Yet another Tendinopathy update - managing pain by modulating the nervous system!
Tendinopathy is a topic that I seem to have returned to a number of times on this blog. But I do it for good reasons. First, Tendinopathy is a very common problem that brings people into clinic, and if there are so many with tendinopathy in the clinic, then I’m sure that there are a lot of people out there suffering with tendinopathy issues who never make it into any clinic, mine or otherwise. Second, our knowledge of tendinopathy and how to deal with it is evolving over time. Slowly but surely there is an increasing body of knowledge produced by researchers. And we can use this knowledge to improve our treatment approach.
What has already been discussed in this blog in the past is the value of heavy eccentric or isotonic loading. This means heavy strength training which is designed to induce remodelling in degraded tendon tissue. Remodelling means that the body lays down new, bigger and better organised collagen fibers to replace the damaged, weak and disorganised ones. There is good evidence to show that this type of strength training can improve tendon structure and resilience against injury in the medium term (3+ months). For more details see my previous blog post on heavy strength training for tendinopathy here:
One issue that is not adequately addressed in my previous writing on this topic that we will discuss here is that tendon pain is not always associated 1-1 with the state of tendon tissues. What I mean by this is that sometimes tissues can be degraded with no pain symptoms at all, and other times pain can be present even after the tendon tissue has remodelled to good condition. Furthermore the heavy strength training exercises that we know induce tendon remodelling can actually increase pain levels. This is why one of the original protocols for this type of exercise is called Alfreddson’s Painful Heel Drop Protocol! They knew what the gig was when they invented it!
Recent research has suggested that the pain of tendinopathy may actually be attributable to poor function of the motor neuron pathways that supply the muscles with signals. Each muscle has to be triggered by an electrical impulse delivered by a nerve. Nerves that supply muscles with these signals are known as motor neurons. “Motor”, as in, they get you “motoring”! get it? Research is showing that in cases of tendinopathy the signalling from your brain down these motor neuron pathways to the muscles and tendons is dysfunctional. The dysfunction can be varied, in that it can present as overly inhibited, or it can also be overexcited. One researcher describes the signalling as analogous to a teenager learning to drive a car with one foot on the gas and the other on the brake! The result is (as you might imagine) some humorously dysfunctional driving. In our tendons this dysfunctional drive may be a source of dysfunction and pain in the long term and may be part of the reason why tendinopathies can be frustratingly chronic injuries.
How does this knowledge change our approach to tendinopathy? Well, some of the most recent work on this problem is showing that we can normalise the motor pathway signalling by modifying the pacing of our strength training to follow an external cue like a metronome. Specifically, using the metronome, execute the concentric (lift) phase of the exercise in 3 seconds, and the eccentric (return) phase of the exercise in 4 seconds. 4 sets of 8 reps. Using the external cue -the metronome- is important as this is what the research is showing can have a positive impact on excitability levels in those neural pathways. Just to make it sound more science-y this protocol has been given the affectionate sounding nickname “Tendon Neuroplastic Training” (TNT).
Take a look at the video above, in it I describe how we can use a TNT approach with achilles tendinopathy. Of course the principles described can be applied to any type of tendinopathy elsewhere in the body but achilles is an easy to demonstrate model.
This technique does not provide immediate relief from tendinopathy pain. So if you are in the middle of a training season, you may choose to hold off on this exercise until you have a window where a competition is not right around the corner and in the meantime stick with the isometric exercises we discussed here which are great for quick relief of tendinopathy pain. However, if you are not training for any particular event or are in an off season go to town on the TNT method. This is great for remodelling the tendon like we want, and also helps to normalise motor pathway excitability which can help reduce dysfunction and chronic pain in the long run!
Further reading (if you really want to impress your friends)
Beyer, R., Kongsgaard, M., Kjær, B. H., Øhlenschlæger, T., Kjær, M., & Magnusson, S. P. (2015). Heavy Slow Resistance Versus Eccentric Training as Treatment for Achilles Tendinopathy A Randomized Controlled Trial. The American journal of sports medicine, 0363546515584760.
Habets, B., & Cingel, R. E. H. (2015). Eccentric exercise training in chronic mid‐portion Achilles tendinopathy: A systematic review on different protocols. Scandinavian journal of medicine & science in sports, 25(1), 3-15.
Rio, E., Kidgell, D., Moseley, G. L., Gaida, J., Docking, S., Purdam, C., & Cook, J. (2015). Tendon neuroplastic training: changing the way we think about tendon rehabilitation: a narrative review. Br J Sports Med, bjsports-2015.
Rio, E., Kidgell, D., Purdam, C., Gaida, J., Moseley, G. L., Pearce, A. J., & Cook, J. (2015). Isometric exercise induces analgesia and reduces inhibition in patellar tendinopathy. British journal of sports medicine, 49(19), 1277-1283.
Van der Plas, A., de Jonge, S., de Vos, R. J., van der Heide, H. J. L., Verhaar, J. A. N., Weir, A., & Tol, J. L. (2011). A 5-year follow-up study of Alfredson's heel-drop exercise programme in chronic midportion Achilles tendinopathy. British journal of sports medicine, bjsports-2011