Muscle Confusion – Everything You Need to Know About it

As fitness is becoming a more and more prominent part of our lives and society as a whole, it’s no wonder that the average Joe is starting to learn about different concepts on his own, trying to extrapolate myriad of workout routines guaranteeing better results.the science of muscle confusion

And while almost everywhere you are trying to look for a bigger gain in knowledge will lead you to one study or another, the term of “muscle confusion” will leave you guessing and quite frankly confused (no pun intended).

You can literally search to your heart’s content and still end up faced against the catchy one liner that your average fitness layman would provide. Either that, or listen to the media who share statistician’s level of fascination with charts, still not explaining a damn thing (The P90X commercial does really come to mind).

What is muscle confusion? – The genesis of the phrase

For some it’s a complete fallacy, for others a deciding factor in either purchasing or creating a workout program on their own. The truth though is far from unilateral. You see, providing an intelligible response is not easy simply because studies on people are notoriously hard to construct. Hence all really stems to vague rhetoric that has been parroted around, that people decide to repeat and believe “simply because”.

The term stands for a training principle that states that muscles accommodate to a specific type of stress when the same stress is continually applied to the muscles over time; then one must constantly vary exercises, sets, reps and weight to avoid accommodation (homeostasis, or plateaus if you so prefer). This results with lack of boredom, improved functionality of the muscles, and most importantly bigger muscle gains and improved weight loss.

It is also said that muscle confusion works best for general physical preparedness programs, or for breaking out of plateaus during conventional periodization programs. When it comes to strength and specific type of performance, “confusing the muscles” is not that smart of a choice since it suggests less than optimal performance. More on that later…

So does muscle confusion work?

does muscle confusion work?We have to be more specific here. Does it work for what? Weight loss, hypertrophy of the muscle, increased performance… We are not discussing a general law here, but rather a concept, so it has to be taken in one context or another.

In a way it all boils down to the context under which you’ve heard it. And as such it can stand for couple of explanations.

You’ve probably heard this phrase due to overly marketed workout programs such as P90X and fitness aficionados trying to share some science in layman terms. Anyway, let us delve into the semantics.

The term confusion

When you think about it “Confusion” is sort of a muscular anthropomorphism, just semantics. And people are increasingly eager to get caught up in the semantics it seems. Before you know it you are getting arguments of the kind that muscle confusion cannot be accurate since there is no way that you can “confuse” a muscle or “keep the muscles guessing”. The conversation henceforth always takes a form of a caricature. But I digress…

If from a semantic point of view you decide not to distinguish “confusion” from the already used term “periodization”, then muscle confusion as a whole changes its meaning.

That’s what I meant when I said that it can be interpreted in various ways, you see.

The different meaning behind it – couple of concepts using the phrase muscle confusion

As you try to figure this out on your own you will be faced with a noticeable lack of scientific arguments that either support or disregard the concept. You will find, here and there, different words that provide some context, but other than that it seems like this is something that has been taken off right out of a hat- no background at all.

The methods supporting and describing it however CAN be analyzed on a higher ground.

Muscle confusion in the context of muscle periodization

Like I said earlier, if muscle confusion is mentioned in the context of muscle periodization (see the excerpt bellow),

Periodization is the process of structuring training into phases. During different times of the year, training programs vary in the length or number of repetitions in a training session (volume) and the percentage of one’s maximum capacity (Intensity). The purpose of Periodization is to cause the muscle to continually adapt to new conditions of overload and to allow the muscles to recover from the stress of training.

It is entirely legit in the sense that periodization is proven, on a scientific basis, to generate results. In muscle hypertrophy (muscle gain), muscle strength, muscle endurance…

Muscle confusion by introducing compound exercises and reciprocal supersets

Muscle Confusion By Introducing Compound ExercisesIf muscle confusion is however used in the context of changing exercises as to provide more of a muscle growth and weight loss, that’s another story begging for different scientific explanation.

The context in which commercials (such is the one for P90X) use it, is usually this one.

It states that by changing the exercises or the nature of the exercises (strength, balance, flexibility, cardio…) you are applying more of a muscle stress, hence causing more hypertrophy, and ultimately causing more weight loss. The weight loss aspect in the equation is due mostly to the fact that muscle confusion suggests compound exercises with the activation of agonist-antagonist muscle groups.

This type of training is called reciprocal supersets. Reciprocal supersets are a method of resistance training that alternates multiple sets of high-intensity agonist-antagonist muscle groups with limited recovery, like the ones done in Cross fit, P90 workout, Insanity: Asylum and other “muscle confusion” workouts.

The question is does introducing muscle confusion (compound exercises and reciprocal supersets) improve results in terms of weight loss and muscle growth, strength, performance…

Recently an experiment published in the Journal of Strength and Conditioning Research attempted to answer some of these questions.  The study compared the metabolic costs (energy expenditure) of reciprocal supersets vs. traditional resistance exercise. The results found that there was no difference in total energy burned during the workout.  However the reciprocal superset group had higher rates of energy expenditure, oxygen consumption, and blood lactate levels one hour after the workout, and their workout was completed in a significantly shorter time period.

Therefore the results of this study support the idea that a high-intensity short duration interval-training program increases energy expenditure rate (calories burned) in a shorter amount of time while also increasing metabolism after the workout as well.

