#008 Achilles tendinosis pain and what to do about it

The classic Achilles tendinosis pain occurs as a result of long-term micro-tears of the Achilles and these occur due to repeated high impact

This picture depicts the problems that your Achilles can suffer

We are going to discuss Achilles tendinosis. If you have other problems, it’s best to talk to your health care provider…

Executive summary and video

While there are a number of Achilles conditions, Achilles tendinosis is the most common and what works to prevent and treat this will work to prevent and treat all.  The classic Achilles tendinosis pain occurs as a result of long-term micro-tears of the Achilles and these occur due to repeated high impact.  Jolt is a good word for high impact so we will use the term jolt in this article. 

Video: Seated foot exercises to enhance your foot and heal your Achilles

Achilles tendinosis described

With Achilles tendinosis you feel pain in the Achilles 2-3 cm above where it inserts on the back of the heel.  Often the pain happens when you get out of bed or chair, or start walking or running.  You may warm out of the pain only to feel it return when you’ve exercised enough to make affected body parts tired.  Achilles pain goes together with pain in the calf muscles.  So if you look for pain in your calf muscles  - by doing stretches and massage - you will find that pain and you can do something about it.

Achilles pain often affects over 45-year-olds because the older you are, the longer your history of damage, scarring and imbalances, and the slower your tendon healing.   Tendon strains heal slowly even when conditions for healing are perfect.  Achilles pain happens frequently in gymnasts and to a lesser extent, in all athletes (ref. 7).  This is due to repetitive high-impact loading that causes a strain that worsens over time, and which takes a long time to heal. 

Active people suffer Achilles tendinosis strain pain and tendinopathy whereas inactive people suffer Achilles tendonitis and rupture.   The latter is due to a lack of conditioning of the tendon that makes it more likely to catastrophically fail. You go to play a family game of cricket or softball. The moment you hit the ball and start running you feel something like a kick in the calf and are no longer able to push off the injured leg.  A rupture has occurred that may require surgery.  Either way, it is the same cause.  There is a jolt, and it causes a tear.  

Hard to link Achilles tendinosis with foot posture

Researchers find it hard to link foot posture to Achilles tendinosis pain and this is because they have up until now been looking in the wrong place.  Since 2018, ultrasound technology has enabled researchers to look in the right place and they have now been able to assess the size and thickness of lower leg and foot muscles to accurately determine which muscles are weak and lazy in Achilles strained athletes, and which muscles (or areas of muscles) are too strong or too tight (refs 3,4,5,6).

Armed with a knowledge of which muscles are weak we can strengthen them. And armed with a knowledge of which muscles or areas of muscles are too tight or too strong, we can use them less, and we can stretch and massage them. This all aids in better function and control, so that the Achilles operates in a smoother less jolting environment.  Also as a side benefit your body works with increased control and power out of a more stable base of support.

Five faulty patterns of muscles activation

There are three locations where muscles are weak and underactive and two locations where muscles and tissues are tight and/or over-active.

The underactive and weak muscles and their locations:

The small muscles that narrow the front of the foot and press the mid-toes into the ground are weak.  This reduces the springiness and control of the foot which means that the foot slaps down at “heelstrike” and puts a jolt through the Achilles.

The toe and front of foot lifting muscles (dorsiflexors) are weak and lazy, which leads to a “slap down” of the foot at footfall, which jolts the Achilles and calves.

The plantar foot structures (in the sole of the foot) are thinner and weaker.  This means that they are less springy, less able to lift the foot arches, and less able to prevent jolting to the Achilles and calf muscles.

The overactive and tight muscles and their locations:

The toe-curling muscles (flexor muscles) are over-developed and do too much work.  This creates a longer foot lever and a loss of fine control.  We don’t want to stop using them however, just use them less.

Tight bands and scar tissue in the calf muscles and their associated connective tissues.   The calf muscle complex is known as the Triceps surae.  It’s a complex system of four different muscles, all of which require the right kind of nurture and maintenance if they are to function well.  We shall now devote a subsection to the anatomy of the calf muscles.

Anatomy of the calf muscles

Picture 1:
dissection of the Triceps surae: a complex muscle that potentially can develop unequal patterns of loading
(Attribution via Wikimedia Commons)
Picture 2:
the feather-like arrangement of the calf muscle fibres and aponeuroses (Attribution)A huge force…
The contractile muscle fibres are drawn as diagonal lines in the left-hand diagram (picture 2).  The fibres are described as “pennate”, which means that the muscle fibres and aponeurosis together look like a bird’s feather. The pennate arrangement means that there is a huge cross-sectional area of muscles fibres – much bigger than the cross-section of the calf, which means that the calf muscle exerts a huge force through the Achilles - albeit over a shortish range of movement.A force that may not be equal across the whole width of the Achilles…
Each area of the calf muscles funnels into a specific area of the calf muscle aponeuroses and from there into the Achilles tendon.  (An aponeurosis is a dense sheet of connective tissue that looks like the protective tissue that surrounds a nerve; an aponeurosis connects a muscle or muscles to a tendon).

