How to Identify Muscle Imbalances and Muscle Dysfunction


Use functional training to root out and repair these key causes of chronic pain and movement impairment.

Table of Contents

Matt Hsu lifts his right leg to demonstrate balanced adductors and abductors.

Are your adductors and abductors balanced?


You probably came here because something in your body doesn't feel right. You probably have chronic pain in one or more joints.

You came across this "muscle imbalance" term and are pretty sure it applies to your achy-breaky body.

I've been in the same situation. I suffered for years with chronic pain in my back, hands, wrists, shoulders, hips, knees, and feet. Conventional medical advice and physical therapy were a dead end for me. Acupuncture, chiropractic, and massage all failed to give me lasting results.

What gave me freedom and confidence was learning how to move my body right. As I started to move right, I started to feel right. 

In this article, I’m going to tell you what I think “right” movement is, define muscle imbalance and dysfunction, and show you how to identify both.


Types of Muscle Imbalances

Let's start with the basics. Muscles are the organs of physical integrity and movement. Without your muscles, you would be a sack of bones and blood stuck on the floor.

Muscle imbalances come in two general flavors: joint muscle imbalance and symmetry muscle imbalance.

In both cases, you’re comparing the achievable length and strength of the muscles in relation to their maximum anatomical length and the functional demand and range of motion required for the task at hand. You are trying to control movement with the right balance of flexibility and strength, and without experiencing pain. 

Joint muscle imbalance

This form of imbalance happens in muscles  on either side of a specific joint (or joints). 

The problem happens when the muscles on either side of the joint can’t work together to produce a movement or maintain a position. 

The imbalances occur when muscles on one side of the joint aren't as strong or as extensible (able to get longer) as they need to be to accommodate what's happening on the other side.

Length and strength are both crucial considerations. Sometimes muscles are too short, and sometimes they are too weak in a given length or position. Most of the time, it's a combination.

And the result is often a loss of range of movement and pain.

Here are a few examples of joint muscle imbalances:

  1. The length and strength of the hamstrings are not proportional to the length and strength of the quads, affecting the knee joint.

    Matt Hsu bends his right leg to demonstrate balanced hamstrings and quadriceps.

    Are your hamstrings and quadriceps balanced?

  2. The strength of the inner thighs to create adduction is not proportional to the strength of the outer hip to create abduction.

    If you’ve been doing Instagram influencer booty workouts, you may have strong outer thighs and hips, but weak inner thighs. This does not create a functional, balanced body. Having weak, atrophied inner thighs will make life a lot more challenging in the long run and likely cause knee pain.

     abductor vs adductor muscle balance
    Are your adductors and abductors balanced?

    A meme of a model on the runway, with no muscle definition.
    A lack of muscle can cause joint pain. Original photo by Christopher Macsurak

  3. The length and strength of the anterior abdominal musculature (your abs!) is incongruent with the length and strength of the lumbar and thoracic spine extensors (the muscles along your spine). This is an example of how joint muscle imbalance can involve multiple joints and can result in back, hip, and knee pain.

    Mat Hsu demonstrates an imbalance between abdominal and spinal extensor muscles.
                   Abs not strong enough to counter spinal extensors? Or spinal extensors not able to lengthen?

  4. The length and strength of the  hip flexors does not match the length and strength of the butt muscles.

For example, someone can have extremely strong hip flexors that are great at creating hip flexion, but very poor at lengthening. They can also have glutes that are weak and unable to generate hip extension. This would be considered a muscle imbalance. The muscles that perform one motion are far stronger than the muscles that create the opposite motion.


Mat Hsu demonstrates good hip flexion.

Good hip flexion


Mat Hsu demonstrates poor hip extension.

Poor hip extension

Symmetry Muscle Imbalance

The second category of muscle imbalance is symmetry imbalance. This is when we compare the same muscles on the left and right side of the body.

Here are a few examples of symmetry muscle imbalance:

  1. The quadriceps muscle group on the right leg is stronger and longer than the same muscle group on the left leg. Many people have a glaring asymmetry in their thighs, with one side clearly thicker or stiffer than the other side.

    Matt Hsu demonstrates a quad stretch with the support of a chair.
                                    Most people find this stretch much harder for one leg than the other.

  2. The muscles on the right shoulder and the right side of the neck are a different shape, size, and strength than the muscles of the left shoulder and left side of the neck.


In this video, you see the right side of his neck muscles do not contract as much and are much flabbier than the left side. 

Now that you know what joint muscle imbalances and symmetry muscle imbalances are, let's talk about why they matter.

