Achilles Tendinopathy is a common injury in runners and other athletes. It is generally classified as localized pain in the tendon and/or heel that is worse with increased loads through the tendon (a heel raise hurts more than standing, hopping feels worse than heel raises). People also usually report their symptoms are worse in the morning during the first few steps right after getting out of bed. Although this condition has historically been known as a “tendinitis”, it is now being referred to as “tendinopathy”. The suffix “itis” means “inflammation” and in this condition, there are generally no inflammatory cells present and causing the symptoms. Rather, it is more of a reactive process to overload. Tendinopathy refers to any problem within the tendon and its cells, and is therefore a more fitting name than tendinitis.
Insertional vs Mid-Portion Achilles Tendinopathy
There are two different forms of Achilles Tendinopathy and it is important to know the difference
between the two of them because some of the exercises vary slightly for each. In Insertional
Achilles Tendinopathy, there is generally pain where the Achilles Tendon inserts on the
calcaneus (the heel bone). Performing a calf stretch, walking barefoot, squatting, and uphill
walking may all be aggravating factors. In Mid-Portion Achilles Tendinopathy, the pain is
generally located 2-6 cm above the heel. Aggravating factors may include running, heel raises,
and hopping. If you think you may have Achilles Tendinopathy, it is important to have a thorough
evaluation by a Physical Therapist so that they can rule out other potential causes of your pain,
and help design an individualized rehabilitation program for you based on the Stage of
Tendinopathy you are currently presenting in, what your personal goals are, what type of
Achilles Tendinopathy you have, and any other biomechanical or movement issues that need to
be addressed.
What causes Achilles Tendinopathy?
The single greatest cause Achilles Tendinopathy is training errors. Sudden increases in activity,
mileage, speed, incline running, changing stride or cadence can all lead to tendinopathy.
Remember, your body is always in a balancing act of load/wear and rest/repair. Increasing
training load or activity too much without enough rest can tip your tendons too far towards the
load/wear side of the spectrum and can cause tendinopathy. A good, general rule of thumb to
follow is to not exceed increases in training load by more than 10% each week. That means that
if you have been able to comfortably run 20 miles per week for the past month, then you can
increase your next week’s mileage to 22 miles without increasing your risk of injury. Of course,
each person is different and it is therefore advisable to track your training load with the help of a
Doctor of Physical Therapy or Personal Trainer to make sure you are progressing in a safe and
gradual manner.
Some other risk factors for Achilles Tendinopathy include a previous history of Achilles
Tendinopathy, recent injury, age, gender, muscle power/strength, poor dorsiflexion, excessive
pronation, and weight gain. Another risk factor that often goes unmentioned is taking antibiotics
from the Fluoroquinolone family. These medications are used to treat a range of illnesses
including respiratory infections and urinary tract infections. Some of these medications
commonly prescribed are Ciprofloxacin (Cipro), Gemifloxacin (Factive), Ofloxacin (Floxin),
Moxifloxacin (Avelox), Levofloxacin (Levaquin), and Norfloxacin (Noroxin). This risk increases
with higher dosages of the medication. When compared to other classes of antibiotics,
fluoroquinolones demonstrate a 3.8-fold greater risk of developing Achilles
tendinopathy/rupture. Patients treated with fluoroquinolones have a 1.3-fold increased risk of
tendon rupture compared to those not taking them, and that risk increases to a 46-fold greater
predisposition if patients are also exposed to corticosteroids simultaneously. Age greater than
60 also seems to increase the risk of tendon rupture with fluoroquinolone use. If you have
recently taken, or are currently taking any of these medications, ask your Physician or
Pharmacist for information about the increased risk of tendon ruptures while on these
medications. It is also important that you tell your Physical Therapist and Personal Trainer if you
are on (or have recently been on) any of these medications so that the necessary load
modifications can be made.
The body is constantly in an equilibrium between load (or use)/wear and rest/repair. Whenever
you perform a bicep curl, for example, you are applying load to the bicep muscle and tendon.
