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Resistance training induces muscle remodeling through epigenetic changes.
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More trained muscles become more efficient and resilient at the gene level during prolonged training.
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Understanding the mechanisms that regulate this transformation can improve training and have innovative medical applications.
The title of this article may understandably make you think, “Well, what a breakthrough: of course training changes muscles,” and you would have a point. What we mean, however-or rather the scientists at the University of Basel mean-is what changes in the muscles of those who exercise, not how they change.
In fact, the effect of training on muscle fibers has been known for millennia: the more they are stressed, the stronger they become. The more we keep ourselves moving, the greater our ability to withstand effort. Instead, how this is possible and what happens at the genetic level is the thesis this research seeks to prove.
Let’s start with the mice
The research involved laboratory mice and found that resistance training causes muscle remodeling, evident in differential expression of genes according to training status. These are the so-called “epigenetic changes,” which are those changes that occur at the genetic level without involving the structure of the DNA, which therefore remains unchanged. The result, in this case, is that trained muscles are more efficient and resilient during prolonged workouts.
In short, it seems that resistance training improves not only our overall fitness and well-being, but also changes our muscle structure. How and with what effects this occurs is something you can realize for yourself: the more you exercise, the less fatigued your muscles become, the more they are able to generate energy while being able to optimize oxygen use.
In the study, the research team compared muscles from untrained mice with trained ones and studied how gene expression changes in response to exercise. “Gene expression” means the process by which information contained in DNA is converted into a protein. To better understand what this is all about, let’s take an example related to running by talking about the oxygenation of muscles during sports activity. When your body is under stress, the gene for hemoglobin requires activation of the protein that carries oxygen in the blood so as to facilitate cellular respiration. In short, if your body needs more oxygen, the genes for hemoglobin “get expressed” more actively and this leads to the production of more hemoglobin, which can transport more oxygen to tissues. That is why it is important to understand the mechanisms that activate these processes and how training can stimulate them.
This is what the Basel scientists found, namely that about 250 genes changed expression in the muscles of trained versus untrained mice, while about 1,800 to 2,500 genes were activated after acute exercise. How many and which genes respond depends mainly on the state of training.
What it means in practice
As we said, that muscles change is no mystery: we see it ourselves! But how they change is different. For example, trained muscles respond completely differently to physical stress, and this can be best understood by comparing them with untrained muscles. The latter react to the stress of physical movement by activating inflammatory genes, causing the well-known muscle pains. In contrast, trained mice subjected to the same physical stress show greater activity among muscle-protecting genes. This is why trained muscles respond differently to the stress of exercise, being able to be more efficient and resilient.
In other words, what the scientists found is that resistance training alters–positively–the epigenetic pattern in muscle, both in the short and long term. In short, prolonged workouts modify trained muscles at the level of their epigenetic, as well as physical and molecular, patterns.
What’s in it for you now that you know? Well, it is not necessarily the case that research always has to adapt to contingent problems: in fact, it can also be the demonstration of particularly abstract theses that are not of immediate use. What can instead be found to be very useful is, for example, the possibility of improving one’s training no longer just on the basis of charts but on the intimate knowledge of how our muscles work, from a genetic point of view, that is, related to how our genes behave.
For example, these results can be applied in competitive sports by studying biomarkers that reflect training progress, improving training efficiency. In addition, understanding how a healthy muscle works is critical to understanding by comparison what happens to a muscle that is deteriorated by age or disease, thus enabling innovative therapies.
(via SciTech Daily)