Why Muscle ‘Grows Back More Quickly’ – It’s Not Muscle Memory!

By on January 3, 2016

On a couple of occasions throughout my life, I have been forced to take a hiatus from the gym. This happened for instance when I was 15 and I broke my wrist in half (I started working out early) which forced me to give up my exercise habits for around three months (which my Mum saw as a silver lining).

On such occasions I was assured by everyone who saw me looking morose, that it was much easier to ‘regain’ muscle and that my biceps and pecs would be back in no time at all thanks to something called ‘muscle memory’. And it seems I’m not the only person who has been told this; check any bodybuilding forum or fitness video on YouTube and you’ll be told with authority that muscle grows back thanks to ‘muscle memory’.


What you won’t find quite so easily however, is any kind of description regarding what this magical ‘muscle memory’ is, or where it comes from.  If you look up what muscle memory actually means in fact, it has nothing to do with strength gains or bodybuilding. What’s it’s actually about, is strengthening the neural networks when you go through the same movement repeatedly. That’s what muscle memory means – it has nothing to do with bulging biceps. So is this all just a big misunderstanding? Is it a myth based on someone’s poor assumption of what a word means?

Muscle Memory for Learning

The usual definition of muscle memory then is much more to do with learning repetitive behaviours rather than building strength. Muscle memory is the reason you never forget how to ride a bike and it’s the reason that people who have lost all their ‘episodic’ memories can still remember how to play the piano. Muscle memory will help you to perform the perfect golf swing, to perform dance choreography that you learned years ago, and to block a punch without thinking about it if you’re Bruce Lee.

Actually though, this type of learning has nothing to do with your actual muscles. Learning as you know doesn’t take place in your muscle, it actually takes place in your brain where you have neurons representing different parts of your body.

This type of learning called ‘motor learning’ takes place largely in the cerebellum and occurs as you repeatedly use the same neural networks. Each time a synapse fires, it gets slightly easier for it to fire again next time. Or as they say, ‘neurons that fire together, wire together’. Eventually, you have a whole range of solidified neural networks that fire almost automatically whenever you begin going through certain motions allowing you to play the piano, run, jump and type. In most processes, this involves an element of feedback through the senses and of mental models regarding how movements should be performed. I’ve discussed all this in more detail though in articles on brain plasticity and the nervous system.

Muscle Memory and Hypertrophy

So that’s what biologist will be thinking if you start talking to them about muscle memory and it’s what the term ‘officially’ refers to. The question that bodybuilders and athletes should be asking themselves though, is whether there’s another type of ‘memory’ in the muscle that makes it easier for it to grow (the process of growth is called hypertrophy) if it has previously been bulked up.

On the face of it, you would probably assume that there’s no truth behind this belief seeing as everyone is mistakenly calling it muscle memory. Actually though, anecdotal evidence suggests that regaining muscle is easier than gaining it for the first time – and this is also what I have found to be true in my own experience. When I’ve taken time off and I then get back into the gym, I will generally find myself gaining muscle much more rapidly than most complete beginners. That’s despite their ‘noob gains’.

So if that’s not muscle memory then… what is it?

The Science of Regaining Muscle

Morning_arms_workout_with_my_new_Microsoft_Band__Felt_like_a_bit_of_a_creep_with_my_camera...__workout__biceps__hammercurls__microsoftband__fitnesstracking__bodybuilding__armsdayWell unfortunately the official answer to this question is: nobody is really quite sure. It’s generally accepted that there is a mechanism for regaining muscle but research on the topic is limited and there’s no one theory that’s widely accepted by everyone.

That said, there are a few suggestions that may go some way to explaining why we find it easier to put muscle back on if we’ve previously been strong and there are a few other factors to consider here too…

Actual Muscle Memory: The first thing to take into account here is muscle memory… ironically. While muscle memory doesn’t directly having anything to do with growth in your muscles, what it does do is to help you remember correct form when lifting weights, making you more efficient and improving your ability to hold them steady.

What that means is that in theory you will still be able to lift heavier weights than you otherwise would even when you’ve lost some muscle, because you’ll have more of a natural inclination as to how you should be holding them. If you can more quickly increase your weights then, it only follows that this would help you to accomplish more rapid muscle growth too.

