Achilles tendonitis is an inflammatory condition local to the Achilles tendon that can occur with repetitive use. This was once thought to be the main type of overuse Achilles injury, but we now realize inflammation plays less of a role in overuse injuries of the Achilles tendon, with other more specific non-inflammatory designations of injuries being identified.
These other overuse Achilles injuries include tendinosis, and the broader classification of tendinopathy. While there may be similarities in symptoms to different Achilles injuries, understanding the difference between the nature of these injuries can help optimize your treatment path and provide you with more confidence with self-management of this condition.
This article will discuss different types of Achilles injuries with a focus on overuse conditions, including Achilles tendonitis, tendinosis, and tendinopathy. While treatment will depend on extent of injury, other health issues that may be present, the individual’s task demands, and availability of clinics in your area, this article will provide a road map of what to expect with treatment and the general reasoning behind it.
Different Types of Achilles Injuries
In this section, we will discuss some of the differences and similarities between Achilles tendonitis, tendinosis, and tendinopathy, and how they all fit in together.
Achilles tendonitis refers to inflammation of the Achilles tendon itself. If you’re being investigated for this type of problem, the doctor or physiotherapist may also diagnose Achilles paratendonitis, which refers to inflammation of the sheath that covers the tendon and helps reduce friction with movement.
In either case, inflammation of Achilles tendon and paratenon can lead to a significant amount of pain that interferes with daily function. The pain and inflammation can be localized to the insertion of the tendon on the back of the calcaneus (formal name for the heel bone), in the mid-portion of the tendon itself, or the interface between the tendon and calf muscles, the latter of which is referred to as the musculotendinous junction.
Achilles tendinosis is an overuse condition of the Achilles tendon that does not involve inflammation, but rather, a degeneration of the tendon’s collagen fibers that results from repetitive strain. Sometimes prolonged tendonitis can lead to tendinosis, in which case tendinosis may occur in isolation or along with the inflammatory tendonitis.
Tendinosis can also occur at the insertion of the Achilles tendon on the back of the heel, in it’s mid-substance, or at the muscultendinous junction where the tendon and calf muscles meet. Tendons connect muscle to bone, and as such, they are often exposed to huge amounts of force, especially the Achilles tendon. If the tendon becomes damaged, even to a point that is considered physiologically normal, this damage can build up over time if there is not enough time between activity to recover.
While resting may help the tendon feel better in the short term, purely resting will not provide a long term solution, as the tendon now includes a disorganized matrix of collagen fibers, which can be thought of as the structural framework of the tendon. This is where activity-based treatment plays a big role in managing Achilles injuries, and we will explore this in detail in the sections below.
In the clinical world, Achilles tendinopathy is the term used for Achilles tendon pain resulting from repetitive strain. Recent research has indicated that inflammation is usually involved to a less degree than we once thought, which has helped identify more effective avenues for physiotherapy treatment (Kader et al, 2002).
Treatment for Achilles tendinopathy typically focuses on addressing the degeneration and subsequent disorganization of collagen fibers in the tendon as opposed to the inflammation itself, but with that said, Achilles tendonitis certainly can happen, and as such, should not be completely disregarded especially in the case of acute flare-ups.
Signs and Symptoms of Achilles Tendonitis
The main symptoms of Achilles tendonitis are pain and inflammation to the tendon, its attachment on the calcaneus, or its interface with the calf muscles. Achilles tendonitis pain may be increased with calf muscle contraction, such as a calf raise, the toe-off portion of walking, stretching the tendon, or direct contact.
If severe inflammation is present, there may even be Achilles tendonitis pain at rest, and the skin may look a little more red and more warm to the touch relative to the other side.
Physical Therapy for Achilles Tendonitis
When talking about pure inflammation of the Achilles tendon, physical therapy for Achilles tendonitis will focus on strategies to help provide a conducive environment for the healing process. While inflammation is a normal stage of tissue healing in the acute stage of an injury, Achilles tendonitis is not commonly associated with an acute injury, and the inflammatory process is considered dysfunctional at that point.
Applying ice or other forms of cryotherapy and taking anti-inflammatories represent the primary methods of managing Achilles tendonitis. Assuming no contraindications to cryotherapy are present for the patient, ice can be applied for 10-20 minutes at a time with a layer between the ice and the skin. This layer can be a dry or damp cloth, or even a sock.
Reasonably gentle range of motion exercises may be prescribed depending on the state of irritability. This will ensure the tendon and ankle can maintain or improve its range of motion, and therefore overall function, without further aggravating the inflammatory process.
Beyond that, general ankle strength and stability may be advised if the tendon is not too irritable. This will help build support around the ankle and take some of the load off the Achilles tendon during day-to-day activities, or even when it comes to return to sport. The calf muscles and Achilles tendon itself will eventually be strengthened as well, but there may be a hold time on this until these types of activities don’t significantly increase pain and inflammation.
When it comes to medications like anti-inflammatories, it is imperative to consult with a doctor or pharmacist prior to taking medications, especially if you are unfamiliar with the medications. Anti-inflammatories may be over-the-counter oral medications (e.g. Advil), topical anti-inflammatories (e.g. Voltaren), or more heavy duty anti-inflammatories that require a prescription.
