injury prevention

7 common causes of Achilles Tendon injury

From your feet to what you’re doing with them, take this advice to avoid a nasty injury.

Domhnaill Fox is an U21 All-Ireland winning hurler and a physiotherapist specialising in strength & conditioning and injury prevention.

IT WAS THE downfall of a Greek Hero and could also stop you from reaching your training goals.

The Achilles Tendon is the largest and strongest tendon in the human body but can also be quite troublesome in many athletes and sportspeople. You may have heard of an Achilles Tendinopathy or may have suffered it yourself at some stage.

Previously this condition was known as a Tendinitis, this is a common misconception. The suffix ‘–itis’ indicates presence of inflammation but laboratory imaging has shown that there is an absence of inflammatory chemicals. There is instead an increase in tiny blood vessels encroaching into the tendon itself. It presents as a niggling pain, sometimes with some general swelling in the area initially.


At a cellular level the collagen fibres become disarrayed and there is an increase in cellular fluid. At this point it is advisable to attend for physiotherapy to begin rehab and halt progression of the condition.

The Achilles Tendon is the shared tendon of the two calf muscles – the gastrocnemius and the soleus. The textbooks will tell you that the calf muscles plantarflex (point) the foot but during walking and running it serves a much more complex purpose. As your foot contacts the ground, the force must be absorbed by the body. The bones, tendons, muscles and ligaments of the foot, ankle, knee, hip, and pelvis all take their share of the load in a perfect individual.

However, in reality this is not the case for a number of reasons. Basically, if there is a weak link in the chain, some structures will suffer. These weak links may be due to stiffness, muscle weakness, poor motor control, or even just the way your bones and joints have developed.

Specifically in the Achilles Tendon, the tendon stores this force as elastic energy and uses it to aid the calf muscles when your foot is pushing off during walking or running. In certain cases, this load is increased due to failure of other structures to take its fair share. These failures are listed below:

1.  The foot

A stiff, high arch or stiff joints in the foot reduce their ability to absorb force when the foot strikes the floor. The full force is then transmitted to the Achilles Tendon and Tibia to be dissipated or absorbed. A foot that pronates (flattens) excessively also places additional load on the Achilles Tendon as the calf muscles need to produce a bigger effort to re raise the arch.

2. The ankle

Similar to the foot, if the joint lacks mobility then it increases the force through the Achilles Tendon when the ankle reaches its end of range.

3. The calf muscles

Weakness of these reduces their ability to absorb, transmit and dissipate the force from the ground. Also, if these muscles are tight then the muscle fibres and the Achilles Tendon are under increased tension as the ankle moves through range.

4. The hip

Weakness in the rotator muscles of the hip (e.g. gluteus maximus, gluteus medius) changes the alignment of the leg, with the knee collapses medially (knock knees).

This creates a mechanical disadvantage in terms of force dissipation as the muscles and bones are no longer arranged in a straight line up the leg. This leaves the burden up to the more distal structures, i.e. the Achilles Tendon.

These are all internal factors; there are also several factors which are external to the body:

5. Training load

A rapid increase in training mileage, intensity, frequency, or all of these may lead to the development of an Achilles Tendinopathy or any number of other overuse injuries. When this is increased carefully, with the body being given ample time to adapt to training changes, then these injuries can be avoided.

6 Footwear

A change in footwear may cause the same issues. If you are buying a new pair of shoes then you should break them in by initially alternating which shoes you wear on your runs.

7 Running surface

Changes in the surface you regularly run on is also a risk factor. Different surfaces can transmit increased loads and the structures of the feet and legs need time to adapt to these loads.

France's Ruben Indongo running in the Men's Marathon Morgan Treacy / INPHO Morgan Treacy / INPHO / INPHO

Therefore, in order to give yourself the best chance to avoid Achilles Tendinopathy, you must address these factors.

Regular strength training (when done properly) that addresses the aforementioned weaknesses is a proven method of avoiding injury in athletes. This training needs to be structured and planned correctly with regular and measured progression. Soft tissue mobility is also important and regular stretching and foam rolling of the calf, quad, IT band, and hips will increase the function of the tissue in terms of absorbing load during running.

You must also be careful about progressing or changing your training. Your body will not respond well to abrupt changes and any change must be done slowly and carefully.

Should you currently be suffering from the condition then your rehabilitation work will be a bit more specific to the Achilles Tendon, while ensuring improvement in the strength and load-bearing ability of the entire chain from top to toe.

One important facet of this rehabilitation will be the inclusion of isolated calf strengthening. This is due for the need of an injured tendon to be placed under high and progressive load in order to heal effectively. It is advisable to get your injury assessed by a chartered physiotherapist who will prescribe structured rehabilitation and advise you on your return to running.

Sports Med Ireland operate from a state of the art functional training and rehabilitation facility in a convenient, easily accessible city centre location in Dublin. We pride ourselves in our unique, co-ordinated approach to client care, training and injury rehabilitation.
Whether your goal is injury rehab, general fitness, weight loss, strength & conditioning or training for a specific sport or discipline we can help. We have experience and a proven track record in all these areas and will ensure at all times that our service to you is personalised to your goals, functional, progressive, challenging and motivating. Visit here.
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