Isometrics reduce tendon pain

Anyone with tendon pain will tell you, it’s a pain in the butt (hamstring tendon pain that is). If it’s your Achilles tendon, the mornings are a struggle and you may have stopped walking, running or playing with your kids. For the athlete, pain relating to the Achilles, Patellar, Hamstring or Adductor tendons can strip away power and spring needed for elite performance. The effects of tendon-related pain are not only profound but lasting – over 50% of people that stopped playing sport because of patellar tendon pain still had pain 15 years later going up and down stairs!!! (Kettunen, Kvist, Alanen, & Kujala, 2002). You can probably pick those with gluteus medius tendon pain – finding a painless sleeping position is a nightmare, so they are the ones ordering double shots lattes or sleeping standing up.

Eccentric exercises are most commonly used in treating tendons BUT are painful to complete (in fact the protocol is based on provoking pain) so adherence to prescribed eccentric exercises is understandably poor. Most of the research supporting the use of eccentric exercise is in older, non-athletic groups. When athletes are already training heavily, eccentric exercises have been shown to increase the risk of tendon pain rather than reduce it.  So what can we offer people with tendon pain when eccentric exercises are unlikely to be helpful?

Two trail blazers in the field, Jill Cook and Craig Purdam have been looking to improve our clinical management of tendon pain. These clever clogs used reverse engineering principles – knowing lower limb tendons find elastic loading (where they need to store and release energy quickly ie act like a spring) the most challenging and provocative, and that load is the fundamental stimulus to the tendon matrix, there must be some form of load parameters that positively affect the painful tendon…..  So what type of load??

We investigated heavy isometric quadriceps muscle contractions for their ability to induce immediate analgesia in 6 athletes with patellar tendon pain and used transcranial magnetic stimulation to look at the possible motor activation changes. First of all, we found that people with patellar tendon pain had HUGE amounts of cortical inhibition (as if their motor cortex was trying to limit the use of the quads). However, a single bout of heavy (70% MVC) isometrics reduced tendon pain pretty much instantly (and lasted at least 45 minutes), it also reduced the associated muscle inhibition, resulting in an increase in muscle strength. It wasn’t just about heavy load though as this cross over study also examined isotonic (concentric / eccentric) contractions and found no effect on inhibition, and that isometrics were superior for pain relief.

This is the first study to demonstrate analgesia from exercise in people with tendon pain and paves the way for more studies with greater numbers and longer term follow up. Clinically, we have been using isometric muscle contractions to immediately and temporarily reduce tendon pain (currently we get them to do it every few hours throughout the day). Importantly, this isn’t a painful exercise for people with tendon pain. People can do isometrics prior to sport as it doesn’t fatigue their muscles (in fact strength was improved in the study). Equally we have athletes that use isometrics after they play or train and they seem to pull up better the next day.  Clinically, we use it in many tendons but the only research so far is in the patellar tendon. An in-season RCT over 4-weeks has just been submitted so watch this space…

For anyone wanting to use this technique clinically here are a few key points. Tendons dislike compression so any isometric load should avoid compression, e.g. avoid compression of the Achilles insertion at the calcaneus in ankle dorsiflexion. Time under tension and load (i.e. weight) both seem to be important (based on pre-study pilot testing). Some people may need to start with below body weight loads (e.g. seated calf raise machine for an unloaded Achilles tendon) but the elite football player with Achilles pain will tolerate much greater load and will need greater than body weight. Time for the holds in the study was 45 seconds (five times) but may need some clinical tweaking if the muscle is shaking too much. Make sure the muscle is given complete recovery between holds when using isometrics for tendon analgesia – we used two minutes.

The most important thing from the research? Tendons seem to love heavy isometric load and it reduced tendon pain immediately.

What next for the future? Research this in other tendons. We also need to investigate what may be the best combination of load and time under tension. Lastly, we need to understand more about the corticospinal control of the muscle in tendinopathy and how we may need to address these changes in tendon rehabilitation to improve our outcomes for people with chronic tendon pain. If we can change inhibition immediately, can we modify our rehabilitation to restore motor control?

About Ebonie Kendra Rio

Ebonie Kendra RioEbonie is about to submit her phd in tendons and has completed her Masters in Sports Physiotherapy, Bachelor of Physiotherapy(hons) and Bachelor of Applied Science (Human movement). Her research has been awarded Best New Investigator 2004, 2013 and 2014 in Clinical Sports Medicine, best clinical science at Pain Adelaide 2013 and BJSM young investigator award 2014. Her clinical career has involved at stints at the Australian Institute of Sport, The Australian Ballet Company, The Australian Ballet School, Melbourne Heart football club, Alphington Sports Medicine Centre, Victorian Institute of Sport, Commonwealth Games 2006, 2010 Vancouver Winter Olympics, 2010 Singapore Youth Olympics, 2012 London Paralympics, 18 months travelling with Disney’s The Lion King stage show (Melbourne and Shanghai tour) and she was awarded the Post-Graduate Scholarship at the Australian Institute of Sport (2007).