Signs and Symptoms of Achilles Tendinopathy
*** Given that Achilles tendinopathy rarely includes a substantial inflammatory component, we feel that the word “tendinopathy” most accurately represents the majority of overuse Achilles injuries, and will use this word moving forwards for the remainder of the article. We did not forget about “tendinosis” – it is considered a major component of tendinopathy.
Achilles Tendon Pain
Symptoms may very between individuals, so we will focus on the most common presentations. The primary symptoms of Achilles tendinopathy, regardless of the proportion of tendonitis vs. tendinosis, is pain in the Achilles tendon or the back of the heel where the tendon inserts, the latter of which is often termed “insertional Achilles tendinopathy”.
This pain is aggravated with activity, especially repetitive activities that exert a right rate and/or amount of force on the tendon, such as long distance running, repetitive jumping (e.g. volleyball), or sports that involve repetitive loading in tight footwear (e.g. soccer). Pain may also be aggravated by direct contact such as tight or poor-fitting footwear.
Achilles Tendon and Calf Muscle Stiffness
Another symptom may be sensation of increased stiffness in the Achilles tendon or calf muscles. While some people may actually be quite stiff, not everyone will actually have shortened calf muscles or Achilles tendon when tendinopathy is present, which is a small part of the reason why stretching is now rarely recommended in physical therapy for Achilles tendonitis or tendinosis.
Thickened Achilles Tendon
A thickened Achilles tendon is a hallmark sign of Achilles tendinopathy. A thickened Achilles tendon may be visibly obvious, or it may more subtle and picked up on by palpating the tendon along its length. A thickened Achilles tendon suggests that tendinopathy has progressed to the point where it is now interfering with function, or at the very least, will be close to interfering with function sometime soon.
In addition to a thickened Achilles tendon, the tendon may also appear more red or flush, especially if there is any form of direct contact that is aggravating the tendon, such as a boot rubbing on the back of the heel or Achilles tendon.
Calcified Achilles Tendon
On x-ray or ultrasound imaging, the Achilles tendon may occasionally have some calcified portions, which is a somewhat common occurrence in more advanced tendinopathies. Many people are alarmed when they are told they have a calcified Achilles tendon, but this doesn’t mean the entire tendon is turning to a cement-like state. Rather, there are little bits of calcified pieces embedded within the tendon that can be causing pain, stiffness, and altered function.
Changes to Walking or Running Pattern
If the Achilles tendinopathy is causing enough pain or stiffness to interfere with function, this can often be identified when watching someone walk or run. Patients are often hesitant to bear their full weight in the toe-off portion of walking or running, whether or not they realize it.
This may translate to seeing the patient offload towards the other side during the toe-off phase of walking or running, which may also make it appear like an asymmetrical stride. If the pain is severe, accepting any weight at all may provoke symptoms, especially in the case of running or jumping where there is a higher rate of loading, and this may lead to a visible limp in all aspects of the stance phase of a walking or running cycle (stance phase = foot on ground, swing phase = foot in the air).
Physical Therapy for Achilles Tendinopathy
Physiotherapy for Achilles tendinopathy is counter-intuitive for most patients. Given the nature of tendinopathy symptoms, many patients think that resting the tendon and working on stretching are the way to go, and while this may provide temporary relief, an ample amount of research and clinical experience of clinicians suggests otherwise (Andres and Murrell, 2008).
We have come to understand that the best way of managing Achilles tendinopathy is to load the tendon, which can be achieved by performing specific strengthening exercises of the calf muscles. These strengthening exercises are often structured into a “heel drop program”, which is a progressive strengthening program to specifically address Achilles tendinopathy.
Heel Drop Programs for Achilles Tendinopathy
Many different heel drop protocols exist, and they may have subtle differences in their approach, but at the end of the day, it all involves strengthening the calf muscles as an avenue to load the tendon and build its resilience to repetitive strain. Eccentric exercise has been has been identified as an especially effective form of strengthening (Prudencio et al, 2023), which involves emphasizing the lowering portion of a calf raise.
It’s important to note that in-person care will help identify the best program for the patient, and ongoing follow-ups are highly recommended to ensure progression of the rehab program occurs at an appropriate time based on how the patient is doing.
Moreover, a certain amount of Achilles pain is acceptable when performing a heel drop program, so visiting a physiotherapist in person can help identify appropriate intensities of pain to work through.
With that caveat stated above, we will now outline a very general example of a basic heel drop program with hypothetical sets and reps below.
Phase 1 – Early Tendon Loading
– Ankle plantarflexion + dorsiflexion active range of motion (“ankle pumps”) throughout the day for circulation (Daily).
