Lower Leg Pain From Running: Achilles Tendonitis Vs. Soleus Strain

Give Me The Fish (GMTF): Diagnosing a running injury is typically pretty easy. It gets a little more complicated when you start talking about soft tissue on the back of your leg. With a few simple tests and understanding the anatomy of how your leg functions, you can be on the right track to finding what is causing you lower leg pain and get you back to running.

While I recommend learning how to figure what you have first (this article), if you already know and need to get back on the road now, head to my article on the in-depth breakdown of how to get back to running in a little as 4 weeks after having Achilles Tendonitis or a Soleus Strain.

The Onset Of Lower Leg Pain From Running

As I’m ticking the miles away, I start to feel this lower leg pain forming in my right leg. Almost as if my calf is going to explode, except it’s not my calf. I’m just feeling this pain like it’s going to blow out my tendon, a couple of inches above the insertion point.

I kept thinking that if I just run a little bit farther it will ease out and be alright.

As I do this, I can’t help but think what an idiot I am. 

While there is a fine line between being hurt or injured. I had clearly passed over.

For the last few weeks, I was feeling this area tighten and a decrease in flexibility. I already knew I was training just on the border of “too much,” but like most of us, with no supervision, I sometimes think “it won’t happen to me”, or “pssh, I’m not average” and I kept training.

A couple of weeks down the road from the first sign of impending doom and only 4 weeks away from race day and my tendon feels like it’s about to explode out the back of my leg.

I keep running and the pain is just building. I make a quick stop, slam some ibuprofen, Tylenol, and a salt tab. Then I grit my teeth and slog through the last three miles, wrapping up my 30 mile run for the week.

The only problem, I can’t walk.

If this sounds similar, I encourage you to read on.

Lower Leg Pain: Achilles Tendonitis? Soleus strain? Calf Pull? What is it?

There are only so many injuries that a runner can accrue unless something catastrophic takes place. In terms of lower leg pain, most of these are pretty obvious.

Pain on the front of your leg… Most likely shin splints

Pain that feels like it’s inside the bone, especially if the impact hurts a lot, or even tapping it with something hard… Most likely a stress fracture.

Pain in soft tissue behind your leg… a little more complicated. That’s what we are going to break down today.

For everyone else, if you think you have shin splints, head here. If you think you have a stress fracture, head here. If you still don’t know… google it… or read below and learn more about the anatomy for what you may or may not have.

Is My Lower Leg Pain A Soleus Strain?

I’m going to start with what it’s not. It’s probably not your gastrocnemius.

Why do I say this?

Well, the gastrocnemius is what most people call “the calf muscle”. That’s the big piece of meat that is on the back of your lower leg. This muscle is actually not that super involved in jogging. It is when sprinting, jumping, and maybe if you run really on your toes, but it’s primarily fast-twitch, which means high explosive power, which means it’s unlikely the problem.

If you were doing these, then it is unlikely the Soleus.

The Soleus is a long muscle that runs behind your “calf muscle” a.k.a. behind your gastrocnemius.

The soleus is your “endurance muscle” as some people call it. It contracts and relaxes with walking and running, allowing you to essentially store up energy and then fire back as you move forward. It’s also primarily slow-twitch fiber which corresponds with its purpose.

There is also one major difference that matters when it comes to these types of injuries.

The Gastrocnemius spans two joints, the knee, and the ankle, while the Soleus only spans the ankle. We will talk about this importance a little later.

So, now that we know what a Soleus is, what is a Soleus strain?

A strain, as you probably know is just a gradient of torn muscle tissue.

Being sore is torn muscle tissue.

Having a pulled muscle is torn muscle tissue.

Having a strain is torn muscle tissue.

In slang terms, a strain is normally used as the middle ground between pull and sore.

There is one more part of this, which is important for understanding recovery.

Every muscle fiber in your body is one cell. You may have known this, but this is important when it comes to injury.

Keep this in mind as we talk about recovery later on.

What is Achilles Tendonitis?

A lie.

No, really. Achilles tendonitis doesn’t exist.