See also: How do you fix repetitive strain and overuse injuries?


Why do Muscle Imbalances Matter?

Muscles determine the resting position, and range and path of motion for your bones. If you want your spine to assume a certain orientation, you do it with muscles. If you want to grab something overhead, you do it with muscles. If you want to stand up from a chair or go for a run, you do it with muscles.

Never forget: muscles move bones.

When muscles are imbalanced, it negatively affects resting position, range of motion, and path of motion, making it difficult to perform athletic endeavors and even the activities of daily life. 

When you have a joint muscle imbalance, you may feel jamming, pinching, or achy sensations near a joint. You will notice certain motions become completely inaccessible no matter how hard you will your body to do them. Your repertoire of movements becomes constrained. Left alone, these constraints fester and limit you further.

When you have a symmetry muscle imbalance, your body is set up for serious frustration. This type of imbalance can lead to joint muscle imbalances and [muscle dysfunction, or the inability to lengthen your muscles to their full capacity or produce force in a desired position, throughout your body. 

For example, if you’ve ever twisted an ankle, you’ve seen firsthand how a symmetry imbalance can wreak havoc on your body. Your left and right ankle muscles will start to function in very different ways. This creates a chain reaction in your knees, hips, spine, shoulders, and neck. It’s called a limp. If you end up on crutches, your entire method of locomotion changes dramatically.

If you’re lucky, your ankle’s functional abilities return to normal and you nix any remaining trace of the limp. If you’re the average Joe or Jane, though, you maintain that asymmetry indefinitely. To start with, you had no idea what your ankle’s FULL functional abilities were before your injury, so you never fully rehabilitate, and you end up with long-term issues. You could have prevented this chain reaction if you knew the full range of motion of your ankle to begin with.

You make do with whatever your never-completely-healed ankle can do. You may have a small or large trace of the limp. Over time, you notice extra soreness in your low back. And after another 5 to 10 months (or years), you end up with a bum shoulder or a crick that only happens on one side of your neck. Your doctor or physical therapist says, “Meh, that’s just how it is as you get older.” 

The end result of symmetry imbalances is body-wide adaptation. You want to identify and address symmetry muscle imbalances before they become larger problems. 

The more pronounced the asymmetry and the longer it's allowed to linger, the higher the probability of accruing problems, including pain, or a loss of strength or range of motion.

With both symmetry muscle imbalances and joint muscle imbalances, you’re likely to limit your ability to perform basic movements. You may feel afraid to bend over to pick up grocery bags, or feel reluctant to lift your child. You feel older than your years.

When pushed too far and for too long, imbalances result in acute and chronic pain. They make something as simple as sleeping feel problematic. 

We can't always predict the consequences of specific muscle imbalances, but we can say that there are physical consequences to physical choices.

Finding muscle imbalances helps you become someone who can move right and feel right, or achieve any motion you want or need without pain, discomfort, or instability.

A meme of a sloth bear about taking naps.


Why the Impacts of Muscle Imbalance are Difficult to Study

Doctors, physiotherapists, chiropractors, and trainers may claim that symmetry doesn't matter. I have seen intelligent writers that I respect make this claim. 

To be fair, there are no prospective double-blind, placebo-controlled studies  that correlate muscle asymmetry  to an experience of pain or discomfort. There are no studies showing that if your left quadriceps group is 40 percent weaker than your right at creating knee extension, you'll experience back pain, or that if your thoracic spine has significant curvature, you'll have shoulder pain.

Attempts to show correlation between muscle imbalances and specific symptoms will forever fail. Why? Because individual variations will confound the results. Pain tolerance varies by individual. Proprioception varies by individual. Ideal muscle resting length varies by individual. Ideal muscle strength (of the muscles in question and the ones surrounding it) varies by individual. Compensation patterns vary by individual. 

All these things that vary by individual also vary by context. For example, according to the International Association for the Study of Pain, your pain tolerance is affected by your mood, your relationships, your job, your stress levels, and more.

See also: How Shifting Your Perspective on Chronic Pain Can Help You Heal

The strength of your left quads are guaranteed to be different from mine, which is guaranteed to be different from my friend's. The way you get in and out of a car is different from how a gymnast might get in and out of a car. Your car is probably a different height than mine. How long you spend in a car is different from how long I spend in a car. Two runners will have different strides. Two bikers will have different limb and seat geometries. The list of potential confounding factors is endless. 

It’s impossible to quantify and adjust for all these confounding factors. At best, researchers can try to ignore them and claim that a large enough sample population would negate their effects. That might work for a drug trial, but it makes no sense to ignore the condition of an individual body's movement system when you're studying the body's movement system. 

