What Is Muscle Memory? - Habit 52 x Air Gymwear

After long periods of gym closures and the inevitable return to resistance training, the muscle memory conversation has reappeared and confused people once more but by the time you finish this article, hopefully you will have a better understand at what muscle memory means. 

Absences from weight training means many of us have lost strength and our once heroically sized muscles have atrophied. It’s time to regain the gains and this is where muscle memory comes into play.

What Does Muscle Memory Mean?

There are two meanings associated with the term “muscle memory”, which is how it becomes confusing.  

Muscle memory either refers to the notion of muscle rebound, where hypertrophy takes place more readily if that muscle has been built before, the other connotation refers to motor pathway performance that is, without pointing out the obvious, initiated for movement patterns. If that sounds confusing - fear not, it has been simplified and explained below with examples, so that this conundrum can finally be put to rest. 

Muscle Rebound Memory

The one we all want to be true, but does the evidence stand up to the hopes that we can have a quick resurgence of lost muscle? There are a couple of factors to consider alongside the scientific support. 

We see this happen with beginners, when resistance training is unknown to the body, the response is lean tissue development over a relatively short period of time; otherwise known as newbie gains. 

The ‘Use it or Lose it’ principle of hypertrophy, tells us when the muscles aren’t used they are lost. However, do we have newbie gains 2.0, after muscle loss, when restarting with a resistance training programme, as if we’ve had a refresh and starting anew once more? 

The evidence suggests that it is possible and that our genes have an epigenetic memory of previous muscle size1. Even though muscle fibres are reduced (quickest rate of loss in the first 4 weeks of detraining), the motor unit recruitment decrease is not as quick. This means motor unit recruitment is greater for the muscle than when it was previously that size and therefore can develop muscle quickly.

This increase in hypertrophy only relates to reaching the same muscle size before the break from training and does not mean that increased rate will carry over to building new muscle2. 

Other factors, to name a couple, that influence size of muscles are blood flow and carbs. The glorious pump lifting provides produces an increased muscle size aesthetically. When regular volume and strength training fully resumes, the semi-permanent pump state that keeps muscles looking full sets back in. This occurs because an increased blood flow is necessary for recovery

Of course, this in only appearance and superficial size and does not relate to muscle fibre and cell increase.

Similarly, carbohydrate consumption and storage in muscles can also superficially increase size. A return to a training programme also brings along a return to healthier eating habits, some of which for performance sake means an increase in carbs. 

Carbs are digested and stored in the muscles as glycogen and used for energy3. These glycogen stores are depleted when muscle is used. During the reloading phase, after a break from training, an increased carb intake means muscle glycogen stores will increase and will correspond with an increase of the superficial size of muscles. 

Muscle Movement Memory

The second type of muscle memory concerns the use of motor neuron pathways rather than motor units and muscle fibres. 

This one can be pretty complicated, but it’s essentially about learning a movement pathway, which can be as simple as a bicep curl or as complex as riding a bike. 

Each movement has an associated movement pathway. Riding a bike has many different movements that become once complete process, a schema if you like (a group of movements that form a whole, along with a whole bunch of other motor programming).

When a new skill like riding a bike, driving a car or even button combinations when playing video games occur the desired outcome isn’t always as efficient or smooth as expected. 

Kids learning to ride bikes can do all the movements but the application of those movements haven’t been reinforced together; they shake and wobble and fail… a lot. With practice and perseverance, they eventually master the movements necessary. 

The more the specific movement pathway is used for an activity the stronger the link between movement programme and the muscle output of that activity will be, until it is second nature. 

Think of each movement programme and schema as a save file in your body for specific actions. When frequently used, it is always readily available and that means movement is smooth and consistent. 

However, ‘Use it or Lose it’ applies here too. After a period of time when this motor programme isn’t used then this save file, although still available, doesn’t provide as strong a link and is sometimes harder to find and establish. 

You can get on and ride a bike but it may be shaky at the start if you haven’t done it in years. The same occurs with gym movements, especially compound lifts that require many actions, such as a clean and press. 

After an absence to the gym, the movements that were second nature may be a little shaky and that’s normal. Taking some time to re-establish those movements and re-strengthen the link and kinaesthetic feeling once more is easy, it just requires practice. 

The memory of these movements is enduring but may just take a minute to find. 

To summarise: after a period of detraining where the muscles are not being activated and the movement patterns aren’t used, you will have less muscle size and less efficient movement. It sounds like bad news, however, our muscle memory, whether it’s size or performance, exists. 

More so, muscle rebound happens quickly, over a couple weeks, plus the movement patterns are re-established much faster, as long as repetition is consistent. With weight training being repetition based a session or two of careful lifting should see a resurgence of normal movement performance.  

1. https://pubmed.ncbi.nlm.nih.gov/29382913/

2. https://medium.com/@SandCResearch/how-does-taking-a-break-from-strength-training-affect-hypertrophy-de969bc7ab66 

3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3248697/

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