What is A Muscle Imbalance (& How to Know if You Have One)

As much as you might try to avoid it, the chances are you’ll develop some sort of muscle imbalance over the years. I’m not talking small differences that come from your dominant side being stronger than your non-dominant side.

A noticeable muscle imbalance can throw off your aesthetics and mess with your proportions. It can impact the way you lift weights, perform movements and change the way you look.

What Is a Muscle Imbalance?

Simply put a muscle imbalance is a difference in either size or strength between 2 muscles or muscle groups and can be categorised in 3 ways:

  • A symmetrical imbalance could be the difference in the size of your biceps, pecs or thighs. This would give one side the appearance of being bigger or more developed than the other.

  • A strength imbalance could be the difference between one leg and the other or one shoulder and the other, causing the barbell to rise faster on one side when doing a squat or shoulder press.

  • A proportional imbalance could be the difference between your chest and back or your upper body and lower body. This would impact your aesthetics by making your upper body look too big for your lower body or your back is small and weak compared to your chest.

What Causes A Muscle Imbalance?

Some people say you only get imbalances if you follow a poorly planned training programme but, you can develop imbalances even if you’re following the perfect routine.

The common causes of muscle imbalances are:

  • Poor programming

  • Bad technique

  • Injury

  • Mobility or flexibility issues


Poor Programming

There are a number of situations that can cause muscle imbalances but unsurprisingly the most common one is poor programming.

Problems usually arise when you only focusing on the muscles you can see, i.e. the ‘mirror muscles’, hello chest, shoulders and biceps aka the ones you enjoy training.

When you do this, you neglect the other muscle groups that contribute to a rounded physique.

This means that you end up building a mismatched and out of proportion physique, which can lead to;

  • A mismatched upper and lower body

  • Underdeveloped and weak muscles

  • Bad posture

  • Poor lifting technique

  • An unattractive physique

Not a good look.


Bad Technique

Another cause of imbalances is bad technique and a general lack of focus when lifting. The usual culprits are;

  • Daydreaming

  • Browsing on your phone

  • Chatting

Your aim in the gym should be to give 100% and train with intensity. This means remaining focused and aware of your technique.

When training you should be;

  • Visualising your next set

  • Focusing on your technique

  • Listening to motivating music

  • Staying in the zone

This is because a lack of focus can lead to bad technique, which will ultimately result in unnatural lifting patterns where one side of the body ends up doing more work than the other.

Before you know it one side of your chest is bigger and stronger than the other and you’re left wondering how you got there.



Another common cause of muscle imbalances is injury and unfortunately, there’s not a whole lot you can do about it. For example, if you break your leg or arm, chances are that the injured side will naturally become weaker and smaller than the healthy side.

If this is the case, then your focus should be fixing the imbalance once you’re injury free.


Mobility or Flexibility Issues

This one ties into most of the others causes and can be the fundamental reason for bad lifting technique and even injury.

It’s often the root cause of muscle imbalances and if you’re still at the stage where you haven’t developed any big imbalances then it’s worth revisiting your technique and working on your mobility and flexibility to help prevent any imbalances from forming.

Additionally, ensuring you warm up properly and stretch after your workouts will go a long way to improving your mobility and technique.

How Do You Know If You Have a Muscle Imbalance?

The majority of the time muscle imbalances are quite obvious. However, because they develop slowly over time you might not notice until it’s very noticeable.

Below are 5 ways to monitor and check for muscle imbalances.


Monitor Your Strength

Not just how much you can lift but the way you lift it.

Pay attention to the way your body moves, is one side of the barbell rising faster than the other, can one arm do more reps than the other, are you twisting and rotating when you shouldn’t be?

All of these things are signs of a strength imbalance.

Now look at your training notes (you’re keep training notes, right?!);

  • Are your triceps much stronger than your biceps?

  • Is your back weak compared to your chest?

  • Is your upper body stronger than your lower?

Depending on the lift you’re doing you can use a mirror to check otherwise film yourself or get someone else to.


Look At Yourself

Probably one of the easiest ways to identify symmetrical imbalances is to study yourself.

For example;

  • Does one bicep look bigger than the other?

  • Is more pec more developed than the other?

  • Are your legs the same size or is one lagging behind?

The best way to do this is to take photos monthly and compare them to see how your body is changing.

You can also use this method to check your proportions, it can be easy to hide a difference between your upper and lower body behind straight legged or relaxed fit trousers but standing in front of your mirror in your underwear gives you nowhere to hide.


Take Regular Measurements

This goes hand in hand with the point above and will help confirm any suspicions you have about symmetrical imbalances.

Take main body measurements;

  • Biceps flexed

  • Arms relaxed

  • Chest

  • Shoulders

  • Thighs

  • Waist

Do this once a month and track how things change.


Notice How Your Clothes Fit

This is a great indicator of changes in the body and sometimes the surest sign of muscle growth or fat loss in the body.

Be aware of how your clothes fit;

  • Is one trouser leg tighter around the thigh or calf?

  • Does one t-shirt sleeve fit tighter than the other?

  • Does your chest look well developed but your back looks underdeveloped?

All the above can be signs of a muscle imbalance and a great anecdotal indicator that something might be going wrong.

You can then use the other methods listed here to confirm your suspicions.


Analyse Your Posture

Posture can be a great indicator of muscle imbalances as well as mobility and flexibility issues.

For example;

  • Are your shoulders rounded forwards?

  • Is pelvis anteriorly tilted?

  • Can you touch your toes with straight legs?

All these things are signs of tight, weak and/or underdeveloped muscles that point to a potential muscle imbalance or a problem that might cause one further down the line.

Takeaway Point

Avoiding a muscle imbalance is as much about knowing what causes it as it is knowing how to identify them.

Knowing how to do both these things will allow you to put systems in place to avoid getting a muscle imbalance, whilst having the knowledge to track whether any muscle imbalances are developing.

You can then set about correcting these imbalances if you need to.

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