It's like saying you can research the effects of watering various gardens every day, while ignoring the types of plants in the gardens, the condition of the soil, the amount of direct sun the gardens get, and the overall climate the various gardens are in. You'd have a bunch of flawed data that would lead you to conclusions that would kill a lot of plants. 

Ultimately, the question of symmetry muscle imbalances is one of physics. Our bodies have mass. If I position or move my mass symmetrically, it requires muscles all over my body to work in a specific way. If I position or move my mass asymmetrically, it requires muscles all over my body to work in a specific and different way. 

We know that muscles can signal fatigue when worked to exhaustion. We know that muscles can signal stiffness or tightness. Asymmetrical work will cause some muscles to signal sooner than others. This is all normal muscle function. 

If I walked around with a phone held to my head with my left hand, you would expect my left arm and shoulder muscles to develop aches and pains. My right side? Not so much. It's just hanging out. But if I maintained this pattern for years, it’s plausible that the strength of the left side of my neck might deteriorate and that the right side of my neck and my right shoulder might show some effects from having to do all the work my left doesn't as I go about my day.? 

I'm not against science at all, but I am against scientism that blinds us to the obvious and absolves us of responsibility for our own actions. We don't need double-blind, placebo-control tests to verify that if I let go of an iPhone, it will fall to the floor. These are simple observations of cause and effect in our physical world.

A Note for Skeptics 

If you have chronic joint and muscle pain and you're skeptical it could be related to muscle imbalance, I have simple advice (this is also assuming you've ruled out extremely low probability causes like cancer).

Pretend that muscle imbalances are causing your issues. Train your muscles to correct the obvious asymmetries despite your skepticism. If you fix your asymmetries and dysfunctions and you still have pain and discomfort, then what have you lost? 

You haven't wasted time. You've made your body stronger, and you will have learned something new. 

In the vast majority of cases, you will  have learned that muscle imbalances were causing your issues.



How to Identify Muscle Imbalances

When looking at a human body, you can spot clear signs of imbalance and asymmetry. There are two steps to assess muscle imbalance. Neither is high tech nor requires special training or devices that cost thousands of dollars. In short, muscle balance assessment is cheap and easy.

Step 1 for Identifying Muscle Imbalance: Visual Assessment

A visual assessment gives you  information quickly.

For example, you can easily see when someone has no butt muscles (or flat, sagging, deflated butt muscles). Muscles without volume are muscles that don't get used.

Deflated butt muscles

Muscles without volume are muscles that don’t get used.


You can see people with their shoulders stuck in a forward slump. This tells you about muscle function. Muscles on the front of the chest are in a generally shortened state and the muscles in the back near the shoulder blades are in a lengthened and (likely) weak state.

Looking at the spinal erectors, you might see one side sticking out and the other invisible. That would be a clear sign that one side activates more often than the other.

See also: Torso Rotation Assessment for the Back Pain Fix

A shirtless man hunched over to demonstrate unbalanced spinal extensor muscles.

You can usually see uneven spinal extensor muscles.


 Looking at neck muscles, you might spot one side that’s more developed than the other.

The back of a neck, showing muscle imbalance.Obvious neck muscle imbalance.


Step 2 for Identifying Muscle Imbalance: Functional Assessment

To get detailed information that verifies a muscle imbalance, we use functional tests. 

This is a fancy way of saying “try exercises or movements.” 

As you encounter difficult movements, you learn about the state of muscles throughout your body.

For example, if you can do 50 pushups, but you can’t do a row without fatiguing,your pushing muscles are in a lot better shape than your pulling ones.

If you can lift your right leg up in front of you, but you can’t do a single leg bridge on that leg to save your life, your hip flexors are stronger than your hip extensors.

If you can’t tilt your head to the right but you can to the left, that could be a sign of a symmetry muscle imbalance in the muscles on either side of your neck. 

See also: The Secret History of Joint Pain


Muscle Dysfunction vs. Muscle Imbalance

Finding muscle imbalances is important, but it is just the first step in the search for dysfunctional muscles.

A dysfunctional muscle is one that: 

  • cannot lengthen or shorten enough to allow smooth joint mechanics 
  • does not have the strength to control the bones it is attached to

A muscle is functioning to its full potential when it's able to produce adequate force to create pain-free movement into and away from its fully lengthened and fully shortened states, as well as into and away from intermediate lengths along the way.  

Put more simply, a functional muscle has strength at every length. 

