Numerous individuals who were once active in their youth often find themselves unintentionally taking a prolonged hiatus from sports in adulthood. Perhaps you engaged in weightlifting during your teens and 20s, only to pause due to family commitments until your mid-40s. Frequently, you’ll notice that your original strength and training capacity return surprisingly quickly.
My deep contemplation on muscle memory began while watching the film “14 Peaks,” featuring Nims Purja, a Nepali mountaineer who conquered all 14 mountains exceeding 8,000 meters in 2019. As a former Ghurka and British Special Forces trooper, Purja possessed the physical resilience necessary for such a feat.
Curiously, the film commences with a somewhat out-of-shape Purja reluctantly commencing his journey towards fitness by hoisting sandbags. It appears he had taken a significant hiatus from physical activity, evident by his ample midsection.
Many individuals in their late 30s facing this situation might consider giving up. Yet, Purja showcases a seemingly implausible “comeback,” achieving his incredible mission within six months and six days – even doing so on a day after having a hangover. Is Purja a superhuman? To some extent, yes. However, the potential for the body to recollect its past capabilities might not be as inaccessible to us as it appears.
While it’s tempting to assume that Purja possesses an exceptional psychological disposition tailored to conquer the world’s tallest peaks (which he does), it turns out that muscle memory – the ability of muscles to recall their past strength – is a genuine phenomenon.
I recently conversed with two researchers – Professors Kristian Gundersen in Norway and Lawrence Schwartz in Massachusetts – whose groundbreaking research sheds light on what might actually be occurring when you feel as though your muscles are remembering activities you once engaged in. As it appears, the well-known notion of ‘use it or lose it’ may not encapsulate the entire truth of training’s impact.
The Concept of Muscle Memory First and foremost, both scientists clarify the misunderstanding surrounding the term “muscle memory.” Many compare it to riding a bicycle or a former gymnast performing a perfect backflip after a decade-long hiatus. However, it turns out that this form of recollection is rooted in the nervous system, not the muscles themselves.
Regarding the ability to regain strength that seemed lost due to time and inactivity, “muscle memory” pertains to the potential to regain muscle mass and strength in muscles that were previously trained. Both scientists conducted laboratory research indicating long-term structural changes in muscles through short-term training, as observed in moths and mice.
Schwartz’s research isn’t focused on humans – in fact, he intentionally avoids mammals – but his study on cell death led him to intriguing conclusions about muscle memory while studying tobacco hawk moths. These moths experience a dramatic increase in size during their lifecycle. Schwartz noted that the abdominal muscles of these moths displayed a significant regrowth in muscle mass and volume despite a prior atrophy phase.
Around the same time in 2010, Gundersen conducted an experiment on mice that revealed when muscles atrophy, they become smaller, but the number of nuclei within the muscle remains constant.
Gundersen administered testosterone to mice for two weeks to artificially increase their leg muscle mass. After a three-month hiatus – equivalent to a substantial break for mice – their leg muscles atrophied and were similar in size to the control group. Upon retraining, the muscles of the testosterone-treated mice exhibited rapid growth – by 36 percent.
“It was a rather strong effect. They harbored some kind of muscle memory that made it easier for us to retrain them,” Gundersen explained.
Gundersen’s surprising findings challenge the notion that muscle tissue doesn’t regenerate. Unlike other cells, muscle nuclei remain intact, akin to a closed factory that can reopen and produce protein.
The Role of Nuclei in Muscle Memory The explanation for this phenomenon revolves around cell nuclei – repositories of genetic information and the cell’s command center. During exercise, stem cells increase the number of nuclei to facilitate protein synthesis.
Contrary to previous beliefs that nuclei are lost upon training cessation, Gundersen likens the process to a factory within cells. The nuclei remain, allowing for quicker muscle protein production when training resumes.
In the context of starting to exercise, new nuclei need to be produced in muscle fibers – akin to establishing a factory, hiring staff, and initiating production all at once. Resuming training is akin to reopening the factory doors and restarting production.
However, these findings’ applicability to humans necessitates further investigation. Gundersen acknowledges the need for a 15-year study to determine their relevance to humans and their applicability to endurance and strength training.
The Implications of Muscle Memory The adage “use it or lose it” echoes through fitness circles, emphasizing the importance of consistency. Yet, if these findings hold true, individuals may restore some or all of their previous conditioning even after a prolonged training break.
Gundersen suggests that while an active lifestyle prevails, those who were initially strong may afford to occasionally lose strength due to life events like parenthood, illness, or injury. These findings may ease the anxiety associated with training breaks, as muscles appear to retain their past experiences.
Moreover, implications extend to athletes who resort to doping. If the nuclei retention theory applies to humans, those who cease doping but retain nuclei could gain an advantage upon resuming training. This speculation could lead to longer exclusion times for doping offenders.
In essence, while these revelations require further confirmation, they unveil the potential for our bodies to “remember” past strength and training.