The Achilles tendon is the strongest tendon in the body, and for good reason! But it is often a sore spot. The Achilles tendon is a connective tissue structure that attaches the calf muscle complex to the calcaneous bone (the heel); it's responsible for lifting your heel off the ground. Achilles tendinopathy (which encompasses both Achilles tendinitis (inflammation) and tendinosis (degeneration)) occurs when the Achilles tendon is repeatedly strained and excessively overloaded. It is different from other injuries such as Achilles insertionitis (pain at the insertion point of the Achilles tendon on the heel bone rather than the midpoint of the tendon) and retrocalcaneal bursitis (inflammation of the bursa at the base of the Achilles).
So what exactly is going-on to cause tendinopathy?
Tendinpopathy can occur at any tendon in the body; when the load placed on the tendon is continuously too much and not enough time is given to recover from tissue breakdown. This causes the tendon structure to change (tiny microtears occur) and weaken, making the tendon even less tolerable at sustaining loads, and creating a vicious cycle.
Initially Achilles tendinopathy manifests itself as stiffness that resolves when warmed up and a gradual onset of pain during or after a run or activity - at this point preventative measures to increase ankle flexibility (dorsiflexion in particular) and rest, may prevent things from getting anymore serious.
Typically swelling or thickening of the tendon is present. Activities such as running (especially sprinting), stairs and walking on your toes that load the tendon usually increase pain. As the injury progresses the pain usually starts to become more frequent not just affecting active time but during daily life as well.
In chronic (longterm) cases the tendon structure changes, thickening and stiffeness of the tendon is a protective response of the body. Failure of an Achilles tendon results in an Achilles rupture or tear.
Potential Causes & Their Treatments
Initially aim to calm down and settle symptoms by managing the load placed on the Achilles tendon and through treatments such as calf stretching, taping, icing, anti-inflammatory medication (if physician approved), foam rolling and massage. Then identify and treat the potential cause(s)...
Training Load Error - too much, too soon - a rapid increase in mileage does not give the tendon enough time adapt to the load resulting in tendon breakdown. Speedwork and hill repeats which place greater demand on the Achilles also have an effect if not introduced at a manageable level. You must give your body time to adapt to new loads. The common rule of thumb is no more than 10% addition in training volume per week. Listen to your body and alter your training plan - that may mean full rest or cross training. Proceed with a graded return to running with rest days between each run to allow the tissue to recover.
Limited Calf Complex Flexibility - Ankle range of motion is important in not over stressing the Achilles tendon - the most important being dorsiflexion (bringing your toes towards your shin). You want to aim for 15-degrees (past vertical 90-degrees) of available dorsiflexion with a straight knee. The ankle is required to dorsiflex for ambulation - with limited ankle dorsiflexion altered movement patterns place more stress upon the Achilles tendon. With limited ankle dorsiflexion the heel is forced off the ground prematurely increasing the load on the Achilles tendon. By stretching your calf complex (soleus and gastrocnemius muscles) you can increase you calf flexibility. Tight hip flexors can also increase stress placed on the Achilles by promoting a premature heel raise due to lack of hip extension during gait putting undue stress on the Achilles.
Altered Biomechanics - excessive pronation (arch collapse), high arches and leg length differences can all play a role in developing Achilles pain. Orthotics are a proven treatment plan - altered biomechanics can cause the Achilles tendon to pull off-line contributing to Achilles tendinopathy. Orthotics can redistribute how the load and how much load is placed on the Achilles. A deep heel cup along with arch support often works well to improve the position of the heel bone, allowing the Achilles to pull in a straighter line serving to offload the tendon.
Improper/ Overworn Footwear - Achilles tendinopathy can also be caused by wearing old or inappropriate footwear. Replace footwear with a shoe appropriate for your biomechanics, foot type and sport. Sudden changes in heel height can change the load placed upon the Achilles tendon - moving from a shoe with a 10-mm drop from heel to toe to 4-mm will increase the load on the Achilles. A Pedorthist can recommend the correct shoe for you.
Running Form - Running form will affect the impact placed on your Achilles tendon. With ineffective running form greater stress is placed on certain structures. Change in running gait can alter the load placed on the Achilles. Some may find an increase in running cadence to be beneficial in offloading the Achilles tendon - by shortening your stride and landing closer to your centre of mass with your leg right underneath of you, as opposed to ahead of you and over striding, less load is placed on the Achilles tendon.
Calf Complex Strength / Endurance - Once symptoms are under control improve your tendon’s ability to handle load – this can be achieved through eccentric loading (heel dip exercises) and strength and conditioning work.
If you are suffering from Achilles tendinopathy make sure you give it the rest it deserves and treat it promptly.