HOW TO LOAD THE ACHILLES AFTER TENDINOPATHY DIAGNOSIS

Lower Body

Feb 3

Knowing how much and how often to load a tendon can be challenging, especially following a diagnosis of tendinopathy when the most common cause of Achilles tendinopathy in athletes is excessive loading with insufficient recovery time. Intuitively, you’d think the solution to an overloaded tendon would be to eliminate the load. However, the clinical practice guidelines for Achilles tendinopathy do not recommend complete rest. Instead, patients should “continue with recreational activities within pain tolerance while participating in rehabilitation”. In fact the only Level A evidence for intervention found was exercise rehabilitation. So the question becomes, how do you properly load an overloaded tendon?

While this post won’t be focusing on how to diagnose Achilles tendinopathy in this article, it is important to discern whether you are dealing with insertional tendinopathy, mid-portion tendinopathy, or a proximal musculotendinous junction injury as treatment can vary with each. If you’re interested in discussing how to differentiate between these diagnoses, let us know in the comments and we’ll get to work on how to diagnose an Achilles tendinopathy. Once you have your diagnosis, rehabilitation can be divided into 4 phases: symptom management and load reduction, recovery phase, rebuilding phase, and return to sport phase.

phase 1: Symptom Management and Load Reduction

This phase is intended to stop the cycle of overloading the tendon. Again, completely eliminating activity can prolong recovery so it’s best to use symptom level as a way to guide this phase. One way to do this is to use the pain-monitoring model which breaks down NPRS values into zones and encourages the patient to remain within the safe and acceptable zones to manage load to the tendon. Current guidelines state that:

Pain is allowed to reach 5 on the NPRS during activity
Pain after completion of activity is allowed to reach 5 on the NPRS
Pain the morning after the activity should not exceed 5 on the NPRS
Pain and stiffness are not allowed to increase from week to week

In this phase it’s important to perform exercises that introduce minimal load on the tendon, in ways such as limiting load in dorsiflexion (especially with insertional tendinopathy) and completing low impact activities such as biking or swimming for cardiovascular fitness.

Relationship of the soleus and gastrocnemius at the Achilles tendon — The spiraling effect of the Achilles complex.

phase 2: Recovery

The goal of this phase is to re-introduce focused load to regain strength and improve tendon load tolerance. What’s interesting to note is that recent evidence seems to contradict well-established beliefs on how to load the tendon. Isometric exercises have been used as initial treatment for an irritable tendon, however studies have shown that isometric contraction is not superior to any other type of exercise. Similarly, eccentric muscle contractions have been utilized to improve tendon health but protocols involving isolated concentric or a combination of concentric and eccentric have all been used with positive results. At this stage of rehab it’s more important to find exercises that match the patient’s training preference to encourage adherence than focus on a particular contraction type.

Some modifications to consider in this phase are manipulating the position of the knee and ankle to alter loading mechanics. For example, if you want to target the soleus, consider flexing the knee. If the tendon is highly irritable, start in more relative plantar flexion and knee flexion and progress into dorsiflexion. The next phase of rehabilitation will focus on heavier loading and return to sport so it’s important to prepare the tendon for these activities with exercises such as heel raises in increasing ranges of dorsiflexion and heel raises with quick rebound to mimic plyometric activities.

phase 3: Rebuilding

Once the tendon is able to withstand consistent loading with no increase in symptoms, the rebuilding phase focuses on transitioning to heavier strength training and both running and jumping. The “Goldilocks” zone for positive anabolic response is 4.5-6.5% of tendon strain which, let’s be honest, means absolutely nothing to those of us in standard practicing clinics. As you can see in the image below, when the tendon is between 4.5 to 6.5% of strain, the tendon requires at least 50% of maximum volitional contraction (MVC). Most studies actually recommend closer to 70-90% of MVC, meaning you need to challenge the Achilles. The calf is a strong muscle; body weight single leg eccentric calf raises will not achieve 50% of MVC so this is the stage you need to load the Achilles, and load it well.

Relationship between strain and tendon force in healthy individuals

Chronic Achilles tendinopathy leads to a more compliant tissue, meaning the chronic strain on the tendon will actually result in the tendon becoming less stiff. Consider focusing interventions on gaining stiffness through the gastrocnemius, soleus, and Achilles tendon. The Achilles likes to be heavily loaded; the key is proper recovery. Current studies indicate that recovery time should be based on the intensity of training.

Light level activities can be performed daily
Medium level activities require 2 days of recovery
High level activities require 3 days of activity

While this may seem like a no-brainer, it’s important to note that the rebuilding phase overlaps greatly with the return to sport phase (meaning it should involve proper communication between physical therapists and S&C coaches). While the patient may only perform medium level activity with the therapist, that needs to be communicated to coaches to ensure proper recovery time is achieved between treatment and training sessions.

phase 4: Return to Sport

Because the patient may be pain-free at this phase of rehab, it is important to use RPE to determine the exercise intensity level and appropriate recovery times. Every 3-4 weeks exercises should be reclassified for their intensity and new high-level activities should be added to the program. These classifications should be determined by the clinician, patient, and coach.

Even once the patient has fully returned to sport it is important to continue monitoring symptoms, training load, and recovery time. Achilles tendinopathy is a slowly progressing injury that can be caught before it progresses but is often overlooked in early stages. If an athlete begins complaining of pain along the tendon that limits sport participation, it’s possible that changes to the Achilles tendon have been occurring for weeks or months. The first symptoms of tendinopathy are morning stiffness and minor pain through the Achilles that tend to be ignored as they do not limit participation in sport. Proper patient education on symptoms to be aware of can catch tendon changes early and minimize the negative loading cycle.

As we all know, treating tendinopathy is rarely a linear progression. Chances are you’ll have some setbacks but keep your focus on the overall goal. As always we’re a community focused on learning and making each other better practitioners. If you have any stories of success, recommendations, or even some “don’t do what I did” instances please share below!

If you’re looking for more information, make sure to read the full article on the Achilles architecture here and on loading parameters here.

About the Author: Erin Lynch

Erin is the Creative Director for Rehab Code and the person to ask if you want to know the answer to “how terrifying is it to switch to a non-clinical career with a degree designed to make you a clinician?” She’s the face behind the curtain of all Rehab Code content and tends to prefer to keep things that way. You won’t necessarily find much rehab related content on her instagram but if you want to see countless posts about her golden retriever Dave, she’s your girl.