– Double leg calf raises on a flat surface progressing to single leg calf raises on a flat surface (3 sets x 15 reps, most days)
– Seated calf raises no resistance or very light resistance (3 sets x 15 reps, most days)
Phase 2 – Eccentric Loading and Increased Concentric Loading
– Double leg calf raises on the edge of a step progressing to single leg calf raises on the edge of a step adding resistance if able (3 sets x 15 reps with a focus on the slow lowering portion of the calf raise, most days)
– Seated calf raises with resistance or weights on top of the knees (3 sets x 15 reps, most days)
Phase 3 – Increased Rate of Tendon Loading
– Double leg calf raises off the edge of a step progressing to single leg calf raises off the edge of a step, with or without added resistance. In this case, the heels will drop to the height of the chair and will “catch” at that point, followed by a slow lowering (eccentric component) the rest of the way (3 sets x 15 reps, most days)
– Double leg hopping on toes (e.g. jump rope) progressing to single leg hopping on toes (3 sets x 15 reps, most days)
Considerations for Heel Drop Programs
The above example of a heel drop program is a good start, but it shouldn’t be a one-size-fits-all protocol. Some people will take longer to progress through the phases depending on the severity or duration of their tendinopathy, for example, chronic Achilles tendinopathy versus addressing it as soon as signs or symptoms arise. Comorbidities can also influence the recovery process, and these together are some of the reasons it’s highly recommended to consult with a physiotherapist about the suitability of a heel drop program.
Additionally, some people may respond slightly better to different types of loading. For example, some people will benefit from spending longer in Phase 2 and focusing on adding resistance, while others may respond better by moving on to increasing the rate of loading more quickly.
Given that cases vary, it’s difficult to say how long a person should stay in a particular phase. In general each phase usually lasts weeks, sometimes even months. This will seem like a long time, and while it’s not easy, it’s definitely worth it, and this type of activity-based rehab represent a more long-term solution to Achilles tendinopathy.
Other Treatments for Achilles Tendinopathy
Shockwave therapy for Achilles tendinopathy is commonly used in clinical settings and is an excellent adjunct to treatment for many tendon conditions. It works by stimulating the metabolism and circulation of tissue to assist in the healing process. It uses acoustic waves delivered in high energy bursts to initiate a cellular response in the tendon, which will assist in rehab (Paantjens et al, 2022).
Shockwave therapy is a pretty quick treatment. It can often be completed in the matter of minutes. Some people find they feel great for a few days after treatment, and this can also help buy a window to work in more comfortably. The downside is it’s not suitable for everyone (for example, those who are pregnant, those with blood clotting disorders, etc), and it can be quite painful in the moment.
Dry needling is a more indirect treatment to assist in Achilles tendinopathy rehab. We say indirect because the dry needling is more often performed in the calf muscles or other muscles that are consequently affected by general ankle dysfunction, although some practitioners are certified to apply the technique to tendons directly. This technique, when used in combination with exercise-based physiotherapy, has shown to be effective in the management of Achilles tendinopathy pain (Nuhmani et al, 2023).
Achilles tendon ultrasound is sometimes used in a clinical setting, especially if someone is looking for additional treatment but cannot tolerate shockwave therapy, or does not want to consent to it. However, evidence behind ultrasound for effective treatment of Achilles tendinopathy is weak, and as such, it should not be considered a high priority for treatment (Dedes et al, 2020).
People often interchange Achilles tendonitis with tendinosis and tendinopathy. Tendonitis means inflammation, whereas tendinosis means degeneration of the tendon. Tendinopathy is now a very common term used to describe the bulk of these injuries, as it refers to Achilles tendon pain from repetitive strain, which we have learned is usually not a purely inflammatory process.
Achilles tendonitis physical therapy will focus on reducing inflammation of the tendon, and after that is achieved, will likely transition to treatment that resembles Achilles tendinopathy treatment. The latter is heavily based in activity-based rehab, but may incorporate additional treatment methods such as shockwave therapy.
Andres, B. M., & Murrell, G. A. (2008). Treatment of tendinopathy: what works, what does not, and what is on the horizon. Clinical orthopaedics and related research, 466, 1539-1554.
Dedes, V., Mitseas, A., Polikandrioti, M., Dede, A. M., Perrea, A., Soldatos, T., & Panoutsopoulos, G. I. (2020). Achilles tendinopathy: Comparison between shockwave and ultrasound therapy. Int J Phys Educ Sport Heal.
Kader, D., Saxena, A., Movin, T., & Maffulli, N. (2002). Achilles tendinopathy: some aspects of basic science and clinical management. British journal of sports medicine, 36(4), 239-249.
Nuhmani, S., Khan, M. H., Ahsan, M., Abualait, T. S., & Muaidi, Q. (2023). Dry needling in the management of tendinopathy: A systematic review of randomized control trials. Journal of Bodywork and Movement Therapies, 33, 128-135.
Paantjens, M. A., Helmhout, P. H., Backx, F. J., van Etten-Jamaludin, F. S., & Bakker, E. W. (2022). Extracorporeal shockwave therapy for mid-portion and insertional Achilles tendinopathy: a systematic review of randomized controlled trials. Sports Medicine-Open, 8(1), 68.
Prudêncio, D. A., Maffulli, N., Migliorini, F., Serafim, T. T., Nunes, L. F., Sanada, L. S., & Okubo, R. (2023). Eccentric exercise is more effective than other exercises in the treatment of mid-portion Achilles tendinopathy: systematic review and meta-analysis. BMC Sports Science, Medicine and Rehabilitation, 15(1), 9.
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