Endeavour Rehab

Muscle Health: My Patient’s Muscles are Big but Weak – Why?

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Physiotherapist watching man perform squat|||

We all know that the size of a muscle is related to the strength that a muscle has. Bigger muscles are able to move bigger loads.

Anyone who has followed a consistent gym routine for a sustained period of time has experienced this for themselves. They would have seen noticeable improvements in their strength that came with visible increases in their muscle size.

But muscle size is far from the only factor in strength.

I had just tested the deltoid strength of a young and very fit patient dealing with shoulder issues.
I was easily able to overpower his resistance during the muscle test, clearly demonstrating that the muscle being tested was weak.
A student who was in watching the treatment asked:

“I don’t get it…he’s obviously very muscular so why is he testing weak?”

Physiotherapist testing strength of man's leg

The question, which was a good one, demonstrated a critical point in the understanding of muscle function and what has to happen in the body to move with strength.

While increased muscle size is needed in most cases to see big improvements in strength, weakness doesn’t necessarily mean a decrease in muscle size!

So what causes weakness if it’s not a loss in size? 

Physiotherapist testing the strength of a man's leg

In these cases, weakness is caused by an inhibition of the muscle.

An inhibition is the failure of the muscle to turn on to it’s full capacity. The muscles will appear weaker than they should be.

But how does a muscle become inhibited?

The mechanism underlying inhibition involves the function of the nervous system. At the root of this mechanism is a lack of connectivity, or disconnect, between the muscle, its nerve, the spinal cord, and the brain. 

Allow me to explain:

Muscles are turned on when messages from our brain travel down the spinal cord and then out through peripheral nerves that plug into the muscle (or innervate) we are trying to turn on.

That flow of information allows for full engagement of a muscle on command.

A strong muscle becomes weak when the flow of information is disrupted and connectivity is lost (usually between the spinal cord and the peripheral nerve/muscle).

This loss of connectivity happens for many reasons, not the least of which is old injuries which haven’t healed fully, tension in local and adjacent areas, and poor function of the spinal segments.

The important thing for patients and therapists to know is that the root cause of the gradual onset injuries or pain that our patients come in with is often the loss of connectivity and the resulting inability to properly activate a muscle.

The examples are endless – that patient with Achilles pain often has inhibition of the posterior chain muscles (glutes, hamstrings, calves).  Similarly back pain patients almost always have inhibited glutes. Many shoulder issues stem from poor activation of one or more of the many muscles that control the shoulder and scapula during movement. The list goes on and on.

It’s a simple concept:

As muscle control and activation diminishes, your movement changes. This puts more load on structures that are not used to or shouldn’t be loaded in that way, eventually leading to irritation or injury in that area. 

The big takeaway is to be aware of the potential for weakness from to muscle inhibition. It’s sometimes difficult to spot, but a good therapist will be able to find it and link it back to your movement pattern to better explain why you’re injured and what can be done about it.

At Endeavour use electro-acupuncture as the number one tool for re-establishing connectivity in the nervous system and restoring muscle strength. But there are other avenues, including movement training, rehabilitative exercises, and RedCord. 

Worry about first finding the therapist that can thoroughly explain your problem to your satisfaction. They are usually the ones that have the solution too.

Category : Understanding Physiotherapy