Will my muscle come back faster after a long break?
One model says yes: nuclei gained while growing are kept through atrophy and speed regrowth. Shown in rodents; the author calls the human case an "if", and it is disputed.
Gundersen reviews the idea that skeletal muscle has a cellular memory of past hypertrophy: a fibre that was once large and has since lost mass can regain it faster than a fibre that was never trained. He proposes a cell-biological model built from the literature that uses what he calls the most reliable methods for identifying myonuclei.
In the model, previously untrained fibres recruit new nuclei from activated satellite cells before they grow; when the fibre later atrophies, even severely, the higher number of nuclei is retained, and the nuclei seem protected against the raised apoptotic activity seen in atrophying muscle tissue; when overload returns, fibres with more nuclei grow faster, so the nuclei are a functionally important memory of previous strength.
Because myonuclei in humans are stable for at least 15 years and might be permanent, the memory might be very long-lasting in humans; since nuclei are harder to recruit in the elderly, the author suggests that, if this memory exists in humans, early strength training should be public-health advice.
Steroid use also recruits myonuclei and encodes a memory, at least in rodents, so he suggests extending the exclusion time for doping offenders. Our reading: this is the clearest statement of the myonuclear side of the muscle-memory dispute, and its human case is explicitly conditional.
A human trial by Psilander, with Gundersen as senior author, found no faster regrowth in a previously trained leg, but training had added no nuclei in the first place, so it could not test the model (REF-1360); the other side holds that newly gained nuclei can be lost on detraining, in mice (REF-1143).
The base therefore cites this model as one position, not as a reason to promise an athlete a faster comeback.
Protocol
Key Results
| Step of the model (abstract) | What the author states | Shown in |
|---|---|---|
| Before hypertrophy | untrained fibres recruit myonuclei from activated satellite cells | animal studies (implied; species not named in the abstract except for steroids) |
| During atrophy | the higher number of myonuclei is retained, even after grave atrophy; nuclei seem protected from the elevated apoptosis of atrophying muscle | animal studies (implied) |
| On renewed overload | fibres with more myonuclei grow faster — the nuclei are a "memory" of previous strength | animal studies (implied) |
| How long in humans? | "might be very long lasting", as human myonuclei are stable for at least 15 years and might be permanent | human data cited; memory itself not shown in humans ("if ... also exists in humans") |
| Ageing | myonuclei are harder to recruit in the elderly → early strength training as public-health advice, if the memory exists in humans | the author's recommendation |
| Steroids | recruit myonuclei and encode a memory, at least in rodents → extend doping exclusion times | rodents |
Mechanisms
Practical Application
Limitations
How this entry was checked and changed
a narrative review whose human claim rests on rodent data (the rubric's C), held at C+ although it comes from the leading group on myonuclear memory; it falls below B+ because the model's central evidence is animal work, largely from the author's own laboratory (the abstract states the human case as "if the long-lasting muscle memory also exists in humans"; the rodent data are C-grade evidence for a human claim), and the model is disputed: a human retraining trial from the same group found no memory effect, though it did not add nuclei to test it (REF-1360), and a 2026 conference summary reports that in mice newly gained nuclei can be lost on detraining (REF-1143). Read from the abstract (closed access; Europe PMC holds no full text, OpenAlex marks it closed, and the publisher link it lists returned a Cloudflare block, which was not bypassed)