For example, let’s say you do a quick comparison between the hip flexion strength and range of motion on your right side versus your left. Your right side comes up to about 60 degrees of flexion. The left side comes up to only 50 degrees of hip flexion.

Matt Hsu demonstrates 60 degrees of hip flexion on his right leg. TE: make sure image title and description fields are populated, too.

Less-than-optimal hip flexion.


You also discover that you can keep your right leg up for 30 seconds at that height without issue. On the left, you can only stay at 50 degrees for 5 seconds before the thigh starts burning.

You can start addressing that imbalance ASAP. But you should keep in mind that what you’ve really discovered is BOTH SIDES are dysfunctional.

Cue horror soundtrack.

Meme of Luke Skywalker crying.


In this example, your hip flexion range of motion is limited on both sides. The left side is worse than the right side, but neither side is that good. At a bare minimum, you should be able to flex your hip 120 degrees for healthy hip range of motion. You’ll need more range of motion if you are practicing squats. Not only are your muscles imbalanced from side to side, but they’re also dysfunctional on both sides. Fixing the symmetry muscle balance won't be a complete fix. 

The problem is that you can't lift the weight of your own leg through a pretty minimal range of motion. You couldn't lift your own knee to your own chest if your life depended on it.

And in some ways, your life does depend on it. What if you needed to step up onto a high rock or ledge to get over a big gap? What if you just want to step over your nephew's skateboard on the garage floor without breaking your neck (or the board)? Or, worst case, what if you needed to step over a large log to get away from a pack of hungry hyenas? 

Modern living presents few true in-the-moment life and death situations, so we can get away with dysfunctional muscles for a long time. But life is a lot better when your muscles function well. Your options increase and your ability to deal with challenging situations improves. This, in turn, leads to more confidence, less pain, and a better mood. 

Your body is a lot more comfortable when muscles get adequately challenged on a regular basis, and are capable of taking on new challenges! 

To be able to handle varied challenges, you need functional muscles.

See also: Fixing Chronic Pain Flare-Ups when fixing dysfunctional muscles


Where do Muscle Imbalances and Dysfunctional Muscles Come From?

People often have an idea of their bodies as perfectly self-regulating. There's certainly some element of truth to this. Our bodies are incredibly complex and do an excellent job of maintaining function throughout our lives, even when we're making bad choices.

That said, there are always limits to what your body can handle. You could probably get away with eating nothing but butter for a few months or years, but eventually your digestive and cardiovascular systems are going to want to have a chat.

An illustration of a gingerbread man eating butter until he falls over.

Your muscles are incredible at adapting to the demands placed on them. As long as you don't massively exceed your muscles' abilities, your muscles gradually adapt. 

Similarly, if you never lengthen a muscle, it will no longer be able to lengthen without a lot of effort. If you never contract a muscle, it will be unable to contract with much force, if at all. 

When our lives put us in positions where some muscles are squished and choked off from any blood supply, those muscles atrophy. 

It’s not surprising that people who sit all day often have no butt muscles.



With many of us spending our waking hours sitting in chairs and participating in repetitive recreational activities, it's easy to see where dysfunction and imbalance arise. 

A golfer always swinging to her left trains her body into massive symmetry imbalances. A desk worker who slouches while typing all day will find it difficult to un-slouch. Her spinal extensors become dysfunctional. A long-haul truck driver will find it hard to stand up, walk, run, jump and move his arms and shoulders through a full range of confident motion. Muscles all over his body become dysfunctional from disuse and chronic, repetitive positioning. 

And, to be clear, someone standing in a false idea of "perfect” posture all day long won't be better off. Being stiff and stuck in a straight position can be just as dysfunctional as being stuck in a slouch. If you can't flex your spine or touch your toes because you've been locked in perfect posture all day, you've still got problems.


The Queen’s Guard.

"Guys, can any of you touch your toes?"

The more you ask your muscles to specialize in specific motions or positions, the worse they get at handling the variety of basic movements necessary to feel confident in your body.


How to Identify Muscle Dysfunction

The process for identifying a dysfunctional muscle (or muscle group) is the same as for muscle imbalances. We use low-tech tools that humans have always had easily at hand, including visual assessment and functional tests

Let’s look at an example of how we could do this with someone’s hip flexors.

Step 1 for Identifying  Muscle Dysfunction: Visual Assessment

For visual assessment, you can look at a person and tell whether they are actually stuck in a bit of hip flexion. This presents as anterior pelvic tilt with extension of the spine. Their thigh muscles are not very well developed. This visual assessment tells us that the muscles of the anterior hip are resting in a shortened state and are likely to be weak, or dysfunctional.

