Achilles Tendinopathy in Runners: An Evidence-Based Guide

Achilles Tendinopathy: What Is the Pain at the Back of My Lower Leg?

You are likely to notice Achilles tendinopathy tfirst as a niggle or small ache at the back of your lower leg, above your heel. The pain is typically worse after periods of inactivity, e.g. when getting out of bed, or at the beginning of a workout and gets better as you warm up.

Other warning signs that you might be suffering from Achilles tendinopathy are poor ankle flexibility or a cracking sound when moving your ankle, which stems from scar tissue friction against the tendon.

What Is the Achilles Tendon and What Is Its Function?

Fun fact: The achilles tendon is the largest and thickest tendon in your body. You can easily touch and feel the Achilles tendon just above your heel, where it connects the calf muscle to your heel bone.

As you contract your calf muscles, the connected Achilles tendon transmits the power generated from your calf to lift your heel and to push your toes into the ground. Additionally the achilles tendon also absorbs shock as you land on your feet while running and helps to stabilize the body. When running the achilles tendon has to cope with forces corresponding to 12x your body weight. (1)

Achilles tendinitis typically begins as a mild ache in the back of the leg or above the heel after running or other sports activity. Insertional tendonitis typically causes pain where the achilles tendon is attached to the heel, mid-section tendonitis causes pain about 5 centimeters / 2 inches above that spot.

Why Is It Called the Achilles Tendon?

The Achilles tendon gets its name from Achilles, the “bravest, handsomest and greatest” Hero of the Trojan war from ancient Greek mythology. (2) When Achilles’ mother dipped him into the waters of the river Styx to make him invulnerable, there was a small spot where she was holding him and the water could not reach, leaving him vulnerable.

This is the spot where the Achilles tendon is located. This legend may feel very familiar to many (brave, handsome) runners who feel this spot is their personal weak spot where they get injured over and over again.

What is my Achilles Injury? Achilles Tendonitis vs. Achilles Tendinosis vs. Achilles Tendinopathy

Achilles tendonitis refers to inflammation of the Achilles tendon. Often, however, the Achilles tendon is not inflamed. Instead the collagen protein which makes up the tendon degenerates causing the pain, which is referred to as Achilles tendinosis.

Both conditions are often summed under the broader term Achilles tendinopathy (Achilles injury). Achilles tendinosis is likely the more common injury, but often diagnosed as Achilles tendonitis.

Tendonitis, the inflammation of the tendon, is thought to be the result of excessive too-sudden or too-forceful stretching of the tendon, which causes micro-tears. Tendinosis on the other hand is the result of overuse without sufficient recovery time.

While both describe pain in the Achilles treatment may differ, e.g. treatment of inflammation from Achilles tendonitis with anti inflammatories or corticosteroid injections can inhibit the healing of collagen necessary to heal Achilles tendinosis. (3,4)

Therefore many doctors now are less likely nowadays to prescribe these treatments. Luckily other treatment options work well for both Achilles tendonitis and tendinosis, which we will discuss further below.

As with most injuries, if your pain is sharp or does not go away after a few days make sure to see a medical professional. A good reason to do this is to avoid the risk of rupturing a tendon weakened by an untreated Achilles tendinopathy.

What Is the Recovery Time for Achilles Tendon Issues?

Achilles tendinitis can usually be treated within 10 weeks and often even within days, while treatment for tendinosis might take anywhere from 3 to 9 months.

Causes of Achilles Tendinopathy in Runners

Achilles tendinopathy is either caused by excessive force that stretches the tendon beyond its capacity to accept load or by continued overuse.

More specifically a Delphi study of world-class tendon experts provides further detail about risk factors for Achilles tendinopathy in runners: (6)

Risk factors for Achilles Tendinopathy that are intrinsic, i.e. specific to the runner include

Previous injury,
Advancing age,
Calf strength
Exposure to steroids (e.g. steroid injections for Rheumatoid Arthritis or other inflammatory conditions),
Reduced ankle dorsiflexion (ability to flex your foot toward your shin),
Higher weight,
Antibiotic treatment (e.g. fluoroquinolones prescribed for renal impairment),
Excessive foot pronation.

External risk factors for Achilles Tendinopathy include

Rapid changes in training load, which could be increases in distance, frequency, intensity, training modality (e.g. hills, speed work)
Footwear
Running surface

Treating Achilles Tendinopathy (Effective for Both Achilles Tendinitis and Achilles Tendinosis)

When treating achilles tendinopathy it is a priority to increase the range of motion and strength of the lower leg. The treatments below follow this logic.