Muscle confusion in the context of introducing agonist versus antagonist supersets

Besides being incredibly time-efficient supersets take advantage of one of the most fundamental principles of exercise science called the Sherrington’s Law of Reciprocal Innervation, which states:

When a contraction of a muscle is stimulated, there is a simultaneous inhibition of its antagonist. It is essential for coordinated movement.

Agonists Supersets pair two competitive exercises together (i.e., Chest Flyes & Push-ups), while Antagonist Supersets pair two non-competitive, opposing (antagonist) exercises together (i.e., Push-ups & Rows).

As a matter of fact, even the great bodybuilding legend Arnold Schwarzenegger, under the tutelage of fitness pioneer, Joe Weider, regularly employed supersets in his bodybuilding routines.

In order to experience this law first hand, go and fully extend one of your legs, then squeeze your quad muscles as hard as you can and notice how relaxed your hamstring muscles (the opposing muscles) become. If this reciprocal inhibition didn’t occur you’d be a total mess who’d move spastically throughout the day with all your muscles firing uncontrollably.

The fact is, the more relaxed your muscles are between one work period and another, the faster they can recover for the next round. This improved recovery in turn boosts exercise performance (what programs like Insanity and Insanity: Asylum promote) which ultimately leads to greater strength and muscle gains, a faster metabolism, increased fat burning, and voila- a great looking body.

Muscle confusion in the context of performance

As we stated earlier, reciprocal supersets, both agonist as well as antagonist, together with compound exercises as a whole provide for better athletic performance.

This is due to the fact that hypertrophy occurs when we are stressing the muscle. But knowing that the muscle fibers are not unilateral in the sense of being shaped into one direction it comes as a no surprise that “hitting the muscle” from various angles promotes more of a hypertrophy.
Muscle confusion and performance

This type of exercising, as well as changing it constantly achieves exactly that.

The more angles you stress the muscle from, the better the results performance wise.

The opposing statement, on the other hand, is that such type of training is limiting your specific performance i.e. maximum amount of push-ups that you can make (strength), or the time in which you can finish a mile (speed and endurance).

However, changing the exercises in such a manner (adding not only various combinations of compound exercises for strength through resistance, but different types of balance and endurance exercises as well) provides for hypertrophy from all possible angles, as well as improved range of motion- something that makes a huge difference when it comes to athletic performance.

A study conducted at the Journal of Sports Sciences by Folland, Hawker, Leach, Little and Jones, suggests that even isometric training may improve strength and conditioning more than dynamic training if done from various angles.

Exercising with the vertical of performance in mind it is also wise to pay attention to new moves and coordination, since it promotes “teaching the muscles” new patterns of movement and different ways in which to contract the muscle fiber by hitting it from various angles.

Another thing, performance depends on the type of muscles being used. And knowing that there are two types: fast-twitch and slow-twitch muscles, it is wise to train both of them simultaneously. Muscle confusion, when referred to from a performance point of view tackles upon this very question.

Strength training activates the fast-twitch muscles, whereas endurance training focuses upon the slow-twitch ones. And this is only the tip of the iceberg; so going from one type of training to another really does make some sense.

Muscle confusion in the context of escaping plateaus in weight loss and muscle gain

muscle confusion and weight lossChanging the nature of the exercises and switching from compound to isolated or from agonist to antagonist supersets, or by adding intensity in the form of shorter rest, more repetitions or heavier weight creates more of a stress to the muscle and a bigger increase in metabolism and calories burned.

Weight loss happens as a result of calorie deficit. And there is really no more to it than this. You can achieve it by eating fewer calories, burning more calories or a combination of the two.

When it comes to weight loss besides from pulling strings from muscle hypertrophy, muscle confusion gives additional boost by introducing everything of the above.

As for building muscle, that, we covered as well.

Conclusion regarding the concept of muscle confusion

My first advice is not to pay attention to the semantics. With that aside, it becomes clear that different words provide context when you cross reference one finding with another. Oh, and if skipped the article and somehow ended here fearing that it is TLDNR, I advise you to scroll back up and forget about this summary- the concept is being discussed above, and into detail too.

The concept of muscle confusion is admittedly complex and bears careful consideration, but from the progress point of view it is rather simple.

It is also about performance, avoiding boredom, avoiding injury, creating an all-round muscle definition applying stress and evoking hypertrophy.

A fellow blogger had said it very well too:

To me, muscle confusion is not only about implementing variety in your workouts, but is even more about discovering major weaknesses in your muscles, exposing coordination issues with them, and then hammering out a routine to get these weaknesses and uncoordinated movements removed, or improved, as quickly as possible. ~ Larry Van Such

It all depends from which perspective you choose to observe the term muscle confusion, since it’s undisputedly about changing your training routine in the hope of seeing better results, but it’s all about semantics from there on. I hope the various cross references with some concepts and studies have shed some light when trying to understand what muscle confusion really is.


–         Kelleher AR, Hackney KJ, Fairchild TJ, Keslacy S, Ploutz-Snyder LL. The metabolic costs of reciprocal supersets vs. traditional resistance exercise in young recreationally active adults. J Strength Cond Res. 2010 Apr;24(4):1043-51.

–         American Council on Exercise: Weight Loss Plateaus and Pitfalls

– Hypertrophy — The Mechanics of Muscle Growth

– Muscle Building — Hypertrophy and Physiology

–         Folland JP, Hawker K, Leach B, Little T, Jones DA. Strength training: isometric training at a range of joint angles versus dynamic training- Source- School of Sport and Exercise Sciences, Loughborough University, Loughborough, UK

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