An anatomical illustration of shortened hip flexor muscles.

Can you tell the muscles of the anterior hip are shortened?


We might also notice that the thigh appears to be bony. There's no meat! There’s NO size to those muscles. Muscle strength is not always directly related to size, but if you notice that a muscle is so atrophied that it’s not there, you can safely conclude that the muscle isn’t strong. It's not getting used enough to maintain a decent size.

A meme of a model on the runway, with no muscle definition.

A lack of muscle can cause joint pain. Original photo by Christopher Macsurak


Step 2 to Identifying Dysfunctional Muscles: Functional Test

For the functional test, the person does something simple, like lifting a leg straight up in front of him (sagittal plane for nerds), or bending a knee. See how long this person can hold the position.

If fatigue and cramping start in less than 30 seconds (and it usually does), you’ve got yourself some weak hip flexors. Most people can’t do this for even five seconds without fatigue or cramping. Sometimes it's in muscles other than the hip flexors. (This would tell you that the body is using muscles other than the hip flexors, and those muscles don’t like it.)

Can-can / Standing hip flexion from Upright Health on Vimeo.


You can also test for dysfunction in a position that tests the hip flexors in a lengthened position.

From a wide stance, see how far someone can fold forward with slightly bent knees and a flat lower spine and posterior pelvic tilt. See if they can use the hip flexors and quads to bring them back up to the start position.


Split squat tucked from the FAI Fix

If they can barely lower themselves down or it causes them intense discomfort to even try, we know the muscles on the front of the thigh are dysfunctional. They are unable to lengthen.The same is true of getting partially down with discomfort.

If they can get all the way down and back up without issue, then the hip flexors and quads are doing well in that lengthened position. (*note: this basically never happens for the average deconditioned person).

A Common Muscle Dysfunction 

Modern humans who sit in their cars, on their couches, and in their office chairs often have chronically shortened and weak hamstrings.

In any given individual, we can see this by observing:

  1. Lack of size in the back of the thighs. If the thighs look like a thigh bone, the muscles of the thighs are missing. When an adult participates in an activity that has created well-developed hamstring muscles, the next observations are then crucial.

  2. An inability to bend at the hip joints and touch the floor. For the majority of adults, this results in the knees bending, the spine flexing, or sections of the hamstrings crying out in agony. Even with these compensations, many adults still cannot touch the floor comfortably.

    Matt Hsu demonstrates a forward fold and touching the floor with straight legs                                     Can you touch the floor with straight legs?

  3. An inability to lift moderately heavy objects off the floor (25 percent of your own body weight) while maintaining a straight spine and straight knees.

  4. An inability to bend the knee and pull the heel up toward the butt using the hamstrings (and no hands!) for 30 seconds without massive (and alarming) cramping.

Matt Hsu demonstrates quadriceps-hamstring balance.

See how close you can get your heel to your butt.


If you did the tests above and failed, don’t feel bad. The overwhelming majority of modern white-collar workers will fail at least one (if not all). Blue-collar workers whose jobs actually put them into a variety of physical positions might do better, but even they are often grooved into very limited daily movement patterns. Dysfunctional hamstrings are very common. Based on my own observations, I’d say 85 percent of all male bodies between the ages of 18-99 have dysfunctional hamstrings. 

I don’t think it’s that much different for female bodies either. For a lot of women, the ability to lengthen the hamstrings is not the problem, rather the hamstrings are weak when lengthened.

I know you'll be tempted to rationalize that the tests must therefore be unreasonably difficult. After all, if so many "normal" people fail, surely the tests and my expectations must be broken. I'll cover that later.

In the meantime, remember this: You need to have strength at every length.


Apply Functional Tests to Your own Dysfunctional Muscles

When you fail a functional test, you know you have a problem to address. To put a more positive spin on it, you have a new skill to add to your repertoire.

You've identified something you aren't good at, and you're about to dedicate yourself to make it better.

Here are more functional tests you can do on your own. Start simple with things like waking up the stairs or picking up something from the floor. Then get more complex as you keep looking to improve your range of motion and strength. :

Basic Tests:

  • Can you touch your toes?
  • Can you reach your arms straight overhead?
  • Can you squeeze your butt muscles?
  • Can you put your foot up on the kitchen counter?
  • Can you get one leg up over the top tube of your bike? Can you do it with the other leg too?

More Complex Tests:

  • Can you do the front splits? 
  • Can you do the side splits?
  • Can you do a chin up? 

The number of options is limitless. For advanced human movers like gymnasts, the functional tests can get far more involved and granular (although simple tests can be just as important for them).