Why?

Because tendonitis means inflamed tendons and tendons can’t really get inflamed (they can a teeny tiny bit).

That’s the primary issue with injuries to this area.

It takes an incredibly long-time to heal because there is so little blood flow to the area and little blood flow means little resources. Little blood flow also means little inflammation.

But, for the sake of the interwebs and everyone’s sanity, we can keep calling it Achilles tendonitis and just know that we really mean, damage to the tendon.

To understand how this occurs, we have to understand how this tendon works.

This tendon connects from the insertion point on your heel to the origin points on your soleus and gastrocnemius. This tendon is known both as the calcaneal tendon and/or Achilles tendon.

While the tendon fibers themselves are from different muscles, since they are basically the same insertion, they are generalized as the Achilles tendon.

Tendons are extremely tough. They have to be because they are what transfer the pulling power of your muscles (muscles only pull) to your bones which allows you to move, kind of like a chain on a bicycle.

If you think about it, all of the weight in your body, plus the leverage it provides by you standing up or leaning forward, like when running, is all placed on your tendon, so in general, it’s pretty fricken durable.

According to the American Academy of Orthopedic Surgeons along with seeing the insane lifting power of today’s world record squats and deadlifts, we know the tendon can take thousands of pounds of pressure.

So, how does it breakdown?

External damage, and/or overuse, and sometimes a combination. In runners, it tends to be overuse.

Fortunately, like muscle fibers, unless something catastrophically happened (if so, none of my below stuff will likely apply to you) they don’t all normally go at once and we just have to repair the fray.

If the damage is bad enough, the tendon frays and stretches out like when you overstretch a rubber band. If you have ever gotten really into climbing, you have likely seen this on your hands or a buddy in the form of balled-up purple tissue at the base of the fingers.

Diagnosing Lower Leg Pain From Running

When I first got injured I wasn’t sure what I had. The problem is that low Soleus injuries from running can be confused with Achilles tendon injuries.

Knowing this and my limited time available due to my upcoming race and having lots of experience with doctors just telling me to rest and ice, I decided to opt-out and handle this myself.

Below are some of the indicators. I did not include ones for an Achilles rupture.

Why?

Because: you WILL know when that happens, to include LOTS of pain, loss of use of raising toes, you heard a snap or a pop, and/or feel a separation in your tendon.

Super different, right? (sarcasm)

Jokes aside, one pretty good indicator is a bump on the back of the tendon. You may or may not have that, but for me, it made it easier.

But, there is another test that you can do. Since we know that the Gastrocnemius spans both the ankle and knee and the Soleus spans just the ankle, we can isolate the muscle and test it.

When you bend a joint that spans a muscle connection point, you create slack in the muscle. This slack inhibits the muscle from contracting enough to produce force.

If you then do a calf raise with your leg straight and there is limited pain, then you do it again with your knee bent, you have essentially isolated your Gastrocnemius out because it has enough slack that it’s not being engaged.

With your knee bent, the only thing that is pulling/contracting is your Soleus.

So, Boom. You have a soleus strain. Otherwise, if you had felt lower leg pain when your leg was straight, it’s likely your Achilles tendon. Not always, but this is a really good guess and the best you will get without getting medical devices involved (ultrasound, MRI, scans, etc.).

How To Recover From Lower Leg Pain

Most injuries are healed and recovered in pretty similar ways. And, besides immediate damage control, rest and icing aren’t it.

Head to my article on getting back to running after Achilles Tendonitis or a Soleus Strain for an in-depth look on how to get back running.

But, if you do the below, you will be well on your way:

For a Soleus strain, do at least 180 reps a day of Bent Legged Eccentric Heel Drops.

For an Achilles tendon injury or Achilles tendonitis, do at least 180 reps a day of Straight Legged Eccentric Heel Drops.

It doesn’t hurt to do both if you still don’t know what you have, because it turns out that if you just train everything with both straight and bent legs, you cover all your bases and before you know it, your lower leg pain will be a thing of the past.

Until Next Time,

Coach T.