Why Muscle ‘Grows Back’ Quicker

Experience: This goes more generally for you overall experience too. If you have previously been a regular gym rat, then no doubt you will have some idea about how to eat correctly, how to create effective workouts and how to recognise when you are actually building muscle versus just wasting your time. Again this will allow you to train much more efficiently, to stick to your goals better and to ultimately see more impressive results in a shorter time period. This is less muscle memory and more ‘memory of muscle’.

Nuclei: Training also improves the ‘mind muscle connection’ – which is our ability to recruit more muscle fibres during a lift. The more efficiently you can do this – which is achieved through training – the more power you can generate.

Some people doubt the existence of the mind muscle connection, or the fact that it can be trained. To that I say: then why can only some people wiggle their ears? We all have muscles that can move our ears but only some of us have the mind-muscle connection necessary to move them! You can train yourself to move you ears simply by continuously trying. Likewise, some people have trained themselves to be able to affect more of their motor units in each primary mover.

Weight training strengthens this mind-muscle connection and this is the reason that strength gains can actually precede increases in muscle size.

How this works is complex but there are a couple of factors. One is repeated use of the neuromuscular junction which is the synapse between the nerve and the muscle fibers. When our brain commands movement, a signal is sent through the nervous system resulting in the release of acetylcholine at the neuromuscular junction, which is received in turn by the nicotinic receptors in the muscle triggering the contraction of muscle.


Using the muscle helps us to improve this connection and thus increase the amount of strength we can get from the same amount of muscle. Part of this may be due to neuroplasticity, though it also likely has to do with increases in nuclei in the muscle (known as myonuclei). New nuclei are formed in the muscle fibres in response to training and this results in improved synaptic efficiency or signaling (1). While a lack of exercise will let the physical mass of the muscle atrophy, you won’t actually lose those new nuclei. This means you will retain some of your additional strength even when your muscles are visibly smaller, and that you’ll find it easier to lift again when returning to the gym. Better yet, because the increase in nuclei increases your protein synthesis, that means that you can add mass more quickly that way too.

Normally when you train you must add new nuclei to your muscles and then provide them with protein to help bulk up the fibres. If you’ve been strong before though, then you get to skip straight to that second step and you’ll start absorbing more protein right from the start.

Fascia: Another element that might contribute to more rapid muscle gain is the stretching of the fascia that surround the muscles. Essentially your muscle fibres are surrounded by a network of fibrous tissue called the fascia which works to help support you through your movements but which some people believe can also limit muscle size by not giving them the space they need to grow. Think of this fascia like cling film wrapped tightly around some meat.

One theory based on this belief then, is that building big muscles for the first time will help you to ‘stretch’ the fascia and that this takes a lot of work. Then, when you return to the gym later, because the fascia is already stretched, you won’t have as much of a hard time trying to build the muscle up to that point again. There was a time when bodybuilders recommended using a particular type of stretching prior to workouts and competitions for this very reason. This is just a theory however though and there’s little evidence to support or contradict it. Still though, if there’s any truth in it then it certainly can’t hurt!

Water Retention: Another point to consider is that some of the muscle you lose after you stop working out isn’t really muscle… Stop working out for a very short amount of time and you will notice relatively immediate losses in size and firmness in your muscles for the same reason that your muscles look much bigger after a workout.

That’s because when you’re training or recovering from training, the body rushes fluids to the muscles you’ve used in order to make sure you have enough nutrients there to keep them going and to make the repairs. When you stop working out, your body won’t need these fluids anymore and so it will drop them pretty quickly. Likewise though, your muscles will also swell up pretty fast when you start training again, and this will be more noticeable if you still have slightly larger musculature in place.


So there you have it. ‘Muscle memory’ is definitely a misnomer but the general consensus is that muscle will grow back more quickly when you’re building it for a second time due to a number of different factors including increased synaptic efficiency, more nuclei in the muscle fibers resulting in better protein synthesis and water retention. Consume lots of protein (even more than you would as a beginner), start with slightly heavier weights and try to fall back into your old routine. That way, you should find that you get back to where you were in record time!


About Adam Sinicki

Adam Sinicki, AKA The Bioneer, is a writer, personal trainer, author, entrepreneur, and web developer. I've been writing about health, psychology, and fitness for the past 10+ years and have a fascination with the limits of human performance. When I'm not running my online businesses or training, I love sandwiches, computer games, comics, and hanging out with my family.

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