If you're interested in testing your own body, you should choose simple movements that you fully grasp. You should know what primary muscles need to work to execute with proper form.

Don’t choose a complex, compound, or high-level movement to test an isolated muscle group. For example, you wouldn't choose a clean and jerk to test your glute strength. There are too many joints moving at the same time. That means a lot of muscles are working at different points in the movement. There's too much extra noise.

Instead, you would pick something simple that clearly uses only the glutes within their full range (or enough of a specific range you're investigating) and without a whole lot of extra noise, such as a glute bridge. The glute bridge is an easy, low-level exercise. Over time you could increase the challenge to a weighted bridge, a single leg bridge, or a hip thrust. The point is that you start easy and progress to harder tests. 

Remember to test muscles in both lengthened and shortened states. Especially around the hips, people have lots of shortened muscles. While it’s important to ensure muscles are strong in shortened positions, it’s equally, if not more important,  to strengthen them in lengthened positions. 

If you continuously strengthen muscles in shortened states, those muscles will end up weaker than you wish, and they will also start to impair range of motion at the joints they cross. It's also a fast track to extreme soreness and achiness in the muscle and around the joint.

A meme of Matt Hsu checking out his biceps and making duck lips.

If you just train bicep curls all day, you'll experience trouble straightening your elbows and moving your shoulder joint through a full range.


Muscles that are unable to lengthen will lead to poor joint range of motion and pain and discomfort. 

Again, you need to have strength at every length. 

See also: Can miserable malalignment be fixed quickly?



What is Normal Muscle Function?

You might be thinking, “but I don’t know the metrics for what’s good enough for any given muscle!” 

There’s no need to search for double-blind, placebo-controlled studies on what “perfect” or “normal” is for any given muscle group.  

Any movement you see another human perform is one that you can also perform given enough time and training. (I talk about it in this podcast interview with GMB). Any movement you cannot currently do is one you can improve on.

The goal is to feel good in your body and challenge yourself incrementally to feel even better. 

If you see another human perform a movement that you want to be able to do, start from this assumption: I can do that if I train my muscles to do it. And follow it with this question: What muscles do I need to focus on to do that?” 

It does not matter how incredible the movement is. It does not matter how far out of reach it seems. It doesn't even matter if you won't even be alive long enough to train your body to do that movement. Just start investigating HOW you would get there. 

If you see someone doing a complex motion, think about how to break it down into simpler steps.

For example, if you want to do a cartwheel, you don't have to jump right into it and hurt yourself!


You can check on some of the preliminary steps.

  • Can you put your arms up next to your head? If not, start there!
  • Can your hands and wrists bear your weight? If not, start there! 
  • Can you side bend without feeling like your ribs and belly will tear apart? If not, start there! 
  • Can you balance even momentarily on one leg? If not, start there! 

No matter how complex a movement looks, there are component pieces you can improve on to get closer to achieving that motion. 

It's easy to rationalize away your muscle dysfunctions by saying, "this is normal because I see it in everyone else." It's easy to start looking for solace in the research literature.

But before you get lost in PubMed searching for peer-reviewed literature on “normal” muscle function, let me save you some time. I want you to make progress instead of wallowing in an echo chamber of futility and feebleness.


Let Me Introduce You to the Physically Feeble Fallacy.

The Physically Feeble Fallacy is simple. When we are physically feeble, we tend to rationalize and normalize it. We come up with reasons that we should allow this to continue. Sometimes we tell others that "in time, you'll be like me too."  

This is a natural tendency in all of us. We tend to see our own functional abilities as "normal." It is what we see the most on a daily basis, after all.

You've probably heard your mom, dad, and doctor say, "Yeah, going up stairs (or down stairs) is just something you can't do as you get older..." Or "yeah, my knees just don't hold up to running. No surprise, though, since humans aren't made to run!" 

It can cut in the opposite direction too. 

I once went to a handstand workshop with a talented acrobatic teacher. She had been an exceptional athlete for decades. My friend was curious about the challenges of doing one-arm handstands at the time. One-arm handstands are not easy for the average human being. It takes dedication to develop the skill. The teacher, of course, had mastered the skill years ago and still maintained the skill with ease. 

Paraphrasing the conversation... 

Teacher: "Can you stand on two feet?" 

My friend: "Yes." 

Teacher: "Can you stand on one foot?" 

My friend: "Yes." 

Teacher: "Same thing. It's not that hard." 

The teacher normalized her own abilities and didn't see (or remember) the challenges she had faced (or maybe it came quite easily to her!). 

