Unlock the secrets of muscle memory and discover how your muscles can remember to grow and adapt, revolutionizing your approach to exercise and training.
Muscle Memory Isn’t What You Think It Is
In her new book On Muscle, Bonnie Tsui investigates the other stuff our muscles remember—like how to grow when you exercise.
The Science Behind Epigenetic Memory
When we talk about muscle memory, most of the time we refer to the way our bodies seem to remember how to do things that we haven’t done in some time—riding a bike, say, or doing a complicated dance we learned in childhood. However, this concept is often misunderstood. The memory of how to perform an action lives in our motor neurons, not in the actual muscles that are involved.
But what if we could help muscles remember how to grow? Recent research has shown that human skeletal muscle possesses an epigenetic memory of muscle growth after exercise. Epigenetic refers to changes in gene expression that are caused by behavior and environment. When you lift weights, small molecules called methyl groups detach from the outside of certain genes, making them more likely to turn on and produce proteins that affect muscle growth.
These changes persist, even after a months-long pause. In other words, your muscles remember how to do it: They have a lasting molecular memory of past exercise that makes them primed to respond to exercise, even after a period of inactivity. This concept is not just anecdotal; it’s backed by scientific evidence.
Muscle growth, also known as muscle hypertrophy, occurs when muscle fibers increase in size due to an overload of weightlifting or resistance exercises.
This process is triggered by micro-tears in the muscle tissue, which are repaired and rebuilt during rest periods.
Adequate protein intake, sufficient sleep, and a balanced diet support muscle growth.
Research shows that progressive overload, where weights are gradually increased over time, is essential for muscle growth.
Studies have found that muscle fibers can increase in size by up to 20% through regular exercise and proper nutrition.

Cellular Muscle Memory and the Role of Muscle Stem Cells
Cellular muscle memory works differently than epigenetic muscle memory. Exercise stimulates muscle stem cells to contribute their nuclei to muscle growth and repair, and cellular muscle memory refers to when those nuclei stick around for a while in the muscle fibers—even after periods of inactivity—and help accelerate the return to growth once you start training again.
Aging as an Athlete
Athletes have always known that it’s easier to regain lost muscle strength after a period of injury. However, understanding why this is the case can be complex. Adam Sharples, a former professional rugby player, took his reconstructed knee and ground through another year of pro rugby before retiring for good.
In his academic work, Adam Sharples investigated the reasons behind his observations about muscle memory. He found that if you can find the exercise that provides your muscle with the longest-lasting memory, or find the type of training that your muscle can respond better to the second time around—after an injury, say, or after taking some time off—you can potentially reduce the amount of exercise you do for the same benefit.
Regular exercise has numerous physical and mental health benefits.
It reduces the risk of chronic diseases, such as heart disease, diabetes, and certain cancers.
Exercise also improves sleep quality, boosts mood, and increases energy levels.
Additionally, it enhances cognitive function, including memory and concentration.
The 'World Health Organization recommends at least 150 minutes of moderate-intensity exercise or 75 minutes of vigorous-intensity exercise per week for adults.'
By understanding how muscles remember and adapt, athletes and individuals can optimize their training regimens to achieve better results. This knowledge has far-reaching implications beyond the world of sports, offering insights into aging and muscle growth that can be applied to various aspects of life.
Aging is a complex biological process that involves the gradual deterioration of cellular and organ function over time.
It is influenced by genetic, environmental, and lifestyle factors.
As we age, our cells undergo changes such as telomere shortening, epigenetic modifications, and increased oxidative stress.
This leads to decreased cellular division rates, DNA damage accumulation, and altered gene expression.
According to the World Health Organization (WHO), approximately 1 in 6 people worldwide suffer from age-related health issues.
- wired.com | Muscle Memory Isn’t What You Think It Is