Muscle memory is what? We all know that if you lift weights and stop lifting for a few months (3-6 months), you will lose strength and muscle. However, if you start training back again, you gain the lost muscle or strength within a few weeks - as if the muscle remembers where you left off. This phenomenon is called ‘muscle memory’.

We used to believe this is largely due to the nervous system mechanisms. The nervous system mechanisms may explain the strength gains, but it doesn’t explain how you can gain back the muscle size so quickly.

But recent studies show that we may have finally solved the mystery of muscle memory

Unlike other cells, muscle cells have more than one nucleus (probably thousands). So why do muscles need so many nuclei? The nucleus is basically what controls the cell and since your muscles are a lot lot bigger and way more complex than other cells in the body, one or two nuclei just cannot do the job. So when your muscles get bigger, you have to add more muscle nucleus. The increase in nucleus with muscle growth has been shown in number of studies. It has been shown that people who take steroids and people who grow muscle easily have lot more muscle nuclei than normal.

Just like muscle growth, we believed that when we lose muscle, the opposite happens - we lose some nuclei since there is no reason for the extra nuclei to sit around. And this was supported in studies which showed as muscle shrinks in size, the number of nucleus decreases too.

Now here comes the surprise.

However, recently, studies using different animal models (denervation, unloading, synergic ablation) showed that as muscle atrophies or shrinks due to inactivity or detraining (until 3 months), there is no loss of muscle nuclei as we previously thought! As shown in the picture, the muscle size decreased by 50% (lines) but the muscle nuclie count (stained with green dye) remained the same.

So what? Since now the muscle has the same number of muscle nuclei after we stopped training, it is easy to build the muscle back to its previous size. So these muscle nuclei seems to acts like ‘memory cells’. They know how much muscle you had before you stooped training.

The recent studies used a different technique to study these nuclei.

In previous studies they were counting nuclei which belonged to the connective tissue and other cells (satellite cells). And these nuclei do die with detraining. So researchers mistakenly assumed that the muscle nuclei die with muscle loss. But these weren’t actual muscle nuclei. The recent studies only counted the actual muscle nuclei and showed no loss .

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| Very cool research.

Anoop | Thanks Byron for the comment. Yep it’s really cool. This could be one reason why people who took steroids still look big even after they stopped using it years back. And the authors speculate it would be good for people to start weight training before they get old and start ‘storing’ some myonuclei. Once you start the ageing process, there is less myonuclei added even if you want.

| great article!

| Great article Anoop! Funny, I saw the recent article too and it made me think up the older article (wasn’t aware of the 2008 article). Gonna share this!

| Nice article. Reminds me of my grad school days:-)

| Great Job again Anoop.

Beside Steriods, is there no other way to add nuclei? Glad I started training when I was younger!

Anoop | Thanks Rob. Thanks Bret! I thought either you or Bret would have posted this before! Thanks Jose for taking the time! Thanks Sully. Creatine has shown to increase satellite cells proliferation and differentiation in vitro and vivo!

| This might explain how Flex Wheeler was able to compete at the 2002 without the use of steroids. His genetics paired with the added nuclei through years of steroid usage was enough to make him look well above natural and place 6th (I think). Im still not 100% sure he was completely clean, but this new research does give more credence to his claim.

Anoop | Hi Bob, Thanks for the comment. I am not sure about it. But if he didn’t take any or had low doses, this may explain some of it. This also explains how bodybuilders who used to compete in the drug level, get off the drugs for years and still hold enough to win natural competitions.

| agree - great article! and great to be back! Patty

Anoop | Hi Patty, Thanks! Good to see you back. Where did you vanish?

| Yes!! We struck gold! Thanks, Anoop.

| I didnt work out for a couple of years ! Lost most of my muscles ! Two months after working out i regained all the muscle mass i ve lost and i am back in my good old condition! Muscles have memory ! Thank you ! Great article

| It’s a great articl,it’s helpful for me to be muscular! thank you Anoop!

| Whoa this is great. I had heard of this in one of Layne Norton’s videos, but this is the first article I’ve seen on it with references. Really fascinating 😊

| Does this mean that since I have never exercised and my muscles are as atrophied as can be while still being functional that I need to lower my expectations as to the level of fitness I hope to achieve? I am 62.