The calf muscles are not a uniform structure

As you can see from the first picture, the muscles of the Triceps surae (the calf muscles) are never 100% uniform, and different areas of the Triceps surae may be either weak or tight due to scar tissue and trigger points.  This would mean that the Triceps surae pulls unevenly on the aponeurosis and the Achilles.  Since the Achilles is now unevenly loaded some areas of it are more likely to sustain damage from the repetitive jolts of sporting activities.

This is why it’s important to regularly perform exercises, stretches and massages that optimise the weaker and or tighter areas in the Triceps surae.

Possible heat spots in the tendon

If a tendon temperature rises above 45 degrees (and experimental models suggest it might),  this would slow the healing of the Achilles and prolong any injury (ref 11 12).  If however we can smooth the shocks and jolts, the heat generation and temperature would not rise so high.

How do you picture your foot?

As a Pilates instructor, I give movement instructions for feet and ankles and clients often can’t immediately comply. That’s perfectly all right, because “Rome wasn’t built in a day”, and “first it’s hard and then it’s easy”.  The movement eventually appears, and foot ankle and knee health improve.

With a more correct picture of your foot it becomes easier to learn the muscle strengthening exercises that turn your foot into a superb spring-loaded, “spoke-and-arch” shock absorber, just like it was meant to be, and this will reduce the jolts and jarring on the Achilles!

A wrong view: “the foot is like a plank with an ankle at one end and cat’s claw toes at the other”...

I believe that most of us see our foot as a plank of wood.  The back end of the plank attaches to a hinge (the ankle joint), and the front end of the plank attaches to toes that curl like a cat’s claws.  This picture is incorrect:

The ankle joint is actually a third of the way forward from the back end of the “plank” (the back of the heel) and two-thirds back from the front of the plank (the balls of the toes).

Yes the toes can curl like cat’s claws, but they do other things like press their mid-portion into the ground, spread apart, squeeze together, and lift away from the ground.

The third and perhaps most important misperception is that the front half of the “plank” is passive and inactive.  Nothing could be further from the truth -the front half of your foot can be very strong and responsive if you make it so – not like a plank at all!

A more correct view: the foot is like five spokes of a wheel whose centre lies under the ankle, and over the front end of the heel bone: 

The front ends of the spokes are powerfully pulled together by small muscles: the interossei and the big toe adductors 

Other muscles act on the spokes like an archer’s bowstring: the spokes bend and form arches!

These muscles are the key muscles that cushion your foot-to-ground contact and take the jolts out of your foot placement.

How to heal your Achilles – summary first

We need to stop the jolting and jarring on the Achilles and give it a healing stimulus. Here are the healing strategies:

(1) Reduce the Achilles jolts and shockwaves with hill walking
You can always walk uphill sideways and use walking sticks.  There is evidence that this works (references 8 and 9).

(2) Strengthen and enhance the muscles that are known to be weak and lazy in people who suffer Achilles pain
If we bring the lazy muscles up to full strength, it is like replacing the springs and shock absorbers in a car. There’s a smoother ride and there is less damage to the Achilles.

(3) Exercise your Achilles and calves in a way that will help them to heal
Exercises that heal the Achilles and calf muscles use constant loading with no jolting.  If the healing is to get ahead of the damage you need to do them most days.

How to heal your Achilles – more detail

1. Make the deepest foot muscles work
   The muscles that narrow the front of the foot and press the middle of the balls of toes into the ground add springiness and cushioning to the forefoot so that it doesn’t slap down at foot strike and add to the jolting of the Achilles.

Picture: the deep foot muscles

2. Make the dorsiflexors work
   The toes must dorsiflex at footfall and at toe-off. If the toes are lifting at the moment of footfall the foot and ankle are braced and springy (try it!). As soon as the foot has landed the toes no longer claw into the ground and by reflex the “narrow-your-forefoot muscles” pull your forefoot together and activate the foot arch muscle (try it!).  The foot is now a rounded rocker and there is a reduced lever action with a smoother load on the Achilles.

Picture:
dorsiflexion and the action and the muscles that perform it

3. Normalise the calf muscles and sole of foot muscles
   The weakest and/or tightest parts of the calf muscles need massage and smooth eccentric contraction to bring them back up to full normal function. Only then will the whole Triceps surae deliver equal load over the whole Achilles tendon. A side effect of this is that the calf muscles will have more strength at their longest length where they most need it, to prevent calf tears and Achilles injury.

4. Put a healing stimulus into the Achilles
   The best healing stimulus for tendons and connective tissues is to static load them. We do this by spending time with minimal movement, standing on one leg with the heel off the ground and weight mostly on the balls of the toes.

If you do all the above muscle work your Achilles will get a good healing stimulus to help it rebuild and re-align its collagen fibres, and the gentle rhythmic movement will also bring nutrition into, and send waste and inflammation out of, the tenocytes (the cells in the tendon). You can expect some good results.

This article focussed on building your awareness of muscle activity - how they are imbalanced in Achilles pain sufferers and what sort of "aware" movements and exercises will correct the imbalance.

The next article will introduce more exercises, all of which will efficiently and enjoyably enhance your foot and ankle muscles. so what started out as fixing an Achilles problem will improve and enhance your walking and running!"