T Nation

Muscle Memory: Fact or Bro-Theory?


Is "muscle memory" a scientifically studied/proven idea or does that fall into the same (controversial on T Nation) bucket as weight "set points"?



Scientific and a fact. It's a neurological phenomenon.


Myonuclei acquired by overload exercise precede hypertrophy and are not lost on detraining
J. C. Bruusgaard, I. B. Johansen, I. M. Egner, Z. A. Rana, and K. Gundersen1
Author Affiliations

Edited by Gerald D. Fischbach, The Simons Foundation, New York, NY, and approved July 16, 2010 (received for review December 4, 2009)

Effects of previous strength training can be long-lived, even after prolonged subsequent inactivity, and retraining is facilitated by a previous training episode. Traditionally, such ?muscle memory? has been attributed to neural factors in the absence of any identified local memory mechanism in the muscle tissue. We have used in vivo imaging techniques to study live myonuclei belonging to distinct muscle fibers and observe that new myonuclei are added before any major increase in size during overload. The old and newly acquired nuclei are retained during severe atrophy caused by subsequent denervation lasting for a considerable period of the animal?s lifespan. The myonuclei seem to be protected from the high apoptotic activity found in inactive muscle tissue. A hypertrophy episode leading to a lasting elevated number of myonuclei retarded disuse atrophy, and the nuclei could serve as a cell biological substrate for such memory. Because the ability to create myonuclei is impaired in the elderly, individuals may benefit from strength training at an early age, and because anabolic steroids facilitate more myonuclei, nuclear permanency may also have implications for exclusion periods after a doping offense.


So it's muscular and neurological in nature.


Super fact.


That was easy!

So, why couldn't this tie over into "set point"? Isn't it a similar phenomenon that one's mass watermark (for lack of a better term) is raised as more muscle is put on and held.

For the record, I hold no particular stance on this either way, but it seems that the two could possibly be similar. Anyone looking for a master's thesis or PHD dissertion wanna tackle this hypothesis?


I had a weird experience with this the other day, I've played rugby ever since I was 10 and once I turned 15 it got serious and I had hopes of turning pro. Anyway I knew that as a small kid (I had just hit puberty haha) I knew that I'd get my ass kicked with physicality so I had to stand out with my skills and decision making instead so I trained my ass off with regards to passing, kicking and general ball handling and when I say trained hard it would be all I did when I got home from school or I'd stay after practice for hours on end getting it right...

Anyway to cut a long story short this time last year I came out to Australia for a working holiday and decided to play Aussie rules football instead just for something different, so last week I was at the gym wearing my old rugby shirt and a guy invited me to play in a 7's tournament at thte weekend so I though hell yeah I haven't played for ages! So I was bricking it as I hadn't even touched a rugby ball for 10 months and I thought my skills would've gone to shit but Instead I played awesome! My passing and ball handling was the same as ever and I was hitting my kicks with pin point accuracy, even diffusing the high balls was easier than ever, it was as if I had never taken a break!

Now I've always been a pretty natural sportsman who can pick things up easily but I put that down entirely to hours and hours of practice and muscle memory


That's a different kind of muscle memory(although there might be some overlap in the exact case you're speaking), which is actually far more akin the common association of the word memory.

'Muscle Memory' as far as growing back to a size, regaining strength at a rapid pace, has a lot to do(as Brick's abstract notes) with reparation of neurological pathways after a long period of atrophy which lead to denervation. Neurological adaptation is huge when it comes to strength, and the ability to quicken the regeneration of those pathways leads to a very rapid rebound in ability to recruit muscle fibers, which is very key in their growth. The word memory in this sense is a slight misnomer(not a complete one, it's just most people associate memory with brain activity, recall/recognition, the brains process of encoding).

That's a really interesting road to go down. I've always heard muscle memory referenced in response to periods of serious muscle atrophy(for the myriad reasons it may occur), or as an effect of previously experienced supraphysiological conditions(steroid use) and the bodies ability to then 'remember' and retain some of the previous condition even though (hormone levels in this case) have returned to normal. Thinking of it that way, it sounds entirely plausible that as long as some beneficial neural adaptation has taken place while the body is heavier, that a future leaner version of the same person should be able to return to that state again(or at least approach it easier, as with the steroid example returning exactly to that state or maintaining it will be impossible because physiological conditions have changed and limit it in some form).

Sorry for semi-walls of text. Also, I'm not a PhD in the field being discussed, just someone who reads research for self education and (nerd alert) fun.


The problem with getting very heavy and sacrificing body comp the body also has set points for fat. And literally everything else for that matter it learns to adapt. Stay at a higher fat for a long time and the body sets that as the new norm.


Doesn't this have something to do with fat cells dividing and multiplying which makes rapid fat gain easier in the future?


That is one thing that can happen. Fat is an endocrine organ by itself so it is constantly making hormones and some of these will contribute to the set point also the hypothalamus will be involved. Sets points are quite complex and certainly a lot has yet to be learned


Is that a known?

My (very rudimentary) understanding of fat cells is that, barring extreme obesity where new fat cells are produced (no, not T-Nation 18% fat obeseity, but WalMart scooter obesity), the body produces X number of fat cells (ie genetic blueprint), and the expression of that fat from a composition standpoint is the size of the fat cells -- ie. when you diet off fat, you don't lose fat cells, you shrink the volume of fat they are holding.

I'm contrasting that with muscle loss where (I assume) you are actually losing muscle cells and then rebuilding them.

