The science behind muscle memory and why our bodies never really start over
Muscle memory is not just stored in our brains; it is written directly into our muscle cells. We often hear the phrase “like riding a bike,” meaning that once we learn a movement, our bodies never forget it. For a long time, scientists believed that this type of muscle memory lived entirely in the brain, stored in our motor neurons that coordinate movement. While this explanation is partly true, recent discoveries show that it does not tell the whole story. Scientists now know that muscles themselves can remember past training.
Muscle memory inside muscle cells
Muscle memory is not just a metaphor anymore, but a real biological process happening inside muscle cells. When we exercise, our muscle fibers grow larger and stronger. Muscle satellite cells, tiny stem cells unique to muscle, activate in response to stress or exercise. These satellite cells fuse with muscle fibers and donate their nuclei. The added nuclei help control protein production, supporting muscle growth and repair. The remarkable part of this process is that many of these extra nuclei remain in the muscle even after long periods of inactivity, and they do not disappear when stopping, or even returning, to exercise years later. Amazingly, our muscles do not start from scratch. They can rebuild even faster than before, which also explains why people who return to exercise after a long break often regain strength faster than the original process.
Ms. Micaela Von Essen, Performance Training Coach at Pine Crest, explained from her professional experience: “Just like many aspects of the health and fitness industry, muscle memory is created through consistency and repetition. The common expression in the fitness world is that if you don’t use it, you lose it. This is true to an extent. For example, more conditioned athletes returning after two weeks off experience less deconditioned than less experienced athletes. This means they can jump back into workouts at almost the same intensity as before the break. On a cellular level, your body recognizes the work you have put in. When the stimulus (exercise) is reintroduced, your body responds by activating the energy processes needed to fuel your exercise more efficiently. Our bodies crave efficiency. The more we do something, the more muscle memory is developed, allowing our bodies to maximize our workout.”
Groundbreaking research on epigenetics
Much of this groundbreaking research is led by Dr. Adam Sharples, a professor of muscle cell biology at the Norwegian School of Sport Sciences and a former professional rugby player. His work focuses on epigenetics, the study of how behavior and environment affect how genes function without changing the DNA sequence itself. In muscle cells, epigenetics works through chemical markers that act like molecular switches, and exercise can remove small chemical tags, such as methyl groups, from growth-related genes. When these tags are removed, the genes become easier to activate, allowing muscles to grow and adapt more efficiently. Importantly, these epigenetic changes can persist long after our training stops.
In 2018, Dr. Sharples’ lab became the first to show that epigenetic muscle memory also exists in humans, not just in animals. Their studies demonstrated that after strength training, specific gene-expression patterns remain imprinted in muscle tissue for extended periods. These lasting changes help explain why previously trained individuals can rebuild muscle faster later in life.
Image source: Public domain, PublicDomainPictures.net (muscle-man-2) https://www.publicdomainpictures.net/en/view-image.php?image=163621&picture=muscle-man-2
Positive and negative muscle memories
Muscle memory, however, has another side, as muscles also remember periods of inactivity, illness, or muscle loss. Younger muscle tends to form a positive memory, meaning it recovers well after time off; however, older muscle can develop a negative memory, making it more sensitive to wasting and slower to recover. Illness can have similar effects as studies of cancer survivors, for example, show that muscle cells can carry epigenetic markers associated with accelerated aging long after treatment ends. The encouraging news is that positive muscle memories can counteract negative ones, as research shows that regular exercise can help reset epigenetic patterns, restoring muscle function toward healthier levels, even much later in life. “Knowing my muscles actually remember workouts makes me want to stay on top of training,” Knox Pritchard ‘28 explained, revealing his encouragement of the recent discovery.
The takeaway for student athletes
Our muscles are smarter than we think, and the takeaway is definitely both sobering and hopeful. Our muscles remember both use and neglect with their own form of intelligence, and the more we use them, the more they store biological advantages. The advantages can support our health for many long years into the future. Every time we move, train, or exercise, we are building a biological memory that can benefit our body, as consistent activity not only makes us stronger and healthier today, but also creates lasting advantages stored directly inside our muscle cells.
Sources:
https://www.technologyreview.com/2025/10/10/1124963/muscles-remember-explained/
https://my.clevelandclinic.org/health/articles/muscle-memory
