I have previously written an article about Achilles tendonitis mentioning eccentric loading as the gold standard. However I thought that I would do a more in-depth article revising the exercise program, with the more recent research that has emerged including the long-term benefits of this treatment program.
What is eccentric loading?
Eccentric loading or heel drop exercises are the gold standard and first protocol for Achilles problems. This is when you place the ball of your foot a step and drop the rest of your foot and ankle of the back of the step. You should feel a stretch in the back of the calf as you do this. Eccentric loading is a dynamic stretch so it involves you to do a little work. Don’t worry its not difficult all you have to do it go from the position with your heel of the step to going on to your tip toes and then back down again. You can develop this exercise by doing it on one leg as well.
This type of exercise not only has the most evidence and has been deemed the most effective treatment for Achilles problems. It is also recommended by the UK government’s NICE guidelines. It is seen to have the best outcome in terms of conservative treatment especially for mid portion Achilles problems. (Magnussen et al (2009). It is well known to improve both the pain and the function of the calf and heel by between 60-90%. (Fahlstrom 2003) They have also found that 82% of patients were able to return to normal activities after 12 weeks after doing heel drop exercises. However this was not the case if patients did alternative exercises or stretches.
How does eccentric loading actually work?
It may not surprise you but like many things there are some controversy over the actual mechanism involved in the exercises especially to do with optimal load, frequency and duration that you need to do for the best results. The original guidelines for eccentric loading are the following:
The theory is that eccentric loading should increase remodeling and tissue repair in the tendons through improving the neuromuscular output or in posh words Therapeutic Mechano-transduction. (Khan & Scott 2009) In simple words the exercise works on reducing the load on the tendon and therefore the strain and force that the muscle will exert on the tendon and the amount the muscle will pull on the heel bone were it attaches. That means the exercises work to increase the length of the tendon, increase the efficiency when you tense your calf muscle as well as reversing the neovascularisation of the tendon.
There is evidence to show that the tendon cells will work together with the surrounding tissues in response to the loading from the exercise to induce the healing response needed to recover quicker and return the structure of the tendon back to normal. As there is a change in the vascular supply through the exercises this might explain why you feel less pain, as more blood and nutrients are able to get to the tendon to aid recovery and healing. Gardin et al (2009)
However there is contradiction in current studies on whether eccentric loading does change the actual structure of the tendon. However the research does show it will affect the way that the tendon itself works allowing you to resume normal physical activities pain free. Research generally points to eccentric loading aiming to make the tendon more flexible as well as increasing the strength of the calf by up to 18%. (Masood et al 2014)
A word of warning if you do have a partial rupture of the Achilles please check with your doctor first whether these exercises are appropriate as in some cases they can cause further damage to the tendon. (Alfredson 2015) While it is the gold standard there are some cases where the Achilles tendon does not respond to a heel drop program and this should also be considered. (Sayana & Maffulli et al 2007) Also there will be some patients that will not be able to start the heel drop program initially due to pain or calf weakness.
Variations of the exercises
The ‘classical’ program originally published by alfredson et al involved 12 weeks of 180 repetitions per day, which frankly is very time consuming for the average person. However there has been research to show a similar program where you only the exercises 3 times a week is just as effective and not surprisingly has a high patient satisfaction rating. There has also been research to show that the eccentric loading exercises are not enough to strengthen the calf muscles and that they should be partnered with specific functional exercises for the specific sports or movements. If your aim of your rehab or prevention of Achilles is primarily just to strengthen your calf then these exercises will not be enough. The practitioner should create a combined exercise rehab program that includes concentric stretch as well as specific movements you struggle with or are particularly important for you particular sport. Allison &Purdam 2009 while the eccentric exercises are the best for the rehabilitation of the Achilles tendon it is not the most effective at strengthening the muscle but can be seen as more of a passive stretch instead.
All the research seems to point to patients have a good long-term prognosis from Achilles tendonosis when following the heel drop exercises even if they have no treatment or stop doing the exercises completely after the initial rehab. Gardin et al 2009. This is especially significant considering that a large proportion of Achilles injuries are either degenerative or over use injuries. Therefore the chances of you have re-occurrences are particularly high.
In recent years there has been more research into the long-term benefits of eccentric loading program with research now available for 3-5 years after the original injury. The results from Van der plas et al 2012 show that after 5 years from completing alfredson et al study there was a significant improvement in terms of pain and physical activity that the patients were able to do 5 years on. Over 50% of the patients claimed they were satisfied to a good – excellent degree. It was also found that they had less tendon thickness and neovasculariasation in the Achilles tendon. Ohberg et al proved that many patients ended up having a normal tendon structure in their Achilles 2 years after the eccentric loading program. Van de plas study can be supported by research from Sibernagel et al would also found that 65% of patients were symptom free 5 years after completing their heel-drop program for between 12 weeks – 6 months.
To conclude not only does the research show that eccentric loading exercises are the most effective in the immediate rehab and enabling you to get back to your normal physical activity it is also extremely beneficial long term. Patients following a heel drop or eccentric loading program will continue to have reduced pain or be pain free and able to be more physically active up to 5 years after their original rehab. Therefore if you have now or in the past had Achilles injuries it would be a good idea to add this exercise to your normal routine when doing your warm up and warm down.