BRINGING SCIENCE TO TREATMENT

Midsubstance Achilles tendinopathy: what’s the endgame?

Lachlan Wilmot explains the importance of end-stage rehab for midsubstance Achilles tendinopathy and provides a framework to help build tendon resilience across high-end movements.

Seattle Seahawks cornerback Richard Sherman (25) ruptured his Achilles tendon as he tackles Arizona Cardinals wide receiver John Brown (12), 2017. 

It’s human nature to associate pain with a problem, and for the most part, the absence of pain with health and function. For this very reason, end-stage rehabilitation can often be accelerated or overlooked. While there is an ever-growing body of evidence around initial tendinopathy treatment – something we’ll touch on by discussing phase 1 and 2 progressions – the focus of this article will be based around the later phase 3 and 4 progressions.

These progressions are of particular importance, as during these stages the tendon may often be only minimally painful, therefore reducing motivation levels to continue diligently following the program. And while this article is based on exercise prescription for midsubstance Achilles tendinopathy (tendinopathy symptoms that occur around the central part of the tendon, as opposed to insertional tendinopathy that occurs at the insertion of the Achilles tendon), the concepts and philosophies covered within this article can be adapted and tailored for tendinopathies occurring in various sites.

Tendinopathy overview

Tendinopathy can be a frustrating condition, particularly for those who compete in sports with little opportunity for rest or recovery periods. Tendinopathies have previously been associated with repetitive and overuse activities1, although the repetitive activity itself may not necessarily be the only underlying issue.

In the presence of movement dysfunction, this may be the case, but more recently tendinopathies have been linked to sudden spikes in loading that exceed the tendons tolerance2. Sudden increases in loading, regardless of the modality, can severely disrupt the tendon’s ability to heal3. For the most part, tendons are capable of maintaining equilibrium and adapting to increases in loads. However, if the rate of loading is greater than the tendons adaptive response, an acute episode of tendinopathy may occur.

Current Evidence-Based Treatments

A common misconception in treating tendinopathies is to cease all activities involving the tendon and unload the limb in an attempt to improve the condition. Unfortunately, this method does not aid in the repair of the tendon, nor does it help build tendon resilience. Cessation of all activity for an athlete often sets them up for future flare-ups and can decrease the load resilience of the tendon4.

Tendons are capable of tolerating loads, even in the acute phases of rehabilitation. Recent studies have shown isometric contractions for tendinopathies can have a positive effect on reducing pain5 6 7. Once the painful flare up has subsided, eccentric loading can be used to build tendon resilience providing pain levels do not exceed a score of 3 out of 10 on a visual analog scale (VAS)8.

The rating of 3,  usually refers to pain that is noticeable or distracting but can be managed and adapted throughout the session. It should not change movement mechanics. Therefore, center the management of tendinopathies around correct exercise prescription and loading principles rather than a complete cessation of activity.

Table 1: 4-phase progression of Achilles tendon loading
PhaseFocusCharacteristicsTime FrameKey Strength ModalityFrequencyPrescription Example
- Phase 1Acute/ProtectivePain/Stiffness upon wakening
Pain on palpation
Pain during activity
Difficulty performing 10 calf raises
0-2 WeeksIsometricsDailySingle leg Isometric Hold (heel off step) – Body weight x 20-40 sec x 3 sets

Progress to loaded holds
- Phase 2Load introductionPain/Stiffness upon wakening
Pain on palpation
Reduced pain during activity
Pain below a 4/10 when perfoming 10 calf raises
2-5 WeeksIsolated Resilience

Controlled Eccentrics
Daily to every second day (the heavier the load, the longer recovery time between sessions)Single Leg Calf Raises (heel off step) x (build up to 20 reps) x 3 sets
Eccentric Heel Lowers (heel off step) – 2 legs up, 1 leg down x 10 reps x 3 sets

Progress to loaded eccentrics and loaded calf raises
- Phase 3Strength AccumilationPain free upon wakening
Reduced pain on palpation
Minimal/zero pain with activity
Can perform 10 loaded calf raises
4-10 WeeksStrength Resilience

Reactive Stiffness
Every 2-3 daysSlow Prowler Push x 20 steps x sets
BB Step Up – Double Box x 6 reps x sets
Mini Tramp Jog x 40 sec ON: 20 sec OFF x 5 sets
Knee Drive Hold on BOSU x 20 sec hold x 4 sets
- Phase 4Elastic TolerancePain free upon wakening
Reduced pain on palpation
Pain free with activity
Jump rope pain free
10+ WeeksReactive Stiffness

Ballistic Stiffness
Every 2-3 daysLinear hop and stick; 6 reps x 4 sets
Lateral hop and stick; 6 reps x 4 sets
Linear hurdle and hop; 6 reps x 3 sets
Lateral hurdle and hop; 6 reps x 3 sets

