Note: This document is a “living” document. It is likely to grow and change in response to new research and personal experience.
Tendons are a fascinating structure in the human body. We think of them as boring rubber bands connecting muscle to bone, but in truth, they have some very unique structural properties. In addition, they have a capacity for adaptation, vital to their long-term and proper function. When this capacity is disturbed, tendons can become “sick.”
Tendinopathy is an umbrella term for diseases (pathologies) of the tendon. If you have pain localized to the tendon, you have “tendinopathy”. But tendinopathy is an umbrella term. It actually includes both tendinosis and tendinitis.
Tendinitis: Tendinitis is inflammation of the tendon. Most people know this. What most people don’t know is that the condition of tendonitis is actually quite rare in people presenting with tendon pain (tendinopathy). This is shown by looking at the blood, where inflammation “lives”. It’s simply not there in most people who present with tendon pain. This would explain why inflammation-oriented treatments are not effective for dealing with most cases of tendon-pain.
Tendinosis: Tendinosis is degeneration of the tendon, often taken to be caused by failed healing. It’s characterized by stiffness, a localized pain that seems to match the load placed on it, the warming up effect (pain is less when you’ve warmed up), and being sensitive to touch (8). Does this sound like you?
It is often taken for granted that tendinopathy arises from overuse. But simply high amounts of repetition is not enough to predict tendinopathy (3). The truth is, as of the writing of this document in 2014, there is a scientific consensus that the cause of tendinosis (and thus of most tendinopathy) is unknown. Load is an important factor, but definitely not the only one.
Though we don’t know what causes tendinosis, we DO know what tendinosis looks like, compared to healthy tendons, and that’s mainly an issue of tendon adaptation.
“These data clearly indicate that painful, overuse tendon injury is due to tendinosis” Khan and Cook (5).
Tendon Adaptations: the Good, the Bad, and the Ugly
Tendons normally adapt to load by stiffening, without changing thickness. In the case of the onset of tendinopathy, however, tendon adapts by thickening. “These initial changes…may occur because quick adaptation is necessary until longer-term change in either structure or mechanical properties (true adaptation) happens.“
These observations suggest that if you increase stress on the tendon beyond the primary (“good”) adaptive capacities of the system (such as increasing tendon stiffness), the system will engage in a secondary (“bad”) compromised form of adaptation (such as increasing cross-section area of the tendon).
These compensatory / pathological adaptations are less efficient than the primary adaptations. As a result, they are also likely to fail to keep up with load demands, and true tendon degeneration occurs: tendon cells begin dying (the “ugly”).
Something to keep in mind about these different kinds of adaptations: normal/good adaptations take 20 days to happen; compensatory/bad adaptations happen in days. (3)
When demand exceeds the capacity of normal (“good”) adaptive mechanisms, secondary (“bad”) compensatory mechanisms take up the slack. But these inefficient adaptations eventually result in (“ugly”) tendon degeneration .
Tending Your Tendons
The most highly supported modality for treating tendinopathy is eccentric loading (1). Eccentric loading involves resisting a muscle/tendon as it is lengthening. In addition to eccentrics, some studies have shown that basic prehab-type work reduced symptoms of tendinopathy (2). We describe some sample protocols below.
One major difference between studies showing success vs. no success with eccentric protocols is that success was associated with pushing through pain (6). Consider this along with a study demonstrating that concomitant rehab and continued training are as effective as rehab alone, when pain was not allowed to exceed 5 on a 1-10 scale. (8)
Although the research is still looking for an explanation from the perspective of cellular adaptations of the tendon, by looking at neuroscience of pain, we can come up with a concise explanation. By repeating the movement in a pain-free manner, we begin to dissociate the movement with notions of injury. In a sense, we re-define how we view the movement itself. Simultaneously, we provide the stimulus necessary for proper healing.
“Do I need to stop training while rehabilitating tendinopathy?”
No (8). Just make sure pain wouldn’t exceed 5 on a 1-10 scale.
“No negative effects could be demonstrated from continuing Achilles tendon-loading activity, such as running and jumping, with the use of a pain-monitoring model, during treatment. Our treatment protocol for patients with Achilles tendinopathy, which gradually increases the load on the Achilles tendon and calf muscle, demonstrated significant improvements.” Silbernagel et al. (8)
While we wait for the empirical research to validate the most effective protocols, we can begin to improve our functioning by experimenting with what works. Here are sample protocols based on research and experience, for dealing with various tendinopathies.
These protocols combine eccentric work (1-3 sets of 5-10 repetitions) with high volume prehab (3 sets of 20+ repetitions)
Eccentrics: Squats (consider elevating the heels to bias the quadriceps)
High volume prehab: Misalignment work, such as knee rotations
Eccentrics: Chin-ups (or barbell curls)
High volume prehab: forearm pronation/supination
Eccentrics: Calf-raises on a step, through a full range of motion
High volume prehab: Misalignment work, such as walking on inverted and everted feet.
NSAIDs? Stands for: No sir, altogether I dislike.
NSAIDs are not shown to improve long-term outcomes (1), and are associated with various side effects. In addition, they interfere with the healing process, and are known to increase incidence of injury/tendon rupture (4). The same can be said of corticosteroids (such as cortisone) (1).
1. Andres, B. M., & Murrell, G. A. C. (2008). Treatment of Tendinopathy: What Works, What Does Not, and What is on the Horizon. Clinical Orthopaedics and Related Research, 466(7), 1539–1554. doi:10.1007/s11999-008-0260-1
2. Bang MD, Deyle GD. Comparison of supervised exercise with and without manual physical therapy for patients with shoulder impingement syndrome. J Orthop Sports Phys Ther. 2000;30:126–137.
3. Cook, J. L., & Purdam, C. R. (2009). Is tendon pathology a continuum? A pathology model to explain the clinical presentation of load-induced tendinopathy. British Journal of Sports Medicine, 43(6), 409–416. doi:10.1136/bjsm.2008.051193
4. Ferry ST, Dahners LE, Afshari HM, et al. The effects of common anti-inflammatory drugs on the healing rat patellar tendon. Am J Sports Med 2007;35:1326–33.
5. Khan, K., & Cook, J. (2003). The painful nonruptured tendon: clinical aspects. Clinics in Sports Medicine, 22(4), 711–725. doi:10.1016/S0278-5919(03)00035-8
6. Maffulli, N., & Longo, U. G. (2008). How do eccentric exercises work in tendinopathy? Rheumatology, 47(10), 1444–1445. doi:10.1093/rheumatology/ken337
7. Rio, E., Moseley, L., Purdam, C., Samiric, T., Kidgell, D., Pearce, A. J., et al. (2014). The pain of tendinopathy: physiological or pathophysiological? Sports Medicine, 44(1), 9–23.
8. Silbernagel, K. G., Thomeé, R., Eriksson, B. I., & Karlsson, J. (2007). Continued sports activity, using a pain-monitoring model, during rehabilitation in patients with Achilles tendinopathy: a randomized controlled study. The American Journal of Sports Medicine, 35(6), 897–906. doi:10.1177/0363546506298279