Throughout the performance of the curls, the bicep is subjected to loads which cause micro
tears within the muscle belly. When you are done working out, and give your bicep time to
recover, those micro tears begin to repair and then become adapted to the loads you have just
subjected them to. The key here is that you must give your body ample time to recover between
bouts of loading. The same is true in all bodily tissues. When you apply a given load, there is a
period of wear and then the tissue needs time to recover and repair during which time it
becomes adapted to handle the loads you applied to it. When the scale begins to tip too heavily
towards the load/wear side without enough rest/repair, the tissues you loaded are at an
increased risk of injury. In tendinopathy, when tendon loading exceeds the tendon’s capacity
(you ask it to do more than it is able to at that particular point in time), without sufficient rest, it
develops into a tendinopathic tendon which then becomes less capable of handling load.
The Stages of Tendinopathy:
Before delving into how to treat Achilles Tendinopathy, it is important to understand the different
stages of tendinopathy. These stages are classified differently, but they are really more of a
continuum with load being the main driver along the spectrum.
The Reactive Stage:
The Reactive Stage of Tendinopathy is the tendon’s immediate response to overload. It can be
painful and irritable in this phase. This is something that many people have experienced. If you
have ever spent a day walking around Disney Land and then noticed by the end of the evening
or the next morning that your heel or calf feels “tight” or “stiff”, then you have experienced the
Reactive Stage of Tendinopathy. This stage is completely reversible and is your body’s way of
telling you that it was asked to do a little more than it can currently handle, and now needs time
to rest and recover. This stage is also commonly seen in youth or novice athletes, or whenever
someone takes some time off of their normal workout routine, and then tries to jump back into it
again. In this stage, load management is key, and isometric exercises can help decrease pain
and improve the muscle and tendon’s ability to handle loads (more on isometrics later).
The Disrepair Stage:
The Disrepair Stage of Tendinopathy is when your tendon has already experienced that initial
Reactive Stage, but load was not managed appropriately and now the tendon is going through
actual structural changes. You may experience pain and irritation with exercises above a certain
threshold. For example, heel raises might not bother you, but any kind of hopping or jumping
does. Or maybe you can run 3 miles just fine, but once you hit mile 4 you start to feel symptoms
in your heel, Achilles Tendon, or calf. Typically this stage is seen in older athletes, or in people
who chronically overload their tendons without giving them sufficient rest and repair. In this
stage, load management again is key, along with specific exercises for your current tissue
capacity and goals.
The Degenerative Stage:
The Degenerative Stage is characterized by further changes to the structure of the tendon, and
now the development of areas of the tendon that are completely unable to bear any load. Once
areas of the tendon are in this stage, it is irreversible. That however, is not a tendon death
sentence. What we now find in tendons in the Degenerative Stage is that although there are
areas of the tendon that can no longer bear load, the “good” or “healthy” areas of the tendon will
actually begin to lay down more “good” and “healthy” tendon tissues leading to a thickening of
the tendon. Therefore, even though these areas of irreversible tendon degeneration cannot
simply be “fixed”, your tendon begins to adapt with proper and sufficient loading and will
increase its cross-sectional area with more tendon tissue so that you can still participate in your
activities. The key here is that the loading has to be done gradually and progressively so that
the tendon is loaded enough to cause positive adaptation, but not so much that it is unable to
recover. When a degenerative tendon continues to be chronically overloaded, it can lead to a
complete tendon rupture which most often requires surgical intervention and a very lengthy
rehabilitation process.
Treatment of Achilles Tendinopathy
The treatment plan always depends on the Stage of Tendinopathy, patient activities and goals,
whether it is insertional or mid-portion, and other deficits noted in the kinetic chain. Generally,
there are four stages to Achilles Tendinopathy Rehabilitation:
Phase 1: Isometric Loading
In this phase, the goal is to reduce tendon pain, facilitate movement, and reduce fear
avoidance. The isometric loading protocol includes 5 repetitions of 45 second isometric holds.
An isometric hold is when the muscle is contracting, but no movement is being performed. For
example, an isometric exercise for an Achilles Tendinopathy would be to go up onto the toes
and hold a heel raise for 45 seconds. After a 2 minute rest, repeat the 45 second isometric hold.