(Note: Time frame is only a guide, there is a large variation in this within each case)

Table 2: Definition of terminology
IsometricsExercises characterised by no concentric/eccentric movement – designed to relieve tendon pain and build low level resilience (eg Iso Holds – off step)
Controlled EccentricsExercises characterised by a significantly higher load on the tendon during the eccentric portion – designed to build tendon strength and resilience (eg Heel Lowers)
Isolated ResillienceExercises characterised by an isolated loaded or unloaded concentric/eccentric movement – designed to build tendon strength and resillience (eg Calf Raise)
Strength ResillienceExercises characterised by a loaded concentric/eccentric movement – designed to accumulate the strength capacity of the tendon (eg Prowler Push)
Reactive StiffnessExercises characterised by low level instability and/or low level stretch-shortening cycle – designed to build low level tendon stiffness/elasitcity (eg Mini Tramp Jumps)
Ballistic StiffnessExercises characterised by high level instability and/or high level stretch-shortening cycle – designed to build high level tendon stiffness/elasitcity (eg Hurdle hop)

Loading phases (see Tables 1 and 2 for phase descriptions and definition of terminology)

Phase 1 – acute/protective

The length of an initial phase can vary in time because some athletes respond better, and their pain levels subside quickly, while others take longer to respond. The key focus in this phase is pain relief through the use of isometric exercises and the administration of Non-Steroidal Anti-inflammatory Drugs (NSAIDs) under the guidance of an appropriately qualified medical practitioner. Isometric exercises such as single leg holds off a step are an effective way to reduce pain levels. This position provides a comfortable place to start adding and progressing load. Isometric holds are to be built up to 20 seconds each leg initially, ensuring the discomfort doesn’t rise above a score of 3 out of 10. The aim is to complete 3 sets, 3-4 times per day as tolerated, and slowly building the hold time up to 40 seconds using the same guideline of no more than a 3 out of 10 pain score. As the set-rep times increase, the frequency of daily sessions can be reduced down to 1 or 2.

Progression onto phase 2 is characterized by a marked reduction in pain with activity and the ability to perform 10 calf raises per leg with no more than a 4 out of 10 pain score. Performed correctly, phase 1 will reduce a large amount of acute pain in the tendon and build some low-level tendon resilience.

Phase 2 – load Introduction

Phase 2 focuses on building strength in the tendon while reducing pain levels. If tendons fail to tolerate a load well, it may take as long as 72 hours post-exercise, to become painful – unlike traditional delayed onset of muscle soreness (48 hours). Being mindful of this window, it is therefore important to avoid large loadings within 3 days of each other. Building strength while reducing pain levels can be achieved through isolated resilience exercises such as single leg calf raises (Figure 1) and controlled eccentric training. Look to build single leg calf raises up to 20 reps per set while keeping pain scores to below 3 out of 10. Once the client has built up to 3 sets of 20 reps each side for calf raises, you can look to add loading, always monitoring any pain levels at the time and for subsequent days.

Figure 1: Single-leg calf raise

Figure 1: Single-leg calf raise

The introduction of controlled eccentrics within the same session is permitted once the client has achieved three sets of 10 unloaded calf raises. A good example of this is a double-leg calf raise up, then lowering for 5 seconds on one leg (Figure 2), gradually building up to 10 reps each side. Load can also be added to the controlled eccentric reps once 3 sets of 10 reps have been achieved. Progression on to phase 3 can be characterized by minimal to zero pain with activity and the ability to perform 10 loaded calf raises pain free.

Figure 2: Eccentric heel lowers (2-legged calf raise up, 1 leg lowers down)

Figure 2: Eccentric heel lowers (2-legged calf raise up, 1 leg lowers down)

Phase 3 – strength accumulation

Phase 3 is an important phase that is commonly overlooked or neglected as the tendon presents with minimal to no pain, and therefore is often assumed to have returned to optimal function. With the tendon relatively pain free, higher-end strength capacity becomes the focus along with introducing some reactive stiffness.

The Achilles tendon was designed to be used as a contributor to the stiffness of the ankle joint allowing for elastic energy to be utilised. Strength resilience exercises are utilised to further increase the strength capacity of the tendon and allow loading of the tendon in a dynamic yet controlled environment. The use of a slow prowler push (Figure 3) is a great way to pre-stretch the Achilles tendon by dorsiflexing the foot prior to foot contact. This removes muscle slack in preparation for generating force into the ground. This allows the Achilles tendon to be utilised in a semi-isometric state, while promoting force transfer prior to toe-off.

