Muscle memory is not what you think is

We all want Let’s know if and how we can go back to form after injury, illness or long hiatus. The muscles adapt to the environment: they grow when we put into work and contract when we stop. But what if we can help them remember how to grow?

As a general rule, cell biologists do not enter their careers by passing through the glove to the highest level professional sports. But in the years when Adam Sharples played as a front row in the Rugby Football League in the UK, he wondered about the cellular mechanisms that helped the muscles grow after various types of exercises.

The position of the front row in Pro Rugby means you have to be, well, “quite big”, as Adam says. “I was in the gym, lifting weights from around the age of 12, in my opinion,” he says.

He spent most of his life on a teenager in training. When he was 19, he played a match for the day of boxing on a wet ground that was heavy under his feet. He just planted his leg when a player in the opponent’s team coped with him by turning his upper body to the left. His right leg remained firmly in the mud.

“Then I tore my ACL, but I don’t remember much about it. I have to ask my father,” Adam tells me with a crooked smile. “He could tell you in a minute, with many details: when it happened, how it happened.” (Sport, reminds me, has the remarkable capacity to be a love language.)

Adam took a year from Rugby and continued to study, graduating from his master’s degree in human physiology. He has always been curious about muscles and muscle growth, but his hiatus gave him time to think – Pro Rugby players, he was well aware, have some short careers. This recognition eventually made him continue his doctoral degree in muscle cell biology.

When we talk about muscle memory, most of the time we treat the way our bodies seem to remember how to do things that we have not done in a while – to move with a bike, say, or do a complex dance that we learned in childhood. When you learn and repeat certain movements over time, this model of movement becomes advanced and regular, as well as the model of firing neurons that control this movement. The memory of how to perform this action lives in our motor neurons, not in the actual muscles that participate. But as Adam has gone through his academic training, he is increasingly interested in the question of whether the muscle itself has memory at the cellular and genetic level.

Almost two decades later, Adam teaches and manages a laboratory at the Norwegian School of Sports Sciences in Oslo. In 2018, his research group is the first in the world to show that the skeletal muscle of man has the epigenetic memory of muscle growth after exercise.

Epigenetic refers to changes in gene expression caused by behavior and environment. The genes themselves do not change, but as it works. When you lift weights, for example, small molecules called methyl groups are separated from the outside of certain genes, which makes them more likely to engage and produce proteins that affect muscle growth. These changes continue; If you start lifting weights again, you will add muscle mass faster than before. In other words, your muscles remember how to do it: they have a lasting molecular memory of past exercises that causes them to prepare to react to exercise, even after a monthly pause. (S)Cellular Muscle memory, on the other hand, works a little differently than epigenetic muscle memory. Exercise stimulates muscle stem cells to contribute to their nuclei for growth and muscle growth, and cell muscle memory applies when these nuclei stick to muscle fibers for some time – even after periods of inactivity – and help accelerate the return to growth after you start training again.)