Anoop | Good question. I don’t know how much of a difference it will make. And the best thing you can do is to start as fast as you can.

| Thanks, Anoop. I spent last night scouring this site and many of your references. Today is the proverbial first day of the rest of my life. I learned so much that I have changed up my beginner’s workout program. I am going to start with those basic compound exercises rather than my former long list of isolated exercises. I still have high expectations because I redefined my goals. Thank you so much for helping me.

Anoop | Glad to hear and do register in the forums if you have specific questions. there are other folks who can contribute too. Also look at other barriers that is holding you back.

| “Other barriers”.—thank you for reminding me. I will stay on top of those and I will register in the forum. Thanks so much.

| This is a fascinating read. I took off more than 10 years from the gym, but when I was lifting I was doing substantial weight and had substantial size. 10 years afterward, I was weak as a kitten, but it didn’t take me long to build back up to my previous weights and even surpass them which was a surprise to me. I would have been happy enough to be close. My arms are even at their biggest at 19 inches. I have never taken any PEDs so I figured with age there was no way for me to duplicate what I did in my mid 20’s since I shouldn’t be producing as much testosterone. I read somewhere that every human cell is replaced over 7 years. It would be interesting to see if the results of this study still hold true over long periods of time like my lay off from the gym, and if these muscle nuclei are reproduced as the cells are replaced over time.

| Muscle memory is real. Im now in my 40’s and have not worked out or taken P.E.D. In more than 15years (age 25) as a bodybuilder. Recently ive gotten to be very out of shape and high blood pressure. I always had a 6-pack until i stopped strength training in my early 30s. I just started back in the gym and in the 1st week i can still do 75-80% of my arm strength weight max and chest. My shoulders and legs seem to be the weakest. Iused to squat 405lbs for 10reps and my 1st time back in gym i could only do 135lbs for 10reps two sets.

I think muscle maturity after late 20s helps with hypertrophy and strength. I cant stress enough that if your in your 30s stay with a clean low glycemic index,high protein 1gram per lb bodyweight eating lifestyle (no dieting).

You can lose all your fat with just weight training alone but cardio in morning on an empty stomach or with an E.C.A. Stack can burn up to a couple lbs a week!

Good luck to all the old timers getting back into the gym…

| “These results are yet to be replicated in human studies.” :wow:

Anoop | Yep. It is usually tested in animals and then in humans. And I don’t see any compelling reason why it should be different. But we will have to wait and see.

| What a great read! I am 60 and have been lifting since 21 but have surpassed the weights I used to lift in just about everything. I don’t think it’s ever to late to start building those nuclei.

Anoop | Thanks Laura!

| great article hanks for sharing! isn’t the body amazing? Marc Howard

| Great read , I am 49 haven’t been in a gym for 15 year until last week . I Weight trained throughout my twenties and into my early 30s . I started off weighing about 10 stone and finished off weighing 13.5 stone so 3.5 stone of muscle gain over the years without steroids. I went to the gym last week and managed to bench press 40 kgs this week I benched 55kgs that’s 15kg in a week , and it’s pretty much the same on all my other exercise. There is no way I could have made such a big jump without muscle memory.

I am so please I stored up all those nuclei

| So you are saying that arnold could easily train back to his original form?

