What Is a “Tight” Muscle?

As anyone who knows me can assert by now, I have a big issue with vague definitions and overly subjective assessments.  Few things are worse in this regard than the infamous TIGHT MUSCLE.

You’ve seen various examples of it, I’m sure.  The trainer who says that you can’t get “deep enough” (whatever that is) in your squat because of “tight” calves.  The posture guru who claims that your pain is due to “tight” pecs and all of that computer sitting you do.  The Janda-influenced physical therapist (or the Eliot Hulses of the world) claiming that your pelvis is tilted “wrong” because of how “tight” your hip flexors and hamstrings are.

Unfortunately, even if there were something of merit to these people’s suggestions – a dubious proposition in itself – these cases are still all glossing over the task of actually defining tightness in a way that is logically consistent and meaningful.

Often, people are doing one of two things when they talk about muscles that they think are tight, and I'll address each separately: 

• They're talking about what feels tight to them, OR 
• They're assuming what's tight based on the positions of things they're looking at

To the first point: Proprioception is a weird thing, and the associated receptors that help with knowing where things are (muscle mechanoreceptors, joint receptors, skin pressure receptors, etc.) can have varying sensitivity, and that sensitivity can further vary in terms of how it is interpreted neurologically.  This is just within an individual in a particular set of circumstances, but this can further vary with the time, the environment, the person, the other neurological stimuli coming in at the same time, etc.  The point is that sensation is stupidly complicated, and it is often irresponsible to suggest that "feel is real."    

You might be able to recall instances when you *thought* your feet were in a certain position, or you *felt* like your shoulders were even (the examples go on and on), but once you looked at yourself in a mirror or checked your feet, you realized your body was actually positioned differently. Maybe you needed someone else to point this out for you!  This just illustrates how subjective our overall body awareness can be, and this extends to how our muscles feel.

Furthermore, I've trained people who have used "tight" to describe a sense that they don't want to go into a position because of something like a lack of control or -- even more commonly -- the muscle just hurt.  Think of when you're rocking some super gnarly leg DOMS (Delayed Onset Muscle Soreness) after your first day squatting in a month; you probably aren't trying to stretch as much, because those muscles are hurting like hell.  While you *may* also have some actual mechanical tightness occurring in those muscles (in terms of actual contraction that is limiting how far that joint can move), you're not likely to even find out how flexible you are since you're hurting too much to test it.  This is another major factor that muddies the waters when we talk about flexibility and "tightness."

Just because your yoga teacher says you look "tight" doesn't mean you are.  Just because you feel "tight" doesn't mean you are, either.  It's complicated.

To the second point: I'll be brief (at least compared to the previous point).  The simple fact is that you CANNOT TELL how tight or "weak" something is by a static assessment of someone's posture.  You can't even really tell by watching them move.  There are always numerous ways that forces could interact to create (or prevent) a given movement, and what you see when you observe a body is merely the net result of those forces; you don't actually know which muscle(s)/structure(s) was/were pulling or pushing in what ratio(s) to what other muscle(s)/structure(s). -- (Yeah, lots of parentheses there, but it felt necessary)

Think about how many times you've watched a person with "bad" posture get some "correcting" cue from a trainer, coach, therapist, etc.  What happened?  More than likely, that person simply... adjusted.  They pulled back those rounded shoulders, they raised their head up a little straighter, they tucked their pelvis a little differently, etc.  The point is that the person was able to do it without too much difficulty.

So if this is the case, and a person is able to adjust their bad posture with a simple cue or reminder, are the offending muscles really tight or weak?  Clearly the "weak" stuff is still strong enough to pull the joint(s) into the desired position.  Clearly the "tight" stuff is still able to relax enough to allow those positions to be achieved.  This is because in many cases, when we do see "deviations" in posture -- things which are usually pretty natural and are not usually cause for major alarm -- they're more a result of choice (even if it's unconscious choice) than they are something that is mechanically "off."

(There is a lot more to say, but things like "crossed syndromes" and posture are a pretty big can of worms that I would rather not get into right now; this post is long enough already).

But, Geoff -- what if the range of motion is truly mechanically limited?  What then, huh???What factors could contribute to this?

Here are some major ones to consider:

• Literal “shortness” of the muscle (not enough sarcomeres in series)
• Excessive stiffness of the tendon, musculotendinous unit, or other connective tissue
• Joint anatomy (bony blocks, etc.)
• Neurological “hypertonicity” of the muscle that causes resistance to the desired motion

In all but the last case, you’re probably not going to do anything significant about the limitation, regardless of how cool (or ridiculous) the mobility drills that you throw at it are.  The stresses required to make the fundamental structural alterations needed to overcome those first three scenarios range somewhere from "it's doable, but it'll take substantial force and very chronic exposure" to "practically impossible and maybe even dangerous to try."  Tissue *does* remodel in response to repeated mechanical stress, but we have to be careful about just how much remodeling we want to demand of those tissues.  In most cases, change in range of motion seem to be mediated primarily by neurological changes and associated motor behavior adaptations. 

In other words, we teach the nervous system over time to allow certain positions to be achieved and to tolerate certain loads that lead to increased range of motion.  How long that takes and the risks involved will depend on the specific motor task of interest, the body being trained, and many other circumstances.

So just remember that an apparent limitation in range, posture, etc. is not necessarily (or solely) due to a muscle that's doing something wrong.  Even if it is "tight," it may not be for the reasons you think, and it might not be something you want to correct.

*I may revisit this topic and examine stretching further as an extension of this write-up if there is interest.  So let me know!*

- G

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