References

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

Fredberg, U., Bolvig, L., & Andersen, N. T. (2008). Prophylactic training in asymptomatic soccer players with ultrasonographic abnormalities in Achilles and patellar tendons: the Danish Super League Study. The American journal of sports medicine, 36(3), 451-460. doi: 10.1177/0363546507310073

Kettunen, J. A., Kvist, M., Alanen, E., & Kujala, U. M. (2002). Long-term prognosis for jumper’s knee in male athletes. A prospective follow-up study. The American journal of sports medicine, 30(5), 689-692.

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. Br J Sports Med doi:10.1136/bjsports-2014-094386

Visnes, H., Hoksrud, A., Cook, J., & Bahr, R. (2005). No effect of eccentric training on jumper’s knee in volleyball players during the competitive season: a randomized clinical trial. Clinical journal of sport medicine : official journal of the Canadian Academy of Sport Medicine, 15(4), 227-234.

Woodley, B. L., Newsham-West, R. J., & Baxter, G. D. (2007). Chronic tendinopathy: effectiveness of eccentric exercise. British journal of sports medicine, 41(4), 188-198; discussion 199. doi: 10.1136/bjsm.2006.029769

Comments

  1. Good stuff, thanks.

    I hope we see measurements of cortical activity in more physio research. It would seem to be essential when attempting to identify the body’s effect on the mind and mind’s effect on the body.

    Makes me wonder what would happen if the subjects imagined strong contractions of the quads without doing the exercise. Presumably we’d get a decent increase in motor cortical activity, but would we also get pain relief?

    Ebonie Rio Reply:

    That is a brilliant question! There is great evidence for changing corticospinal responses with imagined contractions. We are looking to run a study that may provide some insight into this…watch this space!

  2. Makes sense. Use of isometrics to overcome inhibition of quadricep activation post knee surgery has been standard for quite some time. It would be great to see this being successfully used for chronic tendinopathies as well.

  3. Mikal Solstad says:

    EG,

    For what it’s worth, I have tried this with adductor-related groin pain with pretty much no clinical success.

    Ebonie Rio Reply:

    We do use it with adductor tendinopathy but general groin pain (from other locations) not sure of. It is similar in the knee – helps with patellar tendon but not vague non-specific pain

  4. Hey Mikal,

    Thanks for that. You tried the heavy isometric contraction or the imagined contraction?

    If the first one, did you get any short term pain relief like they’re describing here? Or you got some short term and no lasting effect?

    I notice it was single blinded, so operator beliefs and expectancies could have a massive effect here.

    It’s certainly an interesting study. Would like the full text if anyone has access. I’m assuming they jolted the contra-lateral motor cortex with TMS and attempted to find the threshold level of power to get the quads to twitch. More power required = more inhibited. Something like that. Ingenious.

    Ebonie Rio Reply:

    Agree re operator effects, however it was a randomised cross over study and we also tested isotonic contractions and didnt find the same result. If it was just exercise induced hyperalgesia or just the fact they were in a study, I will expect a similiar response regardless of mode of exercise, would you agree? We also had a baseline week to make sure that the TMS itself didnt chance outcome measures such as decline squat pain.

    EG Reply:

    “If it was just exercise induced hyperalgesia or just the fact they were in a study, I will expect a similiar response regardless of mode of exercise, would you agree?”

    Sure, I’d agree (I’m assuming you mean analgesia though). Something about load without movement seems to set it apart from other types of exercise. My guess is that pain and movement become strongly associated in the mind, so that movement triggers pain.

    I had a young bloke with a rotator cuff problem last night and about 1/2 ROM abduction with a lot of pain (not a wimp either). After all my usual EP stuff, I had only achieved another 20 degrees or so, which was pretty useless. So I decided to get him to do a very forceful contraction against resistance into abduction. After a few goes he got to end-of-range. In this instance it actually worked better than my usual rigmarole.

    If pain and movement are strongly associated, then that might explain the problem with movement-based strength exercises. A powerful isometric contraction avoids the triggering of movement-related anxiety and yet still tells the mind “if you can push hard like that you can’t have too much wrong with you!” > threat reduction -> analgesia.

    45 minutes of analgesia is a long time, and I don’t know of any other physical technique which would achieve that sort of duration of effect. I suspect it’s completely psychological in effect, which is great because it fits in with current themes about pain.

    EG

    Mikal Solstad Reply:

    Hi EG,

    Sorry for the vagueness, I’ve tried imagined contractions with groin-related tendon pain with no results.

    I have incorporated isometrics with suspected rotator cuff tendinopathy as well for the past 3-4 months, with great success.

    Interesting stuff.

  5. Jimmy Barker says:

    Would it be worthwhile in future studies blinding (literally) the subject to reduce visual feedback of say quads for patella tendinopathy or giving feedback via different means to see if this changes cortical inhibitory processes using trans cranial magnetic imaging?

    Jimmy