Anoop | Hi Radvis, Thanks for the comment He is just too old. Ageing comes with a decline in all those anabolic hormones and other changes in the muscle. So even if he had all those nuclie, he won’t gain all that muscle. Also, it is unsure all the nuclie stays after 20-30 years you know.

| I’ve been average most of my life, female 5’5 started 140 to 150ish pounds in a size 10. Three years ago at 33 I lifted weights and did hiit cardio and got down to 118lbs with 18% body fat and fit in a size 2. I maintained it up until about 8 months ago and I am 131 pounds now in a 4-6. Still some muscle definition but a like more soft and pudgy. Now at 37 am I too far into aging to kick it back in gear and even get better than i was? I feel stupid for a little back slide, and i hope since I’m getting older now, and didn’t get fit and healthy at a younger age that i am now a bit past the point. Thoughts?

| Rachael,

No offence, but that is ridiculous. Gains in muscle mass, fitness, health, almost any measure can be made at any time in life. The key is finding something you like doing that helps motivate you.

Weights and cardio are one way. But an activity that you like can help motivate you to use weights, if beneficial, to enjoy more of your favourite activity. At 42 I still have plenty of room to improve. I expect that to be possible into old age. Check out some YouTube videos of seniors tackling weights for the first time at 60 or 70 and improving. Keep going forward.

Anoop | Hi Rachel, Nope. We have studies done in 90 year olds and showing strength and muscle gains.So 37 is pretty young! And even if you lost some advantage (and which is pure speculation by the author), you will have a lot more to gain than to lose. So be positive and pick up some weights for heaven’s sake 😊 Also check the recent article about older adults and exercise please.

| This use of the term confuses things. It is completely different from the ‘muscle memory’ people refer to as ‘unconscious movement patterns’ which are still entirely thought to be neurological.

| I came across this site while trying to figure out if the effects of steroid use remained years after stopping use. I’ve just started working out again after several years off, but have made fast gains in strength and size. I’ve stopped and started many times over the years, but this is the first time I’ve started back after steroid use. To be honest, it kinda freaks me out that I am making gains this fast…..never happened before when I started back. I used steroids several years ago to recover from several surgeries….had to pass a strength test to return to work. So I’m guessing there’s something to this whole permanent change to muscle nucleus.

| I’m 31 now and used to be muscular and ripped when I was 21. Worked out everyday I could and more that it’s been about a decade since I hit the gym I’m wanting to test this out. The hours I didn’t in the gym I’d what’s been holding me back.

| i trained seriously 20-22 years ago, gained 30 kgs of bulk and was close to entering local bobdyduilding comps – no steroids but was accused because I grew so quick over 12mths

now in my late 40’s and been mostly back to my pre-bulk days weight in the 70-80kg range, whenever i hit the weights now I instantly inflate like a balloon and gain muscle mass very quickly – can put on at a rate of 2kg per week no problem i have always put it down to MM but only just started reading about it i reckon i’d be a great guinea pig or lab study for someone?

| Have been a top national-level female powerlifter for over twenty years. I took over three and a half years off when I hit menopause (no energy, mid-belly weightgain, listless, angry etc). I recently got my ash back in the gym and was very surprised that my deadlifts were still very strong for my age and my size, I was pulling 225lbs as Rep work, with zero problem, and ended my session with 270. I wanted to go heavier (mainly ego) but common sense told me to back off, as my bones are not what they used to be, and I was afraid of a disc fracture. However, the work outs are great, and the familiar feel of a strong reverse grip on a chalk-laden bar made me feel like I never left the gym - best feeling ever! It’s not just muscle memory, but your brain keeps memories too, sound, sight, smell, touch. (ahhh, amonia tabs lol) Even riding the bike and the tread felt pretty good. Just gotta keep my ego in check and stick with it.

Anoop | Hi Kelly, Thank you for the comment! As I wrote in the post, we know pretty much about the nervous system adaptation and how it keeps strength. We just didn’t knew about how muscles can have a memory too.

| I trained for 9 years in the 80s and did get big I’ve lost it all now because I haven’t trained for 25 years but I’m thinking of starting again will muscle memory still be there

Anoop | Hi Collin, Just a great opportunity to see how good your memory is! Try it and let us know.