Knowing that the physically gifted and the physically feeble normalize their own abilities, using medical literature to determine what is “normal” or “acceptable” for any given muscle group or movement is a terrible idea. 

The people who research “normal” are inherently biased to see their own crappy function as normal. They then conflate “uncommon” with “abnormal.” They fall victim to the Physically Feeble Fallacy. 

Put another way, if I have crappy movement abilities, I'm likely to see that as the baseline. I'm highly biased to set the standard for "normal" somewhere around what I can achieve. Put me in a room with other researchers who also have crappy movement abilities, and the result is predictable. Crappy movement looks more and more "normal" because of what's "common" around us.

This is why you hear a never-ending cacophony from health professionals that sounds like this: 

  • Don't ever put your arms overhead because it's bad for your shoulders.
  • Don't look up because it's bad for your neck.
  • Don't bend at the hips because you'll hurt your back.
  • Don't lift with your back.
  • Don't stretch because flexibility is purely genetic. 
  • Don't run because it's bad for your knees. 
  • Don't jump because your body isn't designed to handle it.
  • Don't walk too far or your feet will hurt.
  • Don't let your bare feet touch the ground or your feet will hurt.

All of these warnings and statements arise from good intentions from people who are themselves physically feeble and dysfunctional.

The doctor who cannot reach overhead, look up, or bend at the hips with a strong, neutral spine will not give you good advice about those movements. He cannot understand how vital these movements are to a full and healthy life because he doesn't have these basic skills. He will rationalize those movements away as being "unnecessary."

The health professional who has never taken the time to learn how to stretch properly, run properly, and jump properly will never understand the real demands and real effects of these activities. She will say "that's too dangerous for the human body." 

The person who hasn't walked barefoot on any surface for the last 30 years has no understanding of full foot function

Medical research on human movement and joint pain is based on wildly outdated models of the human body. The researchers themselves rely on those models to justify their own poor physical movement abilities. As movement problems become more common, their papers paint feeble as "normal." 

Do not fall for the Physically Feeble Fallacy!


An Experiment on "Normal" Movement?

Take a group of 100 people and strap them into chairs for 3 months. Never let them get up. At the end of 3 months, 85 percent of them will be unable to stand up without assistance. In this group of humans, the inability to stand from a chair is now “normal.”


Matt Hsu demonstrates standing up from a seated position.

Notice how your hips and knees move and feel when you stand up after sitting down.


But it’s not “normal” for a human to be unable to rise from a seated position.

In research on “normal” movement in humans, you will find that physical therapists and medical doctors miss the context in which their human subjects live. Humans sitting in seats 85 percent of their day should not be examples of “normal function.” Humans who do not regularly move in a variety of ways under varying levels of intensity will not develop or maintain “normal function.” You will simply see feeble capabilities more commonly.


Aim for “Uncommon” Muscle Function

You may see a gymnast’s or martial artist’s abilities as abnormal, but what you’re actually seeing is someone with strength and mobility that is uncommon. That level of function is normal and achievable. It just takes time and practice. 

You may think what separates you from these uncommon people is genetics, age, or some other factor that is out of your control. The uncomfortable truth is that’s not true. It's a nice excuse that absolves you of personal responsibility.

A small gray, long-haired dog sleeping.


What separates people with uncommonly good movement abilities is the amount they have practiced. It’s the amount of time they’ve spent asking their bodies to move in ways that the average office worker hasn’t. 

Genetics can amplify the effects of practice, but zero guitarists became great by playing video games or studying the stock market all day. Ultimately, practice and repetition are what create competence and confidence.


The Role of Bones in Muscle Dysfunction and Imbalance

Orthopedic doctors have a tendency to blame bad bone shapes and bone decay, including arthritis, for movement problems such as shoulder impingement symptoms, hip pain, back pain, and knee pain.

Whenever researchers bother to check these theories, they discover something shocking. 

The bone shapes have no correlation to range of motion or pain. 

Unless bones are shattered or formed in a way that is a significantly large deviation from normal (like scoliosis), bone shapes have a very limited influence on the available range of motions.

Even with orthopedic “pathologies” like arthritis, joints that are allegedly misshapen by a few millimeters, and alleged damage to soft structures in the joint have been shown to be irrelevant to ranges of motion and pain. (Read more on pain here or Surgery: The Ultimate Placebo, by Ian Harris, an orthopedic surgeon.)

The level of bone "damage" has no correlation either. Not for shoulder impingement, hip impingement, knee arthritis, or back arthritis.