Rest

The path to recovery begins with rest or reduction in the volume of your running, while still maintaining a basic level of activity to maintain strength. Depending on the severity of pain this could be a dramatic reduction in running volume, walking or cross training such as swimming, cycling or resistance training.

Do You Need to Rest or Can You Run With Achilles Tendinitis or Tendinosis?

Pain is a good guide – if an activity causes or worsens the pain reduce the volume further or change the activity. Also if the pain is severe enough to change the way you run it’s definitely time to rest to avoid further injury. Some experts suggest that a “three” on a ten point pain scale would be the maximum acceptable pain to continue (lower volume and lower intensity) running. (5, 6). Check further below for a full guide on how to return to running safely.

Use Ice

While the method of how icing helps with healing tendinopathy is unclear its effectiveness is proven for many tendon issues. Apply ice inside a bag and wrapped in a thin towel, or using a commercially available ice bag, for 15–20 minutes several times a day. Also use ice after running or other activities that stress the Achilles tendon.

Check Your Running Form’s Impact on Achilles Tendinopathy

Your running form could be a cause or contributing factor of Achilles tendinopathy. Checking your running form can help with healing and avoid a repeat injury.

Evidence on which running form characteristics contribute to Achilles issues is mixed, however expert practitioners are recommending these changes to running form to avoid achilles tendinopathy: (7,8)

Also minimalist shoes or barefoot running may contribute to achilles tendinopathy if the transition to minimalist running is too quick or performed with poor running form.

A running form analysis can identify strong deviations from known running form parameters, which allows to gauge the effect of modifying biomechanic elements on the runners’ Achilles tendinopathy.

An experienced coach, a physiotherapist specializing in running or Movaia’s online running form analysis are all good options to check your running form for these deviations.

Eccentric Strengthening Exercises for Achilles Tendinopathy

Eccentric strengthening refers to exercises that lengthen a muscle while under load and contracting. The efficacy of eccentric strengthening exercises as therapy for Achilles tendinopathy is well documented. They stimulate collagen production, alignment and linkage, making the tendon stronger. They may also simultaneously confer the benefits of stretches. (9,10,11,12, 13, 14, 15)

Eccentric strengthening exercises are best performed slowly and once or twice daily for three months.

In this video we demonstrate several effective exercises for eccentric strengthening of the Achilles tendon. In this video we demonstrate all these exercises:

If you prefer written instructions here are these eccentric strengthening exercises summarized in a few paragraphs:

Tip Toes Exercise on Both Legs

Stand with your legs straight.
Hold on to a wall, chair or handrail for stability.
Lift yourself up on your good leg
Lower yourself down on your bad leg, supporting your weight if necessary with your good leg
3 sets of 15 reps, twice a day

Modification: As above but with knees bent.

Progress to single leg tip toes once you no longer need support from your good leg when lowering yourself down.

Tip Toes on One Leg

Stand on your good leg only. Hold on to a wall or handrail for stability.
Lift yourself up on your good leg
Switch to your bad leg and lower yourself down
Aim for 3 sets of 15 repetitions, twice a day

Modifications:

As above but with knees bent.
As above but on a step, finishing with your heel below the level of the step.
Wear a weighted west, backpack etc to increase weight

Light Stretching

Light stretching has multiple benefits to support recovery from Achilles tendinopathy.

It prevents shortening and can elongate the muscle tendon unit. A longer muscle-tendon unit reduces the tension on the tendon during running.
Stretching can increase blood circulation which accelerates the healing process.

When performing stretches, move slowly and avoid sudden movements to avoid further aggravating the injury. Stop if you feel sharp pain.

Great stretches for the Achilles tendon are:

Soleus Stretch

Gastrocnemius stretch

Heel Drop

Hold onto a wall or handrail for stability
Put the ball of your “bad” foot on the edge of the step
Drop your heel, while letting your other leg hang loose
Hold for 45 seconds for 3 reps

Massage

Seeking a massage from a physiotherapist can equally accelerate the healing of Achilles tendinopathy. Deep-friction massage applied to the tendon encourages the generation of new collagen, reduced pain and increased strength and mobility.

