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Achilles Tendonitis: CALF RAISES WON'T SAVE YOU!

WHAT YOU'RE PROBABLY FEELING (what you wish you weren't)

  • Pain at the back of your heel; can travel up to the distal part of the calf -the bulge

  • pulling, aching, stabbing, sore

  • Can be worse in the morning and improves with movement/running

  • A lot of times, brought on by jumping into a zero drop shoe too much, too soon (I've done it)

  • Or brought on after hill repeats, speed workouts, increase in mileage

Starting off on the right foot:

Let's make a note in definitions.

  • Tendonitis: Inflammatory; acute (7-10 days)

  • Tendonosis/tendinopathy: degenerative; chronic, weakening (3 months)

  • Expected recovery: 7 days to 6 weeks. (it all depends)


"Tendinopathy is a common clinical syndrome characterized by pain, localized or diffuse swelling, and dysfunction. The main pathological conditions related to tendinopathy include tendinosis and peritendinitis, which are characterized by collagen disorganization and fiber breakdown, increase in mucus matrix, ingrown nerves and blood vessels, local swelling, and inflammatory cell infiltration."

Why this matters:

  • Your body isn't always neat and tidy when it comes to repair. It throws down the repair building blocks and then sorts it out later. Maybe. Sometimes. With the right amount of load (aka exercise).

  • It's very common (and normal) for there to be inflammation present during this process. And we want blood vessels and nerves in the mix to provide nutrients to the area and information from the affected area, but we don't want it ingrown.

  • Could this disorganization be a reason for prolonged pain in that Achilles area?


What You've been told BEFORE:

"The etiopathogenesis of AT remains unclear but is currently considered multifactorial, and an interaction between intrinsic and extrinsic factors has been postulated.

Changes in training pattern, poor technique, previous injuries, footwear, and environmental factors, such as training on hard, slippery, or slanting surfaces, are extrinsic factors that may predispose the athlete to AT. However, also dysfunction of the gastrocnemius soleus, age, body weight and height, pes cavus, marked forefoot varus, and lateral instability of the ankle have been reported as risk factors"


  • What we talked about above, too much; too soon

  • Running an banked roads

  • The zero-drop shoe monster got you

  • Potential foot and ankle weaknesses

A NEW Reason WHY Achilles Tendonitis Happens:

"AT is an overloading injury and although its aetiology is multifactorial, deficits in muscle performance is suggested to be a key factor, which seems to be maintained long after symptomatic recovery."

"Several lines of evidence suggest that neural changes to the triceps surae might underpin some of these chronic motor deficits In particular, it has been shown that individuals with AT have:

(a) lower contribution of gastrocnemius lateralis (GL) to produce plantar flexor force Crouzier et al. 2020 and

(b) greater levels of intra-cortical inhibition associated with lower plantar flexor endurance during single leg heel raise test when compared to controls.

Collectively, these findings suggest that changes in how the central nervous system control muscles coordination within the triceps surae (force distribution and activation) might impact load distribution to the tendon in individuals with AT. This is of particular importance because altered triceps surae coordination (due to lower individual muscle contribution to muscle force) could create uneven loading of the Achilles tendon and contribute to tendinopathy."


(we're doing something new: I'm using the paper's abstract to help explain things…)

"Deficits in muscle performance could be a consequence of a reduced ability of a motor neuron to increase the rate in which it discharges. This study aimed to investigate motor unit (MU) discharge properties of each triceps surae muscle (TS) and TS torque steadiness during submaximal intensities in runners with Achilles tendinopathy (AT)."

"MU mean discharge rate was lower in the gastrocnemius lateralis (GL) in AT compared to controls. In AT, GL MU mean discharge rate did not increase as torque increased from 10% peak torque to 20%."

"Our data demonstrate that runners with AT may have a lower neural drive to GL, failing to increase MU discharge rate to adjust for the increase in torque demand. Further research is needed to understand how interventions focusing on increasing neural drive to GL would affect muscle function in runners with AT."

Think of a motor unit as an engine (it's the nerve and the all the muscle cells that nerve plugs into).

Example: you have 100 engines and have 100 units of work that need to get done.

Ideally, that work would be distributed evenly amongst all the engines.

No problem!


Only half your engines worked.

Now, each engine has to do 2x the work it's supposed it! It can handle it; it can survive overdrive, but it's not meant to "live" in overdrive.

You need all your calf "engines" running and to have them performing optimally.

Specifically in the case of Achilles issues, it’s the lateral gastroc, or the "outside" calf head that isn't performing like it should.

So you can do calf raises for DAYS!

But if only "half your engines" are working, they're not going to help.

Getting more specific, you're continuing to only strengthen or work the motor units that are already "on."

Doing more calf raises, is just doing more.

It's NOT fixing the problem.


It's not a reason to panic or lose hope.

This new way of looking at it, can help explain why you're not seeing the response you want despite your hard work.

It's not that your lazy.

You might even be doing the right exercises, but if the message isn't getting through, and the engines aren't turned on…then more is just more.

Don't worry-we're going to keep exploring together the WHY AND HOW TO FIX Achilles tendonitis in upcoming videos and blogs.

Stay Tuned!

If you want a head start: go check out my Stronger Feet Workshop.

I've used these exact exercises in the clinics COUNTLESS TIMES with great results for running patients with achilles tendonitis, plantar fasciitis

Until next time…

Dare to Train Differently,

Marie Whitt, PT, DPT //



Lower motor unit discharge rates in gastrocnemius lateralis, but not in gastrocnemius medialis or soleus, in runners with Achilles tendinopathy: a pilot study

Bibliometric Study of Exercise and Tendinopathy Research from 2001 to 2020

Management of Achilles and patellar tendinopathy: what we know, what we can do.

Efficacy of heavy eccentric calf training for treating mid-portion Achilles tendinopathy: a systematic review and meta-analysis

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