What About Manual Muscle Testing? 

In medical and physical therapy literature, you may come across something called manual muscle testing, when a doctor or therapist puts you in a position and asks you to fire muscles against light resistance. Some medical professionals use this as an objective and evidence-based method for rooting out muscle dysfunction. 

But strength in a muscle is length- and position-specific. So manual muscle tests aren’t reliable.

Here’s an example: You have Athlete A who can deadlift 200 pounds with straight knees. His hamstrings (and back) are clearly strong for that movement.

Matt Hsu demonstrates a deadlift.Dramatization. Not actually 200 pounds in this image. 😂


You have Athlete B who weighs 200 pounds and can do the front splits. He holds his body’s weight using his hamstrings on the front leg and the thigh and hip flexors on the back leg. His hamstrings are clearly strong for that movement. 

Shane Dowd of does the front splits outside.

This is my friend Shane. He doesn't weigh 200 pounds. But he can teach you how to do the Front Splits in 45 Days (affiliate link to his program)

Athlete B cannot necessarily do what Athlete A can do, and vice versa. 

They each have built very strong hamstrings for a specific activity. There may be some small amount of carryover between these movements, but true strength and mastery of any given movement requires practice of that specific movement. 

If Athlete A also trains to do the front splits, he'll be able to do the front splits. If Athlete B also trains to do a straight-legged deadlift, he'll also be able to do that. 

And if you ask these two athletes to do an entirely different hamstring exercise that tests the hamstrings' ability to bend the knee, you'll discover almost no carryover! 

It would be the same if I do a bunch of bicep curls in a standing position, then try to do bicep work while on my back. Muscle strength is dependent on length and position. You can’t train muscles in one orientation and expect to have good development and function in all of the lengths and angles you haven't trained.

With traditional manual muscle testing for hamstrings, for example,  you lie face down and  lift your foot and leg toward the ceiling. Some textbooks will say something to the effect of, “if they can do it, their hamstrings are okay. Dysfunction is elsewhere.” 

But the muscle test only tested that one angle for that small degree of motion and with only the weight of the leg itself and some slight resistance from the tester. 

Being able to lift the leg itself may be a challenge for the average modern human who sits all the time; however, it’s a totally arbitrary and unambitious minimum expression of strength. Since all our minimum standards are arbitrary, why should we use one that barely translates into even moderately functional locomotion? 

Manual muscle testing has the veneer of objectivity because it is somewhat objective. You can or cannot perform the requested motion. Simple and objective. However, the minimum performance to achieve “good enough” is set so low as to be pointless. And the belief that “good enough” applies to all the angles and lengths that muscle can adopt is demonstrably false.

 Meme of a penguin saying “it’s objective, therefore it’s right.”



What’s the Point of Finding Dysfunctional Muscles and Muscle Imbalances?

 The point of finding dysfunctional muscles and muscle imbalances is not to get obsessive over how broken your body is. The point is to see clearly where you can improve your body’s capacity to work and play.

The goal of finding dysfunctional muscles is to expand your body's capabilities into multiple realms.

matt hsu skateboarding

Rooting out dysfunctional muscles makes all kinds of activities (however random) possible. I decided to try a longboard skateboard at the age of 39.


This is where the conventional medical approach goes awry. Medical professionals are trained to see failure in functional tests as a sign of congenital deformity or irreversible structural damage. They are trained this way despite an endlessly growing body of history and research literature that disproves these interpretations. 

If you’re someone with chronic pain or someone who’s interested in optimizing your body’s movement capacity, muscle function matters. Assessing your abilities in an honest way gives you a constant line of fresh challenges. If you look at each dysfunction or imbalance as a new skill to acquire, you’ll find yourself on a journey that is physically challenging, comforting, and rewarding all at once.

Finding joint muscle imbalances helps you improve movement at a specific joint. 

Finding symmetry muscle imbalances helps you improve movement of the entire body. 

And finding dysfunctional muscles helps you improve your movement capabilities at the most fundamental level.

To be clear, there are no quick fixes. It's a learning process. As you test yourself, you'll learn things about your body and your life. As you add to your movement repertoire, you become a human who moves right and feels right. As you move right and feel right, your confidence will grow.



Ready to fix your own muscle imbalances? Learn how to fix dysfunctional muscles and muscle imbalances in this article:  “How do you fix Dysfunctional muscles and Muscle Imbalances?” 

Or want to learn more about how massage affects chronically "tight" muscles? ReadWhy Massage Sometimes Makes Your Body Feel Worse.”

Train your body to be more flexible, strong, and resilient! 

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