Achilles tendon injuries are one of the most common and frustrating injuries for runners to develop. Pain is generally felt a few inches above where the tendon inserts onto the heel but can also be felt at the insertion point onto the heel bone (calcaneus). For the purposes of this article we will discuss exercise management strategies for mid tendon achilles injuries and focus on insertional achilles injuries in our next article.
For a long time, pain into the achilles tendon was referred to as ‘achilles tendinitis’, itis meaning inflammation. However, in recent years through the use of more sophisticated scanning and imaging techniques it is now known that inflammation is not a factor in a chronically injured tendon. The terms now used when describing this injury are achilles tendinopathy or achilles tendinosis. These terms recognise that injury occurs to the collagen fibres that make up the structure of the tendon. This is important to understand as it influences how these injuries should be managed.
When an achilles tendon becomes injured there is damage to the collagen fibres within the tendon. Initially, the damage is minor but because athletes are still able to continue training without significant discomfort, the damage to the fibres becomes greater and the body starts laying down fibrous tissue into the tendon to try and protect it from further damage. This fibrous tissue is less elastic than the previous healthy tissue and causes increased morning stiffness and pain at the commencement of runs. The appearance of the tendon may also change, causing it to look thickened (not inflamed).
Recognising the early warning signs and implementing appropriate management strategies is essential for recovery from this injury. At the earliest signs of pain stopping running and inserting a heel lift into your shoes for 2-3 days can help to prevent the injury from progressing. A heel lift helps to unload the tendon and prevent it from becoming overstretched. If you have access to a physiotherapist they can teach you taping techniques you can utilise to help unload the tendon further. In the acute stages of the injury anti-inflammatory medication may have some benefit in reducing symptoms but should only be used for 1 week or less as there is evidence to suggest anti-inflammatory medication interferes with the normal healing process of tendons.
If the injury has progressed into the chronic stage, commencement of an appropriate exercise routine is essential for the full recovery of tendon strength and structure. Complete rest is very rarely the answer, as it fails to assist in restoring the lost collagen fibre strength that has occurred as part of the injury process.
The most commonly used and effective strategy for management of chronic achilles tendon problems is eccentric heel drops. However, for these to be effective commitment to the program is essential. Complete recovery will not occur overnight and it can take several months to see significant changes in the function of the tendon. Too often, people give up on the program after several weeks when they fail to see any significant improvement. The heel drops with both a straight and bent knee need to be done twice a day, every day, completing 3 sets of 15 repetitions in both positions to be effective. Gradually over time these exercises have been shown to help restore the structure and function of the damaged collagen fibres within the tendon.
As you become more comfortable completing the exercises you can add weight in the form of a weighted backpack to increase the loading on the tendon. This increased loading will lead to greater strength adaptations in the tendon.
Success with achilles tendon injuries can also be achieved with heavy load resistance training. Similar to the eccentric heel drops it is believed heavy load resistance training assists in returning normal structure to the damaged collagen fibres. Generally, heavy load resistance programs start off with athletes completing 3 sets of a 12 rep max exercise of single leg heel raises, with both a straight and bent knee at week 1. Progression is made over a 7-10 week program so that by the end of the program athletes are completing 3 sets of 5 rep max of each exercise. Success of this program again comes down to consistency and also adhering to the correct loading of the tendon. 12 rep max means that a 13th repetition is impossible. This will take some trial and error initially to determine the correct load and will also mean athletes will need sufficient recovery time in between each set so they can still achieve the same repetition numbers on subsequent sets.
With both eccentric heel drops and heavy load resistance training it is normal to experience some discomfort into the tendon when completing these exercises. It is safe to continue completing the program as long as the pain and discomfort is gone or back to its normal resting level the following morning.
The most commonly asked question by athletes when dealing with achilles tendon issues is whether they are allowed to continue training or not. If the injury has progressed into the chronic stage I advise runners they can continue training as long as they fit the following criteria:
1) They have only minor to moderate discomfort into the achilles when they train and the discomfort improves or does not worsen as the run continues
2) When they wake up the following morning after completing a training session the pain and stiffness into the achilles is no worse than it was the previous morning. Increased morning stiffness and pain is an indication the condition is worsening and that training needs to be modified.