Over this holiday season we are posting the most popular articles from the last five years. The fourth most read in our archive is on isometric tendon pain by Ebonie Rio.
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 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).
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