You should be able to work up to 5 repetitions of this. Since gradual progression of load is
important in the treatment of tendinopathy, you can progress this isometric hold by either
holding weights like dumb bells in your hands and increasing the weight as tolerated, or by
pushing into a wall as you hold a heel raise. You should work up to about 70% of a maximal
effort contraction in your calves. Begin in this phase if you are currently in the Reactive Phase of
Tendinopathy, or if trying to perform a heel raise causes more than about 4/10 pain in your
Achilles Tendon. It may also be wise to work in this phase if you are an athlete who is currently
in season and needs to be able to get through the season without an increase in pain. As soon
as your season ends, however, be sure to progress through the next Phases of Rehabilitation.
Phase 2: Isotonic Loading
This phase is meant to restore muscle strength and hypertropthy. There are two different
protocols for Isotonic Loading. One is Heavy, Slow Resistance (HSR) and the other is the
Eccentric Protocol. HSR consists of 3-4 sets of 15 repetitions performed 3-4 times per week. It
is performed by doing both the concentric and eccentric portions of the lift for 3 seconds each.
Some exercises may include squats, leg press, hack squats, and heel raises for Achilles
Tendinopathy. For example, in a heel raise, you would take 3 seconds to lift up onto your heels,
and then 3 seconds to lower your heels back down. It is helpful to use a metronome to time the
exercises correctly (you’d be surprised how hard it is to stay focused on counting 3 seconds up,
3 seconds down for 15 repetitions!).
The Eccentric Protocol consists of 3 sets of 15 exercises performed twice per day, every day. It
is performed by doing heel drops only (the lowering part of a heel raise) for a count of 3 seconds
each, beginning with body weight, and progressing the weight as tolerated. As the name
suggests, this protocol is focused on the eccentric phase only.
Both protocols are meant to be implemented for 12 weeks and have been shown to have similar
long-term outcomes for pain and function. The Eccentric Protocol may be a little more irritating
and cause increased muscle soreness in some people; it is also much more time consuming to
follow the Eccentric Protocol. On the other hand, the HSR Protocol has been associated with
higher levels of compliance and satisfaction, but requires gym equipment.
Phase 3: Energy Storage Loading
In order to reach this phase, it is important to have already established a good strength basis.
This phase is highly individualized based on patient activities and goals. It consists of various
hopping, jumping, landing, acceleration, deceleration, and change of direction tasks. Initially, it is
helpful to train bunny hops, forward and backward line hops, side-to-side line hops, and then
multidirectional and rotational bunny hops. After training those movements, more sport and
activity-specific training can be added to the program.
Phase 4: Return to Sport/Activity
In this phase, you may be able to participate in modified or full training sessions/activities,
decreased time or different roles in a game/match/competition, but you are not yet
playing/competing/performing at your desired level. This might mean that you have gone back
to running, but you are not running at your desired speed or for your desired mileage quite yet. It
is absolutely crucial that this stage is managed appropriately with gradual, progressive
increases so that you do not put yourself at increased risk for another flare up of tendon pain or
any other injury.
How does exercise help my tendon pain?
Whenever exercise is prescribed, it is done in a specific way to utilize mechanotransduction.
Mechanotransudction is essentially applying a mechanical stimulus into a biochemical response
in the body that leads to a desired adaptation in the targeted tissue. For example, when
performing a heel raise, the mechanical stimulus is the lifting of the heel off the ground. This
causes the calf muscle to contract. When the muscle or tendon cells contract it induces a
chemical response within the cell that triggers a cell to cell communication network. Mechanical
stimulus of one cell can thereby influence nearby cells which did not directly receive the
stimulus. Tendon cells (called tenocytes) respond very favorably to controlled loading via
mechanotherapy (the application of mechanotransduction to exercise prescription). Tenocytes
need a mechanical stimulus (load) to tell them what to do. When there is an appropriate
stimulus or load, the tenocytes are able to respond by becoming more capable of handling
increasing loads. If they are pushed too far too quickly, however, without the appropriate rest
and repair time, then they begin to become overused and potentially triggers the tendinopathy
continuum. Tendons, therefore, need to be pushed in order to adapt to increasing demands, but
in a structured, planned, intentional, and gradual manner.
References available upon request