Myofascial techniques can smoothen the fascia, relieve tendon tension and remove scar tissue, and trigger points in the muscle connected to the tendon, relieving tension on the tendon. (16,17)

Nutrition

Your diet can both hinder and help prevention or recovery from Achilles tendinopathy. Alcohol has been shown to be a likely risk factor for Achilles tendinopathy. On the other hand dietary supplements, especially collagen-derived peptides seem to lead to better clinical outcomes. These nutritional changes are best discussed with nutrition experts for a safe, individualized approach. (18)

Advanced Treatment Options for Achilles Tendinopathy

In most cases the treatments above will suffice and more aggressive treatment options are not necessary. For those that do require advanced treatments they will often choose one of these options after consulting with their medical provider.

Extracorporeal Shockwave Therapy (ESWT)

Extracorporeal shockwave therapy (ESWT) for achilles tendinopathy is a non-invasive treatment where a device sends shockwaves towards the tendon, to break up scar tissue and promote healing. There is good evidence of the efficacy of an ESWT Treatment plan for Achilles tendinopathy. (19)

Platelet Rich Plasma (PRP) Injections

Platelet Rich Plasma (PRP) injections are generated from your own blood. They contain growth factors that are postulated to accelerate healing of your Achilles tendon. Your doctor will inject PRP injections into or around the damaged tendon. Several studies point towards good effectiveness, however many have limitations, requiring further study. (20)

Dry Needling

During a dry needling treatment a thin needle is used to needle the injured tendon. The goal is to produce trauma to the tendon and thus promote an inflammatory response that causes a healing response. Typically this procedure is done with local anesthesia. (21)

High Volume Injections

High volume injections consist of saline, a local anesthetic and sometimes corticosteroids. The injection is typically guided by real-time ultrasonic imaging and intends to improve pain and function of the Achilles tendon. (21)

Glyceryl Trinitrate (GTN) Patches

GTN patches are used for heart disease patients where the patch is placed on the skin, the GTN absorbed through the skin layer and then opens blood vessels. The same effect is used when placing the patches on the skin over a painful tendon. While the exact mechanism is not yet fully understood the treatment has been shown to effectively reduce pain and patient satisfaction. (22)

In the rare cases where none of the basic and advanced treatments are bringing relief, achilles tendinopathy surgery is often considered as a last resort only, due to its invasive nature. DThe surgeon will remove damaged areas of the tendon and potentially use tissue from another part of the tendon, or another tendon for repairs. A 2016 studie found a success rate of 83.6% of surgeries for both open and minimally invasive surgeries. Minimally invasive surgeries however have a lower rate of complications. (23)

Return to Running After Achilles Tendinopathy

Tendinosis causes changes to the tendon which make re-injury more likely. It is therefore important to slowly and gradually return to running. A clinical commentary in the Journal of Orthopaedic & Sports Physical therapy recommends that running is acceptable when pain is minimal (1-2 on a 10 point scale) during daily activities. (24)

When returning to running it is important to continue the strengthening and stretching program.

The running program itself should develop progressively, i.e. start with slow speeds on forgiving surfaces. Now is also the time to slowly introduce changes to running form to alleviate achilles tendinopathy, such as moving from a pronounced forefoot towards a mid- or slight rearfoot strike.

A tool to help guide the training is the classification scheme shown in the table below. Depending on the type of activity performed a corresponding number of rest days is recommended. (The Achilles tendinopathy recovery exercises are performed both on rest days as well as active days).

As the runner’s pain reduces and fitness returns the activities considered “Light”, “Medium” and “High” will be updated in consultation with a medical professional.

Activity classification table
Pain level on scale from 0-10	Light	Medium	High
During Activity	1-2	2-3	4-5
Day after activity	1-2	3-4	5-6
Perceived exertion of Achilles (0-10)	0-1	2-4	5-10
Recovery days recommended	0	2	3
Example activity (reviewed every 3 weeks)	Walking for 70 min	Jogging on flat surface for 30 min	Running at 85% of pre-injury tempo speed for 20 min

Table adapted from Sibernagel et al. (24)

When can I consider myself “recovered” from Achilles Tendinopathy?

You can consider yourself “fully recovered” after running for a full running season without Achilles tendinopathy symptoms returning.

During that period it is crucial to follow a gradual, progressive training plan, preventive flexibility and strength exercises and supportive measures such as massages and nutritions. This gives you the best chances to avoid (re-)injury and keep running pain-free.

Finally Achilles tendinopathy can be a long lasting, frustrating injury, but take comfort from the fact that you are not alone. 10% of runners suffer from Achilles tendinopathy and about 80% of them recover within a year with an exercise protocol alone. (25, 26) With the knowledge in this article you are giving yourself the best chance to shorten recovery period and avoid re-injury!

Why not start with a Movaia running form analysis today?

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