Figure 3: Slow prowler push

Figure 3: Slow prowler push

A double box step up (Figure 4) is another global exercise that allows the Achilles to aid in force transfer within the functioning system. Both of these exercises are great examples of integrating the Achilles tendon into global strength movements, whilst still having the focus placed heavily on the Achilles tendon. Phase 3 requires key exercises to integrate the Achilles tendon back into the global system via its contribution via the soleus/gastrocnemius complex through stiffness. Maximal to near-maximal loads should be utilised in this phase to allow the tendon to experience a high amount of tension and force transfer.

Figure 4: BB step up – double box

Figure 4: BB step up – double box

Also beginning in phase 3 are some lower-level reactive stiffness exercises. These exercises allow the tendon to be introduced to a more dynamic environment while keeping forces low and controlled. Mini tramp jogging (Figure 5) is perfect for this type of exposure. The trampoline has enough elasticity to allow the impact forces to be low, yet causes the tendon to act with stiffness, to create a series of stretch-shortening cycles (SSC) with the soleus/gastroc complex.

Figure 5: Mini-tramp jog

Figure 5: Mini-tramp jog

The use of the SSC is not the only stimulus that needs to be addressed in Phase 3 of rehabilitation. While the knee drive hold on a BOSU (Figure 6) does not require the use of the SSC, it forces the tendon to respond to a changing environment under the foot. While the forces are low level, it makes for the perfect introduction to a reactive environment while integrating the entire posterior chain. A plate held in different positions is used to manipulate the environment and force the body to continually react to maintain posture and stiffness. Progression into phase 4 can be characterised by being pain free on palpation, pain free with activity and specifically being able to jump a rope pain free for approximately 2 minutes.

Figure 6: Knee drive hold on BOSU

Figure 6: Knee drive hold on BOSU

Phase 4 – elastic tolerance

Phase 4 is focused on introducing the SSC in a more dynamic environment. Plyometrics are introduced and form the foundation of this phase. A good starting point is the linear and lateral hop and stick (Figures 7 & 8). These exercises allow both a linear and lateral component to the initial program by adding an explosive component, whilst not overloading the tendon with an aggressive SSC. These reactive stiffness exercises are essential prior to progressing in to ballistic stiffness exercises. Ballistic stiffness exercises begin to add more of a SSC component, along with higher landing forces, which are usually continuous in nature. These higher landing forces build stiffness in the tendon and therefore contribute to more efficient and effective tolerance to explosive movements. Linear and lateral hurdle hops (Figures 9 & 10) are perfect to start this progression, and to retrain the Achilles tendon to utilise elastic energy.

Figure 7: Linear hop and stick

Figure 7: Linear hop and stick

Figure 8: Lateral hop and stick

Figure 8: Lateral hop and stick

Figure 9: Linear hurdle hop

Figure 9: Linear hurdle hop

Figure 10: Lateral hurdle hop

Figure 10: Lateral hurdle hop

Key points
-Isometric exercises act as pain relief across all stages of rehabilitation

-3 out of 10 pain on the tendon site is acceptable during training

-Isometrics and isolated resilience exercises must be maintained during a weekly training program on an ongoing basis. Once in Phase 3 they can be completed 3 times per week

-Never remove all load from tendon, simply regress if needed

-Periodising loading is key – avoid sudden spikes in load

Conclusion

End stage tendinopathy rehabilitation is commonly overlooked or neglected. This article attempts to layout some of the end-stage options available to help safeguard the Achilles tendon against higher-end load exposure. There are numerous exercise options and variations for each category; the exercises listed here are just the tip of the ice berg, but act as a good starting point. When it comes to rehabilitation, Achilles tendinopathy is never a linear progression. It will flare up some days and feel great other days. The most important thing is to manage and periodise the tendon’s exposure to loads.

  1. British Journal of Sports Medicine, 48, 506– 509. doi:10.1136/bjsports-2012-092078
  2. Journal of Orthopaedic & Sports Physical Therapy, 45, 876-886.
  3. Journal of Physiotherapy ,60, 122–129. doi: http://dx.doi.org/10.1016/j.jphys.2014.06.022
  4. Best Practice & Research Clinical Rheumatology, 21(2), 295–316. doi:10.1016/j. berh.2006.12.003
  5. British Journal of Sports Medicine, 48, 506– 509. doi:10.1136/bjsports-2012-092078
  6. Best Practice & Research Clinical Rheumatology, 21(2), 295–316. doi:10.1016/j. berh.2006.12.003
  7. Sport Health, 32(1), 17-20. Retrieved from: http://0-search.informit.com.au.alpha2.latrobe. edu.au/documentSummary;dn=322863309596 697;res=IELHEA
  8. Journal of Physiotherapy ,60, 122–129. doi: http://dx.doi.org/10.1016/j.jphys.2014.06.022
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