having no history of tendon pain or injury. After just one football game, there were structural changes seen in all 18 player’s tendons upon imaging, yet a majority of them reported no symptoms (Rosengarten et. al 2015). This emphasizes the issue with trying to attribute tendon pain solely to the changes that are happening on a cellular level.

  • Tendinopathy is an umbrella term and the most updated term we use to simply describe what is happening to the tendon. Tendinopathy refers to a change of the tendon. This could be a change structurally, functionally, or related to pain. After 20 years of studying tendons, Dr. Cook defines tendinopathy as “the clinical presentation of pain and dysfunction independent of structural pathology” (Cook et. al 2016). Regardless of the reason for your pain, it has been seen that through proper loading and rehab, tendinopathies can be reversible!

Why do tendons become painful?

Sometimes tendons are overused and can become painful. Sometimes tendons aren’t working the way they’re supposed to and become painful (ie. the rotator cuff tendons not moving in sync). And still, sometimes tendons are underused and can lead to pain. Tendons can also rupture or tear, and oftentimes this type of pain is sharp on the onset, then dissipates in the following days.

A 2019 research article notes, “The reduction in load capacity [of a tendon] may be due to the presence of pain or compromised tendon structure, or both” (Docking et. al 2019).

Regardless of the assumed reason for tendon pain, it is important to remember that correlation does not equal causation. Just because an image showed tendon degeneration doesn’t mean this is the root cause of your pain, as asymptomatic people may have the same findings on imaging without having any pain. This is why imaging can be misleading and, unless your therapist believes it will alter their treatment approach, is likely unwarranted with tendon related injuries.

Tendons are complex as noted in a 2016 article by Dr. Jill Cook, PT and researcher, as she revisited her tendon continuum research 7 years later: “The interplay between structure, pain and function is not yet fully understood, which has partly contributed to the complex clinical picture of tendinopathy“ (Cook et. al 2016).

The Tendon Takeaway:

The reality? Tendon pain and dysfunction lies somewhere on a continuum. What was once a tendinitis can progress to a tendinopathy and what was once a tendinopathy can regress back to a healthy tendon in which there is no pain or functional limitations.

The way in which you and your Made 2 Move therapist treat your tendon injury will depend upon the reports you give us and the movements we find provocative. Is it an overuse issue? You will likely need to briefly scale back the aggravating activity. Does this mean that you should simply rest, ice, and elevate your leg? No! Doing this will not build up the ability of your tendon to withstand the loads required for the activities you want to return to doing.

Dr. Cook notes in a recent podcast, “Clinically, we tend to worry about symptoms and dysfunction more than we worry about exactly what is happening in the tendon” (PhysioNetwork Episode 27). This is why what you tell us here at Made 2 Move is one of the most important parts of our exam.

Tendons can be tricky! Do I need to rest indefinitely? (likely not). Do I need to do more planks or squats? Run less? It can be tough to figure out what your tendon is trying to tell you. Working with a physical therapist at Made 2 Move can help you find the right balance between recovery and loading of the tendon to allow it to function in its most optimal manner. Reach out to today to set up an initial evaluation with one of our PTs!


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