If you're alluding to "fat setpoints" meaning the set point size of the fat cell, then that seems to me to be a very different mechanism of 'biological memory' than 'muscle memory'.


I don't know if there's a true 'fat set point', or it's simply a matter of multiple factors that make it much more difficult to lose adipose tissue over time (not saying it's impossible, just not as easily accomplished).

I have heard many laymen use the idea of "muscle memory" describe the neurological adaptation of a repeated motion or task. This however, isn't due to the sudden regrowth of muscle tissue. As Brick mentioned above (in a nice texty-explaination -lol) is that once you've initially built muscle tissue, due to the roles of satellite cells, even when you later lose the muscle, you're left with multiple nuclei within the muscle cells. This can allow for a much quicker synthesis of new tissue ("regaining lost muscle") later on.

As I'm still recovering from shoulder surgery, the rate of muscle as well as strength regained, has been interesting to observe. While the strength levels are coming back in a very uneven manner (some bodyparts rather quickly, and others still chugging along), the size gains just the last couple of months has been very noticeable. Certainly at a much more accelerated rate than the years it took to gain the size initially.



There are studies showing only in obesity and others that show its not close to obesity when the fat cells split. More research is needed

Yes when dieting you are not killing fat cells though there are ways to kill them but its not easy

The muscle cells to my knowledge don't die either they shrink but from training and previous expansion they have increased the number of nuclei which allow for the rapid expansion when training and food are brought back up after a time of atrophy. Plz correct me if I am wrong I have not done much reading on this subject.

If that is the case I would say fat set point and muscle set point are quite similar


The way it was explained to me is that it takes the body a lot of energy to create new cells, therefore it's very reluctant to let go of them once they're no longer required. It's far more efficient to let them sit empty, and then rapidly refill them as required.

My personal experience is that this is true with both fat and muscle. I let my body atrophy from 2009 to 2012. It only took 8 weeks of lifting to return to and surpass former strength milestones.


While both fat and muscle cells seem to have, in a very general sense, the same mechanisms for growth - growing larger, I don't think this necessarily translates into the same "memory" for size.

Muscle cells adding nuclei seem primed for growth because of the increased receptors available. The only equivalent in fat cells seems to be the creation of entirely new cells. While I seriously doubt that fat cell creation/division has a distinct starting point at X%/obesity/whatever, it does seem to be a very minor factor until one reaches appreciable amounts of fat.

But this is me making a pretty uneducated guess ...


I think the bodyweight/fat set point has more to do with the overall hormones the hypothalamus has been subjected to and wants to keep homeostasis after its recieved that signal for quite some time including the hormones it has been subjected to from fat cells. (Central nervous system chapter was the most difficult part of anatomy 1 for me, probably need to read it again.)

While if you atrophy you really don't lose muscle cells you just reduce the size of the muscle cells and the number of myofibrils they contain while in Brick's abstract they keep the nuclei and other stuff. In general when you get bigger muscles the number of muscle cells stays the same just the cells get bigger and have more myofibrils in the cells.

Edit: Even my book says muscle hyperplasia is hotly debated. (Human A&P 9th Marieb,Hoenh)


I had it explained in more laymen terms. Basically think of your neural pathways as a street. With bigger muscles the street must get wider and expand. So if you end up with a 8 lane highway and stop lifting or atrophy the muscle, that highway is still there as the nerves stay in tact. So, when lifting resumes the muscle contraction and use is amplified by the amount of neural pathways being optimized.


That's kind of accurate. The neural pathways can be broken, but the nuclei remain in the cell. It's more like, winter time can come and cause potholes and really fuck up your highway(atrophy and denervation), but fixing it up is a hell of a lot faster than rebuilding the whole highway.

Since there was some confusion about how the cells are formed/lost: new nuclei come about from a process of the myofibril fusing with satellite cells. The satellite cells have the ability to replicate(moderated by numerous growth factors), retaining a cell to continue acting as an organelle to the fiber(and continue splitting in the future), making it larger to begin with, but also giving it more ability to expand actin/myosin filaments and add neural attachments. The end result is a larger and more powerful piece of a motor unit. This is also part of the process for repairing muscle(not always adding a nuclei).

Again as in a previous post, it's entirely plausible that being heavier lays some groundwork for getting back some potentially lost mass during a cut(I know I know you barely lose any if you do it right) at an accelerated rate, but that your body will get back to a specific weight sans the fat seems incorrect, because the muscle would be going beyond what it was(not that it couldn't eventually, but this wouldn't be 'memory'). There are a ton of variables that would complicate researching this, primarily the variance of hormonal levels and receptors if the difference in fat mass is significant(say, a hefty cut followed by a 'rebound' -post contest or otherwise).


It is my, rather limited, understanding there probably is, and some evidence for, a sort of general endocrine "set point." It does seem that this is rather poorly understood, and may or may not be influenced by fat and/or weight fluctuations.

It seems that in the absence of the extremely calorie dense "foods" available today one would maintain a relatively stable body weight throughout most of adulthood (and many still do). Some studies seem to have temporarily introduced such "foods" into cultures without access and saw significant increases in both weight and fat, with individuals returning to baseline with the removal of these "foods."

While I am really just guessing again, it appears the "set point" may be a genetically determined force that is only strong in one direction, when body fat drops below whatever preditermined range. It does still seem to apply weak pressure to drive weight/fat down if given a chance. It would also seem (more pure conjecture) that resistance training seems to be able to somewhat uncouple weight from fat, giving one the ability to weigh more at the same body fat.