I started off researching the idea of muscle memory with the idea that I would focus on how your muscles remember how to do certain actions even when you haven’t done those actions for long periods of time. For me, it has been playing my clarinet and dragon boating. It turns out that this will have to be the subject of another post. I got distracted by another type of muscle memory – myonuclei.
Without going into all the details, muscles are made up of fibres, which are basically really large cells with lots of nuclei (the epicenter of the cell, it contains all the DNA). These nuclei are myonuclei and where most cells only have one nucleus, muscle cells have several because each one has a limited area it can influence. You could think of the nucleus as a teacher in the classroom (cell). The teacher contains all the info the cell needs to function. But a muscle cell is way bigger than a normal classroom so it needs multiple teachers.
When we work out the cells get bigger (hypertrophy). Bigger cells need even more myonuclei. The body spends energy making the myonuclei. So here’s the cool part. The myonuclei remain during periods of atrophy, or muscle loss due to lack of use.
Why is this cool? Because it affects how long it takes the muscles to retrain and undergo hypertrophy again.
In other words, when you were in shape but something happened like an injury that caused a decrease in your normal fitness training, your muscle cells remain prepared for growth caused by re-training by keeping the extra myonuclei.
Going back to the teacher analogy, a school would keep the same number of teachers even if they lost students. This way it would still be prepared for extra students.
This obviously has the potential to affect recovery from injuries. It may also, as the study authors point out, mean that athletes caught using certain performance enhancing drugs may actually need to be banned for longer time periods, until all the benefits have disappeared. But I also wonder if it could open the door to make it more acceptable to take time away from your main competitive sport to try other things. All things to contemplate.